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Permezel F, Alty J, Harding IH, Thyagarajan D. Brain Networks Involved in Sensory Perception in Parkinson's Disease: A Scoping Review. Brain Sci 2023; 13:1552. [PMID: 38002513 PMCID: PMC10669548 DOI: 10.3390/brainsci13111552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Revised: 10/26/2023] [Accepted: 10/31/2023] [Indexed: 11/26/2023] Open
Abstract
Parkinson's Disease (PD) has historically been considered a disorder of motor dysfunction. However, a growing number of studies have demonstrated sensory abnormalities in PD across the modalities of proprioceptive, tactile, visual, auditory and temporal perception. A better understanding of these may inform future drug and neuromodulation therapy. We analysed these studies using a scoping review. In total, 101 studies comprising 2853 human participants (88 studies) and 125 animals (13 studies), published between 1982 and 2022, were included. These highlighted the importance of the basal ganglia in sensory perception across all modalities, with an additional role for the integration of multiple simultaneous sensation types. Numerous studies concluded that sensory abnormalities in PD result from increased noise in the basal ganglia and increased neuronal receptive field size. There is evidence that sensory changes in PD and impaired sensorimotor integration may contribute to motor abnormalities.
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Affiliation(s)
- Fiona Permezel
- Department of Neuroscience, Monash University, Melbourne 3004, Australia; (F.P.); (I.H.H.)
- Department of Neurology, Mayo Clinic, Rochester, MN 55901, USA
| | - Jane Alty
- Wicking Dementia Research and Education Centre, University of Tasmania, Hobart 7001, Australia;
| | - Ian H. Harding
- Department of Neuroscience, Monash University, Melbourne 3004, Australia; (F.P.); (I.H.H.)
| | - Dominic Thyagarajan
- Department of Neuroscience, Monash University, Melbourne 3004, Australia; (F.P.); (I.H.H.)
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2
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Subramaniam MD, Aishwarya Janaki P, Abishek Kumar B, Gopalarethinam J, Nair AP, Mahalaxmi I, Vellingiri B. Retinal Changes in Parkinson's Disease: A Non-invasive Biomarker for Early Diagnosis. Cell Mol Neurobiol 2023; 43:3983-3996. [PMID: 37831228 DOI: 10.1007/s10571-023-01419-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Accepted: 09/24/2023] [Indexed: 10/14/2023]
Abstract
Parkinson's disease (PD) is caused due to degeneration of dopaminergic neurons in the substantia nigra pars compacta (SNpc) which leads to the depletion of dopamine in the body. The lack of dopamine is mainly due to aggregation of misfolded α-synuclein which causes motor impairment in PD. Dopamine is also required for normal retinal function and the light-dark vision cycle. Misfolded α-synuclein present in inner retinal layers causes vision-associated problems in PD patients. Hence, individuals with PD also experience structural and functional changes in the retina. Mutation in LRRK2, PARK2, PARK7, PINK1, or SNCA genes and mitochondria dysfunction also play a role in the pathophysiology of PD. In this review, we discussed the different etiologies which lead to PD and future prospects of employing non-invasive techniques and retinal changes to diagnose the onset of PD earlier.
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Affiliation(s)
- Mohana Devi Subramaniam
- SN ONGC Department of Genetics and Molecular Biology, Vision Research Foundation, Sankara Nethralaya, Chennai, Tamil Nadu, 600 006, India.
| | - P Aishwarya Janaki
- SN ONGC Department of Genetics and Molecular Biology, Vision Research Foundation, Sankara Nethralaya, Chennai, Tamil Nadu, 600 006, India
| | - B Abishek Kumar
- SN ONGC Department of Genetics and Molecular Biology, Vision Research Foundation, Sankara Nethralaya, Chennai, Tamil Nadu, 600 006, India
| | - Janani Gopalarethinam
- SN ONGC Department of Genetics and Molecular Biology, Vision Research Foundation, Sankara Nethralaya, Chennai, Tamil Nadu, 600 006, India
| | - Aswathy P Nair
- SN ONGC Department of Genetics and Molecular Biology, Vision Research Foundation, Sankara Nethralaya, Chennai, Tamil Nadu, 600 006, India
| | - I Mahalaxmi
- Department of Biotechnology, Karpagam Academy of Higher Education (Deemed to be University), Coimbatore, 641021, India
| | - Balachandar Vellingiri
- Department of Zoology, School of Basic Sciences, Central University of Punjab, Bathinda, India
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3
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Elanwar R, Al Masry H, Ibrahim A, Hussein M, Ibrahim S, Masoud MM. Retinal functional and structural changes in patients with Parkinson's disease. BMC Neurol 2023; 23:330. [PMID: 37723424 PMCID: PMC10506234 DOI: 10.1186/s12883-023-03373-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2023] [Accepted: 09/07/2023] [Indexed: 09/20/2023] Open
Abstract
BACKGROUND Visual dysfunction have been well reported as one of the non-motor symptoms in Parkinson's disease (PD). The aim of this study was to evaluate the functional and structural changes in the retina in patients with PD, and to correlate these changes with disease duration and motor dysfunction. METHODS For this case-control study, we recruited patients fulfilling the diagnostic criteria for idiopathic PD according to British Brain Bank criteria, aged between 50 and 80 years. Age- and sex-matched healthy controls aged between 50 and 80 years were also recruited. Motor function for PD patients was assessed using Modified Hoehn and Yahr staging scale (H & Y staging) and Unified Parkinson's Disease Rating Scale (UPDRS). Optical Coherence Tomography (OCT) and full field electroretinogram (ff-ERG) were done to all participants. RESULTS Data from 50 patients and 50 healthy controls were included in the analysis. Patients with idiopathic Parkinson's had significantly reduced peripapillary retinal nerve fiber layer (RNFL) thickness and macular ganglion cell complex (GCC) thickness compared to healthy controls (P-value < 0.05 in all parameters). They also had significantly delayed latency and reduced amplitude in both dark-adapted rods and the light-adapted cone for both a & b waves compared to healthy controls (P-value < 0.001 in all parameters). There were statistically significant negative correlations between disease duration, and left superior, right inferior and right & left average RNFL thickness [(r) coef. = -0.327, -0.301, -0.275, and -0.285 respectively]. UPDRS total score was negatively correlated with the amplitude of light-adapted of both RT and LT a & b wave and with dark-adapted RT b-wave latency [(r) coef. = -0.311, -0.395, -0.362, -0.419, and -0.342]. CONCLUSION The retinal structure and function were significantly affected in patients with PD in comparison to healthy controls. There was a significant impact of disease duration on retinal thickness, and there was a significant negative correlation between the degree of motor dysfunction in patients with PD and retinal function.
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Affiliation(s)
- Rehab Elanwar
- Neuro Diagnostic Research Center, Beni-Suef University, Beni-Suef, Egypt
| | - Hatem Al Masry
- Department of Neurology, Beni-Suef University, Salah Salem Street, Beni-Suef, Egypt
| | - Amna Ibrahim
- Department of Neurology, Beni-Suef University, Salah Salem Street, Beni-Suef, Egypt
| | - Mona Hussein
- Department of Neurology, Beni-Suef University, Salah Salem Street, Beni-Suef, Egypt.
| | - Sahar Ibrahim
- Department of Ophthalmology, Beni-Suef University, Beni-Suef, 62511, Egypt
| | - Mohammed M Masoud
- Department of Neurology, Beni-Suef University, Salah Salem Street, Beni-Suef, Egypt
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Constable PA, Lim JKH, Thompson DA. Retinal electrophysiology in central nervous system disorders. A review of human and mouse studies. Front Neurosci 2023; 17:1215097. [PMID: 37600004 PMCID: PMC10433210 DOI: 10.3389/fnins.2023.1215097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Accepted: 07/17/2023] [Indexed: 08/22/2023] Open
Abstract
The retina and brain share similar neurochemistry and neurodevelopmental origins, with the retina, often viewed as a "window to the brain." With retinal measures of structure and function becoming easier to obtain in clinical populations there is a growing interest in using retinal findings as potential biomarkers for disorders affecting the central nervous system. Functional retinal biomarkers, such as the electroretinogram, show promise in neurological disorders, despite having limitations imposed by the existence of overlapping genetic markers, clinical traits or the effects of medications that may reduce their specificity in some conditions. This narrative review summarizes the principal functional retinal findings in central nervous system disorders and related mouse models and provides a background to the main excitatory and inhibitory retinal neurotransmitters that have been implicated to explain the visual electrophysiological findings. These changes in retinal neurochemistry may contribute to our understanding of these conditions based on the findings of retinal electrophysiological tests such as the flash, pattern, multifocal electroretinograms, and electro-oculogram. It is likely that future applications of signal analysis and machine learning algorithms will offer new insights into the pathophysiology, classification, and progression of these clinical disorders including autism, attention deficit/hyperactivity disorder, bipolar disorder, schizophrenia, depression, Parkinson's, and Alzheimer's disease. New clinical applications of visual electrophysiology to this field may lead to earlier, more accurate diagnoses and better targeted therapeutic interventions benefiting individual patients and clinicians managing these individuals and their families.
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Affiliation(s)
- Paul A. Constable
- College of Nursing and Health Sciences, Caring Futures Institute, Flinders University, Adelaide, SA, Australia
| | - Jeremiah K. H. Lim
- Discipline of Optometry, School of Allied Health, University of Western Australia, Perth, WA, Australia
| | - Dorothy A. Thompson
- The Tony Kriss Visual Electrophysiology Unit, Clinical and Academic Department of Ophthalmology, Great Ormond Street Hospital for Children NHS Trust, London, United Kingdom
- UCL Great Ormond Street Institute of Child Health, University College London, London, United Kingdom
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Tursini K, Remy I, Le Cam S, Louis-Dorr V, Malka-Mahieu H, Schwan R, Gross G, Laprévote V, Schwitzer T. Subsequent and simultaneous electrophysiological investigation of the retina and the visual cortex in neurodegenerative and psychiatric diseases: what are the forecasts for the medicine of tomorrow? Front Psychiatry 2023; 14:1167654. [PMID: 37333926 PMCID: PMC10272854 DOI: 10.3389/fpsyt.2023.1167654] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Accepted: 05/18/2023] [Indexed: 06/20/2023] Open
Abstract
Visual electrophysiological deficits have been reported in neurodegenerative disorders as well as in mental disorders. Such alterations have been mentioned in both the retina and the cortex, notably affecting the photoreceptors, retinal ganglion cells (RGCs) and the primary visual cortex. Interestingly, such impairments emphasize the functional role of the visual system. For this purpose, the present study reviews the existing literature with the aim of identifying key alterations in electroretinograms (ERGs) and visual evoked potentials electroencephalograms (VEP-EEGs) of subjects with neurodegenerative and psychiatric disorders. We focused on psychiatric and neurodegenerative diseases due to similarities in their neuropathophysiological mechanisms. Our research focuses on decoupled and coupled ERG/VEP-EEG results obtained with black-and-white checkerboards or low-level visual stimuli. A decoupled approach means recording first the ERG, then the VEP-EEG in the same subject with the same visual stimuli. The second method means recording both ERG and VEP-EEG simultaneously in the same participant with the same visual stimuli. Both coupled and decoupled results were found, indicating deficits mainly in the N95 ERG wave and the P100 VEP-EEG wave in Parkinson’s, Alzheimer’s, and major depressive disorder. Such results reinforce the link between the retina and the visual cortex for the diagnosis of psychiatric and neurodegenerative diseases. With that in mind, medical devices using coupled ERG/VEP-EEG measurements are being developed in order to further investigate the relationship between the retina and the visual cortex. These new techniques outline future challenges in mental health and the use of machine learning for the diagnosis of mental disorders, which would be a crucial step toward precision psychiatry.
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Affiliation(s)
- Katelyne Tursini
- Pôle Hospitalo-Universitaire de Psychiatrie d’Adultes et d’Addictologie du Grand Nancy, Centre Psychothérapique de Nancy, Laxou, France
- BioSerenity, Paris, France
- INSERM U1254, Université de Lorraine, IADI, Nancy, France
| | - Irving Remy
- Pôle Hospitalo-Universitaire de Psychiatrie d’Adultes et d’Addictologie du Grand Nancy, Centre Psychothérapique de Nancy, Laxou, France
- BioSerenity, Paris, France
- INSERM U1114, Université de Strasbourg, Strasbourg, France
| | - Steven Le Cam
- CRAN, CNRS UMR 7039, Université de Lorraine, Nancy, France
| | | | | | - Raymund Schwan
- Pôle Hospitalo-Universitaire de Psychiatrie d’Adultes et d’Addictologie du Grand Nancy, Centre Psychothérapique de Nancy, Laxou, France
- INSERM U1254, Université de Lorraine, IADI, Nancy, France
- Faculté de Médecine, Université de Lorraine, Vandœuvre-lès-Nancy, France
| | - Grégory Gross
- Pôle Hospitalo-Universitaire de Psychiatrie d’Adultes et d’Addictologie du Grand Nancy, Centre Psychothérapique de Nancy, Laxou, France
- INSERM U1254, Université de Lorraine, IADI, Nancy, France
| | - Vincent Laprévote
- Pôle Hospitalo-Universitaire de Psychiatrie d’Adultes et d’Addictologie du Grand Nancy, Centre Psychothérapique de Nancy, Laxou, France
- INSERM U1114, Université de Strasbourg, Strasbourg, France
- Faculté de Médecine, Université de Lorraine, Vandœuvre-lès-Nancy, France
| | - Thomas Schwitzer
- Pôle Hospitalo-Universitaire de Psychiatrie d’Adultes et d’Addictologie du Grand Nancy, Centre Psychothérapique de Nancy, Laxou, France
- INSERM U1254, Université de Lorraine, IADI, Nancy, France
- Faculté de Médecine, Université de Lorraine, Vandœuvre-lès-Nancy, France
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6
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Tran KKN, Wong VHY, Hoang A, Finkelstein DI, Bui BV, Nguyen CTO. Retinal alpha-synuclein accumulation correlates with retinal dysfunction and structural thinning in the A53T mouse model of Parkinson's disease. Front Neurosci 2023; 17:1146979. [PMID: 37214398 PMCID: PMC10196133 DOI: 10.3389/fnins.2023.1146979] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2023] [Accepted: 04/17/2023] [Indexed: 05/24/2023] Open
Abstract
Abnormal alpha-synuclein (α-SYN) protein deposition has long been recognized as one of the pathological hallmarks of Parkinson's disease's (PD). This study considers the potential utility of PD retinal biomarkers by investigating retinal changes in a well characterized PD model of α-SYN overexpression and how these correspond to the presence of retinal α-SYN. Transgenic A53T homozygous (HOM) mice overexpressing human α-SYN and wildtype (WT) control littermates were assessed at 4, 6, and 14 months of age (male and female, n = 15-29 per group). In vivo retinal function (electroretinography, ERG) and structure (optical coherence tomography, OCT) were recorded, and retinal immunohistochemistry and western blot assays were performed to examine retinal α-SYN and tyrosine hydroxylase. Compared to WT controls, A53T mice exhibited reduced light-adapted (cone photoreceptor and bipolar cell amplitude, p < 0.0001) ERG responses and outer retinal thinning (outer plexiform layer, outer nuclear layer, p < 0.0001) which correlated with elevated levels of α-SYN. These retinal signatures provide a high throughput means to study α-SYN induced neurodegeneration and may be useful in vivo endpoints for PD drug discovery.
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Affiliation(s)
- Katie K. N. Tran
- Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, VIC, Australia
| | - Vickie H. Y. Wong
- Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, VIC, Australia
| | - Anh Hoang
- Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, VIC, Australia
| | - David I. Finkelstein
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia
| | - Bang V. Bui
- Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, VIC, Australia
| | - Christine T. O. Nguyen
- Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, VIC, Australia
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Alves JN, Westner BU, Højlund A, Weil RS, Dalal SS. Structural and functional changes in the retina in Parkinson's disease. J Neurol Neurosurg Psychiatry 2023; 94:448-456. [PMID: 36806480 PMCID: PMC7614544 DOI: 10.1136/jnnp-2022-329342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 01/05/2023] [Indexed: 02/19/2023]
Abstract
Parkinson's disease is caused by degeneration of dopaminergic neurons, originating in the substantia nigra pars compacta and characterised by bradykinesia, rest tremor and rigidity. In addition, visual disorders and retinal abnormalities are often present and can be identified by decreased visual acuity, abnormal spatial contrast sensitivity or even difficulty in complex visual task completion. Because of their early onset in patients with de novo Parkinson's disease, the anatomical retinal changes and electrophysiological modification could be valuable markers even at early stages of the disease. However, due to the concomitant occurrence of normal ageing, the relevance and specificity of these predictive values can be difficult to interpret. This review examines retinal dysfunction arising in Parkinson's disease. We highlight the electrophysiological delays and decreased amplitude in the electroretinography recorded in patients and animal models. We relate this to coexisting anatomical changes such as retinal nerve fibre layer and macular thinning, measured using optical coherence tomography, and show that functional measures are more consistent overall than optical coherence-measured structural changes. We review the underlying chemical changes seen with loss of retinal dopaminergic neurons and the effect of levodopa treatment on the retina in Parkinson's disease. Finally, we consider whether retinal abnormalities in Parkinson's disease could have a role as potential markers of poorer outcomes and help stratify patients at early stages of the disease. We emphasise that retinal measures can be valuable, accessible and cost-effective methods in the early evaluation of Parkinson's disease pathogenesis with potential for patient stratification.
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Affiliation(s)
- Jordan N Alves
- Center of Functionally Integrative Neuroscience, Aarhus University, Aarhus, Denmark
| | - Britta U Westner
- Radboud University, Donders Institute for Brain, Cognition and Behaviours, Nijmegen, The Netherlands
| | - Andreas Højlund
- Department of Linguistics, Cognitive Science & Semiotics, Aarhus University, Aarhus, Denmark
| | - Rimona Sharon Weil
- Dementia Research Centre, University College London, London, UK.,Movement Disorders Consortium, University College London, London, UK.,Wellcome Centre for Human Neuroimaging, University College London, London, UK
| | - Sarang S Dalal
- Center of Functionally Integrative Neuroscience, Aarhus University, Aarhus, Denmark
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The Relationship between Visual-Evoked Potential and Optic Coherence Tomography and Clinical Findings in Parkinson Patients. PARKINSON'S DISEASE 2023; 2023:7739944. [PMID: 36873294 PMCID: PMC9981293 DOI: 10.1155/2023/7739944] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Revised: 12/14/2022] [Accepted: 01/18/2023] [Indexed: 02/25/2023]
Abstract
Background In Parkinson's disease (PD), dopamine deficiency is present not only in the nigrostriatal pathway but also in the retinal and visual pathways. Optic coherence tomography (OCT) can be used as morphological evidence of visual influence from early nonmotor symptoms. The aim of this study was to investigate the relationship of OCT and visual evoked potentials (VEPs) of eyes with the severity of clinical findings and ocular findings in PD. Methods A group of 42 patients diagnosed with idiopathic PD and a control group of 29 people between the ages of 45-85 were included in our study. VEP was recorded in the patient and control groups. OCT measurement was made with the Optovue spectral-domain device. Foveal thickness and macular volume were measured in the foveal region and in the parafoveal and perifoveal regions in the temporal, superior, nasal, and inferior quadrants. RNFL (retinal nerve fiber layer) was measured in temporal, superior, nasal, and inferior quadrants. Ganglion cell complex (GCC) was evaluated in the superior and inferior quadrants. Using the UPDRS clinical scale, the relationship between measurements and the differences between the control group and the patient group were evaluated. Results Among the OCT values in our study, foveal, parafoveal, perifoveal thickness, macular volume, RNFL, and GCC measurements were performed for the right and left eyes, and no difference was found between the patient group and the control group. There was no difference in VEP amplitude and latency values between the patient and control groups. The relationships between UPDRS and modified Hoehn Yahr staging and OCT and VEP measurements in the patient revealed no correlation. Conclusions Studies on whether OCT measurements can functionally be a marker or which segments are more valuable for disease progression in patients with PD are needed. Visual dysfunction in PD cannot be attributed only to retinal pathology; however, the retina may provide monitoring of the status of dopaminergic neurodegeneration and axonal loss in PD.
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Macular function in patients with medium myopia. Doc Ophthalmol 2022; 146:113-120. [PMID: 36463559 PMCID: PMC10082121 DOI: 10.1007/s10633-022-09907-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Accepted: 10/12/2022] [Indexed: 12/07/2022]
Abstract
Abstract
Purpose
This work aims at assessing whether electrophysiological functional changes in the macular region appear in medium myopia, even in the presence of a normal macular OCT scan and how axial length correlates with macular OCT parameters in medium myopia.
Methods
The study included right eyes of 17 patients with myopia of medium degree (SE < − 6D to > − 3D). Control group consisted of 20 eyes of patients of age and sex that matched healthy controls with normal macular and optic nerve OCT results and normal axial length. Full ophthalmic examination (the distance best-corrected visual acuity, intraocular pressure, refractive error, the anterior and posterior segment of the eye in a slit lamp, the axial length of the eyeball) with OCT of the macular and optic disk and the PERG test were performed in the study and control groups. Only the patients with normal ophthalmic and OCT examination results were qualified. The interview covering questions on risk factors of myopia onset and progression such as prematurity, family history of myopia was carried out in both groups. In myopic group, the question relating to time of near work was also asked. Study and control groups were tested with the use of Shapiro–Wilk, Mann–Whitney, Student’s t test, Pearson and Spearman's rank correlation tests.
Results
AL was significantly longer in myopia group (p < 0.01), and SE value was lower (p < 0.01). Longer implicit time of P50 was found in the study group, but amplitudes of P50 and N95 waves were not significantly reduced (p < 0.05). AL showed correlations with P50 implicit time (p < 0.05) and with reduction in retinal fiber nerve layer and ganglion cells and inner plexus layer (p < 0.05).
Conclusion
Patients with myopia of medium degree have a dysfunction of retinal cone system of the macular region even when OCT scans show no abnormalities. Elongation of AL correlates with reduction in retinal fiber nerve layer and ganglion cells and inner plexus layer. Longitudinal follow-up studies may answer the question whether this increase in implicit time may be indicative of a faster myopia progression or of myopic retinal pathology, i.e., whether it may help to determine which patient would benefit from earlier or more intensive management of myopia progression.
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Veys L, Devroye J, Lefevere E, Cools L, Vandenabeele M, De Groef L. Characterizing the Retinal Phenotype of the Thy1-h[A30P]α-syn Mouse Model of Parkinson's Disease. Front Neurosci 2021; 15:726476. [PMID: 34557068 PMCID: PMC8452874 DOI: 10.3389/fnins.2021.726476] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 08/19/2021] [Indexed: 12/30/2022] Open
Abstract
Despite decades of research, disease-modifying treatments of Parkinson’s disease (PD), the second most common neurodegenerative disease worldwide, remain out of reach. One of the reasons for this treatment gap is the incomplete understanding of how misfolded alpha-synuclein (α-syn) contributes to PD pathology. The retina, as an integral part of the central nervous system, recapitulates the PD disease processes that are typically seen in the brain, and retinal manifestations have emerged as prodromal symptoms of the disease. The timeline of PD manifestations in the visual system, however, is not fully elucidated and the underlying mechanisms are obscure. This highlights the need for new studies investigating retinal pathology, in order to propel its use as PD biomarker, and to develop validated research models to investigate PD pathogenesis. The present study pioneers in characterizing the retina of the Thy1-h[A30P]α-syn PD transgenic mouse model. We demonstrate widespread α-syn accumulation in the inner retina of these mice, of which a proportion is phosphorylated yet not aggregated. This α-syn expression coincides with inner retinal atrophy due to postsynaptic degeneration. We also reveal abnormal retinal electrophysiological responses. Absence of selective loss of melanopsin retinal ganglion cells or dopaminergic amacrine cells and inflammation indicates that the retinal manifestations in these transgenic mice diverge from their brain phenotype, and questions the specific cellular or molecular alterations that underlie retinal pathology in this PD mouse model. Nevertheless, the observed α-syn accumulation, synapse loss and functional deficits suggest that the Thy1-h[A30P]α-syn retina mimics some of the features of prodromal PD, and thus may provide a window to monitor and study the preclinical/prodromal stages of PD, PD-associated retinal disease processes, as well as aid in retinal biomarker discovery and validation.
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Affiliation(s)
- Lien Veys
- Research Group of Neural Circuit Development and Regeneration, Department of Biology, KU Leuven, Leuven, Belgium.,Department of Biomedical Sciences, Leuven Brain Institute, Leuven, Belgium
| | - Joyce Devroye
- Research Group of Neural Circuit Development and Regeneration, Department of Biology, KU Leuven, Leuven, Belgium.,Department of Biomedical Sciences, Leuven Brain Institute, Leuven, Belgium
| | - Evy Lefevere
- Research Group of Neural Circuit Development and Regeneration, Department of Biology, KU Leuven, Leuven, Belgium.,Department of Biomedical Sciences, Leuven Brain Institute, Leuven, Belgium
| | - Lien Cools
- Research Group of Neural Circuit Development and Regeneration, Department of Biology, KU Leuven, Leuven, Belgium.,Department of Biomedical Sciences, Leuven Brain Institute, Leuven, Belgium
| | - Marjan Vandenabeele
- Research Group of Neural Circuit Development and Regeneration, Department of Biology, KU Leuven, Leuven, Belgium.,Department of Biomedical Sciences, Leuven Brain Institute, Leuven, Belgium
| | - Lies De Groef
- Research Group of Neural Circuit Development and Regeneration, Department of Biology, KU Leuven, Leuven, Belgium.,Department of Biomedical Sciences, Leuven Brain Institute, Leuven, Belgium
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11
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Past, present and future role of retinal imaging in neurodegenerative disease. Prog Retin Eye Res 2021; 83:100938. [PMID: 33460813 PMCID: PMC8280255 DOI: 10.1016/j.preteyeres.2020.100938] [Citation(s) in RCA: 55] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 12/11/2020] [Accepted: 12/17/2020] [Indexed: 02/08/2023]
Abstract
Retinal imaging technology is rapidly advancing and can provide ever-increasing amounts of information about the structure, function and molecular composition of retinal tissue in humans in vivo. Most importantly, this information can be obtained rapidly, non-invasively and in many cases using Food and Drug Administration-approved devices that are commercially available. Technologies such as optical coherence tomography have dramatically changed our understanding of retinal disease and in many cases have significantly improved their clinical management. Since the retina is an extension of the brain and shares a common embryological origin with the central nervous system, there has also been intense interest in leveraging the expanding armamentarium of retinal imaging technology to understand, diagnose and monitor neurological diseases. This is particularly appealing because of the high spatial resolution, relatively low-cost and wide availability of retinal imaging modalities such as fundus photography or OCT compared to brain imaging modalities such as magnetic resonance imaging or positron emission tomography. The purpose of this article is to review and synthesize current research about retinal imaging in neurodegenerative disease by providing examples from the literature and elaborating on limitations, challenges and future directions. We begin by providing a general background of the most relevant retinal imaging modalities to ensure that the reader has a foundation on which to understand the clinical studies that are subsequently discussed. We then review the application and results of retinal imaging methodologies to several prevalent neurodegenerative diseases where extensive work has been done including sporadic late onset Alzheimer's Disease, Parkinson's Disease and Huntington's Disease. We also discuss Autosomal Dominant Alzheimer's Disease and cerebrovascular small vessel disease, where the application of retinal imaging holds promise but data is currently scarce. Although cerebrovascular disease is not generally considered a neurodegenerative process, it is both a confounder and contributor to neurodegenerative disease processes that requires more attention. Finally, we discuss ongoing efforts to overcome the limitations in the field and unmet clinical and scientific needs.
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12
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Apathy and Anhedonia: Clinical and Neurophysiological Assessment of a Romanian Cohort. Brain Sci 2021; 11:brainsci11060729. [PMID: 34072624 PMCID: PMC8229756 DOI: 10.3390/brainsci11060729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 05/23/2021] [Accepted: 05/28/2021] [Indexed: 11/30/2022] Open
Abstract
Background: Patients with Parkinson’s disease (PD) often have, besides the characteristic motor manifestations, a wide variety of non-motor symptoms. These include apathy and anhedonia, common issues in PD, which can be quantified with the help of evaluation scales recommended by the literature. There are sensory non-motor manifestations of PD, some of which are easy to detect through electrophysiological studies. Our aim was to investigate the possible association of apathy and anhedonia with the severity of the motor status in a sample of PD patients in Romania. We also examined the prevalence of latency changes in the P100 wave of visual evoked potentials (VEPs) and how they correlated with motor status, apathy, and anhedonia in PD patients. Methods: Thirty-four patients with PD participated in this study. All were assessed for motor status using the Unified Parkinson’s Disease Rating Scale (UPDRS) and were rated on the Hoehn and Yahr scales. The presence and severity of apathy and anhedonia were assessed using the Apathy Evaluation Scale (AES), the Dimensional Apathy Scale (DAS), the Lille Apathy Rating Scale (LARS), and the Snaith–Hamilton Pleasure Scale (SHAPS). The latency of the P100 wave of the VEP was measured in all the patients. Results: Apathy and anhedonia were common among the patients with PD (35% and 58.8%, respectively). The presence of apathy/anhedonia was correlated with the severity of motor symptoms, as assessed using the UPDRS scale (p < 0.001), and with the stage of the disease according to the Hoehn and Yahr scale (p < 0.001). A prolonged latency of the P100 wave of the VEP was observed among apathetic (p < 0.001)/anhedonic (p < 0.01) patients and those with increased disease severity (p < 0.001). Conclusion: Apathy and anhedonia are common in PD and may correlate with the severity of motor symptoms. There may be visual impairment in these patients, evidenced by a prolonged P100 latency, which correlates with the severity of disease. Significance: Scales for assessing apathy and anhedonia, as well as measuring VEP latency, could be useful in assessing the severity of disease.
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Carrarini C, Russo M, Pagliaccio G, Dono F, Franciotti R, Deluca G, Nanni S, Saracino A, Onofrj M, Bonanni L. Visual evoked potential abnormalities in dementia with Lewy bodies. Neurophysiol Clin 2021; 51:425-431. [PMID: 33653623 DOI: 10.1016/j.neucli.2021.02.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 02/15/2021] [Accepted: 02/15/2021] [Indexed: 11/30/2022] Open
Abstract
OBJECTIVES Visuo-perceptual deficits and visual hallucinations (VHs) are common disturbances in patients with dementia with Lewy bodies (DLB) and those with Parkinson's disease (PD). In particular, delays in visual evoked potential (VEP), reversed by l-dopa administration, have previously been observed in PD patients. Impairment in metabolic functions of dopaminergic amacrine cells within the inner plexiform layer of the retina has been largely documented and has been posited as the underlying cause of visual and retinal alterations in PD. The aims of the present study were to investigate the presence of VEP abnormalities in DLB patients, as compared to a PD control group, and to assess the presence of significant correlations between neurophysiological measures and clinical symptoms (i.e., presence of visuospatial deficits and/or visual hallucinations). METHODS Fifteen DLB patients and fifteen matched PD patients underwent pattern reversal before and after l-dopa administration, and a short neuropsychological assessment. RESULTS In DLB patients, we observed delay of the P100 latency to foveal stimuli in both eyes compared to normative values. Compared to PD, DLB patients showed higher values of the P100 latency for foveal stimulation from the right eye prior to l-dopa administration (p = 0.018). No correlations between VEP alterations, visuo-spatial deficit and visual hallucinations were found. DISCUSSION Our findings demonstrated a longer P100 delay in DLB than in PD patients, especially along the right visual pathway. In contrast to previous studies, which focused on a dopaminergic pre-geniculate impairment of visual pathways, our evidence suggests that other mechanisms, possibly relying on thalamic involvement, which is known to be dysfunctional in DLB, can interfere with VEP abnormalities.
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Affiliation(s)
- Claudia Carrarini
- Department of Neuroscience, Imaging and Clinical Sciences, University G. d'Annunzio of Chieti-Pescara, Italy
| | - Mirella Russo
- Department of Neuroscience, Imaging and Clinical Sciences, University G. d'Annunzio of Chieti-Pescara, Italy
| | | | - Fedele Dono
- Department of Neuroscience, Imaging and Clinical Sciences, University G. d'Annunzio of Chieti-Pescara, Italy
| | - Raffaella Franciotti
- Department of Neuroscience, Imaging and Clinical Sciences, University G. d'Annunzio of Chieti-Pescara, Italy
| | - Giulia Deluca
- Department of Neurology, SS Annunziata Hospital, Chieti, Italy
| | - Stefania Nanni
- Department of Neurology, SS Annunziata Hospital, Chieti, Italy
| | | | - Marco Onofrj
- Department of Neuroscience, Imaging and Clinical Sciences, University G. d'Annunzio of Chieti-Pescara, Italy; Department of Neurology, SS Annunziata Hospital, Chieti, Italy
| | - Laura Bonanni
- Department of Neuroscience, Imaging and Clinical Sciences, University G. d'Annunzio of Chieti-Pescara, Italy; Department of Neurology, SS Annunziata Hospital, Chieti, Italy.
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Netser R, Demmin DL, Dobkin R, Goldstein A, Roché M, Netser Zernik A, Silverstein SM. Flash Electroretinography Parameters and Parkinson's Disease. JOURNAL OF PARKINSONS DISEASE 2020; 11:251-259. [PMID: 33074189 DOI: 10.3233/jpd-191830] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND Parkinson's disease (PD) is known to affect retinal structure and activity. As such, retinal evaluations may be used to develop objective and possibly early PD diagnostic tools. OBJECTIVE The aim of this study was to investigate the effects of Parkinson's disease (PD) manifestation and treatment on retinal activity. METHODS Data were collected on 21 participants diagnosed with PD, including the number of medications taken, clinical scales and flash electroretinography (fERG) measurements, under light-adapted and dark-adapted conditions. The fERG parameters measured included a-wave and b-wave amplitude and implicit time (i.e., latency). First, we investigated correlations between symptom measure scores and the fERG parameters. Next, we divided participants into two groups based on their antiparkinsonian medication load and analyzed differences between these groups' fERG parameters. RESULTS fERG parameters were strongly correlated with a number of clinical variables, including motor and non-motor symptoms and age at PD onset. Photoreceptor cell implicit time was longer among participants taking one or less antiparkinsonian medication as compared to those taking two or more. However, overall there was not strong evidence of a relationship between the number of antiparkinsonian medications taken and the fERG parameters. CONCLUSION Findings suggest that fERG may be a useful, non-intrusive measure of retinal, and, perhaps overall CNS function, in PD. However, additional studies in larger samples are needed to clarify this association.
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Affiliation(s)
- Roni Netser
- Shalvata Mental Health Center, Hod Hasharon, Israel
| | - Docia L Demmin
- Department of Psychology, Rutgers University, Piscataway, NJ, USA
| | - Roseanne Dobkin
- Department of Psychiatry, Rutgers - Robert Wood Johnson Medical School, Piscataway, NJ, USA
| | - Ariel Goldstein
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ, USA
| | - Matthew Roché
- Rutgers University - University Behavioral Health Care, Piscataway, NJ, USA
| | | | - Steven M Silverstein
- Department of Psychiatry, Rutgers - Robert Wood Johnson Medical School, Piscataway, NJ, USA.,Rutgers University - University Behavioral Health Care, Piscataway, NJ, USA.,Department of Ophthalmology, Rutgers - Robert Wood Johnson Medical School, Piscataway, NJ, USA.,Departments of Psychiatry, Neuroscience, and Ophthalmology, University of Rochester Medical Center, Rochester, NY, USA
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15
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Pinkhardt EH, Ding Y, Slotnick S, Kassubek J, Ludolph AC, Glazman S, Selesnick I, Bodis-Wollner I. The intrinsically restructured fovea is correlated with contrast sensitivity loss in Parkinson's disease. J Neural Transm (Vienna) 2020; 127:1275-1283. [PMID: 32676747 DOI: 10.1007/s00702-020-02224-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 06/30/2020] [Indexed: 10/23/2022]
Abstract
Foveal structure that is specified by the thickness, depth and the overall shape of the fovea is a promising tool to qualify and quantify retinal pathology in Parkinson's disease. To determine the model variable that is best suited for discriminating Parkinson's disease eyes from those of healthy controls and to assess correlations between impaired contrast sensitivity and foveal shape we characterized the fovea in 48 Parkinson's disease patients and 45 control subjects by optical coherence tomography (OCT). The model quantifies structural changes in the fovea of Parkinson's disease patients that are correlated with a decline in contrast sensitivity. Retinal foveal remodeling may serve as a parameter for vision deficits in Parkinson's disease. Whether foveal remodeling reflects dopaminergic driven pathology or rather both dopaminergic and non-dopaminergic pathology has to be investigated in longitudinal studies.
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Affiliation(s)
- Elmar H Pinkhardt
- Department of Neurology, Ulm University, Oberer Eselsberg 45, 89081, Ulm, Germany
| | - Yin Ding
- Department of Electrical and Computer Engineering, Polytechnic Institute of New York University, Brooklyn, NY, 11203, USA
| | | | - Jan Kassubek
- Department of Neurology, Ulm University, Oberer Eselsberg 45, 89081, Ulm, Germany
| | - Albert C Ludolph
- Department of Neurology, Ulm University, Oberer Eselsberg 45, 89081, Ulm, Germany
| | - Sofya Glazman
- Downstate Medical Center, State University of New York, Brooklyn, NY, USA
| | - Ivan Selesnick
- Department of Electrical and Computer Engineering, Polytechnic Institute of New York University, Brooklyn, NY, 11203, USA
| | - Ivan Bodis-Wollner
- Downstate Medical Center, State University of New York, Brooklyn, NY, USA. .,SUNY Eye Institute, State University of New York, New York, NY, USA.
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Silverstein SM, Demmin DL, Schallek JB, Fradkin SI. Measures of Retinal Structure and Function as Biomarkers in Neurology and Psychiatry. Biomark Neuropsychiatry 2020. [DOI: 10.1016/j.bionps.2020.100018] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
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17
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d'Isa R, Castoldi V, Marenna S, Santangelo R, Comi G, Leocani L. A new electrophysiological non-invasive method to assess retinocortical conduction time in the Dark Agouti rat through the simultaneous recording of electroretinogram and visual evoked potential. Doc Ophthalmol 2020; 140:245-255. [PMID: 31832898 DOI: 10.1007/s10633-019-09741-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Accepted: 12/06/2019] [Indexed: 11/25/2022]
Abstract
PURPOSE To develop a non-invasive method exploiting simultaneous recording of epidermal visual evoked potential (VEP) and epicorneal electroretinogram (ERG) to study retinocortical function and to evaluate its reliability and repeatability over time. METHODS Female wild-type DA rats were anesthetized with ketamine/xylazine (40/5 mg/kg). Epidermal VEP (Ag/AgCl cup electrode on scalp) and epicorneal ERG (gold ring electrode on eye surface) were recorded simultaneously in response to flash stimulation. RESULTS ANOVA for repeated measures showed that peak times of ERG b-wave and of VEP N1 and P2 were stable across 6 weekly time-points, as well as the corresponding amplitudes. Mean retinocortical time from b-wave to N1 (RCT1) was 7.6 ms and remained comparable across the 6 time-points. Mean retinocortical time from b-wave to P2 (RCT2) was 28.7 ms and did not show significant variations over time. Coefficient of variation (CoV%) and CoV% adjusted for sample size, namely relative standard error (RSE%), were calculated as indexes of repeatability. Good RSE% over time was obtained (< 5% for b-wave, N1 and P2 peak times; < 20% and < 7% for RCT1 and RCT2, respectively). CONCLUSIONS Simultaneous recording of ERG and VEP has been previously achieved through invasive methods requiring surgery. Here, we present a new non-invasive method, which allowed to obtain peak and retinocortical times that were constant across a long period and had a good repeatability over time. This method will ensure not only a gain in animal welfare, but will also avoid stress and eye or brain lesions which can interfere with experimental variables.
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Affiliation(s)
- Raffaele d'Isa
- Institute of Experimental Neurology (INSPE), San Raffaele Scientific Institute, IRCCS-San Raffaele Hospital, Via Olgettina 60, 20132, Milan, Italy
| | - Valerio Castoldi
- Institute of Experimental Neurology (INSPE), San Raffaele Scientific Institute, IRCCS-San Raffaele Hospital, Via Olgettina 60, 20132, Milan, Italy
- Vita-Salute San Raffaele University, Via Olgettina 58, 20132, Milan, Italy
| | - Silvia Marenna
- Institute of Experimental Neurology (INSPE), San Raffaele Scientific Institute, IRCCS-San Raffaele Hospital, Via Olgettina 60, 20132, Milan, Italy
- Vita-Salute San Raffaele University, Via Olgettina 58, 20132, Milan, Italy
| | - Roberto Santangelo
- Institute of Experimental Neurology (INSPE), San Raffaele Scientific Institute, IRCCS-San Raffaele Hospital, Via Olgettina 60, 20132, Milan, Italy
- Vita-Salute San Raffaele University, Via Olgettina 58, 20132, Milan, Italy
| | - Giancarlo Comi
- Institute of Experimental Neurology (INSPE), San Raffaele Scientific Institute, IRCCS-San Raffaele Hospital, Via Olgettina 60, 20132, Milan, Italy
- Vita-Salute San Raffaele University, Via Olgettina 58, 20132, Milan, Italy
| | - Letizia Leocani
- Institute of Experimental Neurology (INSPE), San Raffaele Scientific Institute, IRCCS-San Raffaele Hospital, Via Olgettina 60, 20132, Milan, Italy.
- Vita-Salute San Raffaele University, Via Olgettina 58, 20132, Milan, Italy.
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18
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Altered dynamics of visual contextual interactions in Parkinson's disease. NPJ PARKINSONS DISEASE 2019; 5:13. [PMID: 31286057 PMCID: PMC6609710 DOI: 10.1038/s41531-019-0085-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Accepted: 05/29/2019] [Indexed: 01/09/2023]
Abstract
Over the last decades, psychophysical and electrophysiological studies in patients and animal models of Parkinson's disease (PD), have consistently revealed a number of visual abnormalities. In particular, specific alterations of contrast sensitivity curves, electroretinogram (ERG), and visual-evoked potentials (VEP), have been attributed to dopaminergic retinal depletion. However, fundamental mechanisms of cortical visual processing, such as normalization or "gain control" computations, have not yet been examined in PD patients. Here, we measured electrophysiological indices of gain control in both space (surround suppression) and time (sensory adaptation) in PD patients based on steady-state VEP (ssVEP). Compared with controls, patients exhibited a significantly higher initial ssVEP amplitude that quickly decayed over time, and greater relative suppression of ssVEP amplitude as a function of surrounding stimulus contrast. Meanwhile, EEG frequency spectra were broadly elevated in patients relative to controls. Thus, contrary to what might be expected given the reduced contrast sensitivity often reported in PD, visual neural responses are not weaker; rather, they are initially larger but undergo an exaggerated degree of spatial and temporal gain control and are embedded within a greater background noise level. These differences may reflect cortical mechanisms that compensate for dysfunctional center-surround interactions at the retinal level.
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19
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Veys L, Vandenabeele M, Ortuño-Lizarán I, Baekelandt V, Cuenca N, Moons L, De Groef L. Retinal α-synuclein deposits in Parkinson's disease patients and animal models. Acta Neuropathol 2019; 137:379-395. [PMID: 30721408 DOI: 10.1007/s00401-018-01956-z] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2018] [Revised: 12/22/2018] [Accepted: 12/22/2018] [Indexed: 12/21/2022]
Abstract
Despite decades of research, accurate diagnosis of Parkinson's disease remains a challenge, and disease-modifying treatments are still lacking. Research into the early (presymptomatic) stages of Parkinson's disease and the discovery of novel biomarkers is of utmost importance to reduce this burden and to come to a more accurate diagnosis at the very onset of the disease. Many have speculated that non-motor symptoms could provide a breakthrough in the quest for early biomarkers of Parkinson's disease, including the visual disturbances and retinal abnormalities that are seen in the majority of Parkinson's disease patients. An expanding number of clinical studies have investigated the use of in vivo assessments of retinal structure, electrophysiological function, and vision-driven tasks as novel means for identifying patients at risk that need further neurological examination and for longitudinal follow-up of disease progression in Parkinson's disease patients. Often, the results of these studies have been interpreted in relation to α-synuclein deposits and dopamine deficiency in the retina, mirroring the defining pathological features of Parkinson's disease in the brain. To better understand the visual defects seen in Parkinson's disease patients and to propel the use of retinal changes as biomarkers for Parkinson's disease, however, more conclusive neuropathological evidence for the presence of retinal α-synuclein aggregates, and its relation to the cerebral α-synuclein burden, is urgently needed. This review provides a comprehensive and critical overview of the research conducted to unveil α-synuclein aggregates in the retina of Parkinson's disease patients and animal models, and thereby aims to aid the ongoing discussion about the potential use of the retinal changes and/or visual symptoms as biomarkers for Parkinson's disease.
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20
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Fujisawa Y, Minato T, Uemura JI, Hoshiyama M, Watanabe H, Hirayama M. Association between changes in visual evoked magnetic fields and non-motor features in Parkinson's disease. NAGOYA JOURNAL OF MEDICAL SCIENCE 2018. [PMID: 28626250 PMCID: PMC5472540 DOI: 10.18999/nagjms.79.2.147] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Visual dysfunction can be caused by several abnormalities, including dysfunctions in the visual cortex and retina. Our aim was to investigate changes in visual evoked brain responses in the primary visual cortex associated with Parkinson’s disease (PD). Sixteen healthy control subjects and ten patients with PD participated in this study. We assessed the visual evoked magnetic field (VEF) using magnetoencephalography (MEG). Checkerboard pattern reversal (CPR) and monotonous grating pattern (MGP) stimulations were used. Magnetic resonance imaging (MRI) was performed to analyze brain volume and generate a tractogram. Cognitive and olfactory function, and Unified Parkinson’s Disease Rating Scale (UPDRS) scores were evaluated in patients with PD. Four components of the VEF (1M, 2M, 3M, 4M) were observed following stimulation. For both stimuli, results from the 1M and 2M components were significantly greater and the latency of the 1M component was increased markedly in the PD group compared with the healthy control group. In the PD group, 1M latency correlated with the UPDRS score of 1 for both stimuli, and a correlation was observed between olfactory function and the UPDRS score of 3 for the CPR stimulation alone. We suggest that the conduction delay observed following visual stimulation occurs peripherally rather than in the primary visual cortex. Degeneration of selective elements of the visual system in the retina, possibly midget cells, may be involved.
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Affiliation(s)
- Yoshiro Fujisawa
- Department of Pathophysiological Laboratory Sciences, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Tomomi Minato
- Department of Pathophysiological Laboratory Sciences, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Jun-Ichi Uemura
- Department of Pathophysiological Laboratory Sciences, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Minoru Hoshiyama
- Department of Pathophysiological Laboratory Sciences, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Hirohisa Watanabe
- Department of Pathophysiological Laboratory Sciences, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Masaaki Hirayama
- Department of Pathophysiological Laboratory Sciences, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
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Guo L, Normando EM, Shah PA, De Groef L, Cordeiro MF. Oculo-visual abnormalities in Parkinson's disease: Possible value as biomarkers. Mov Disord 2018; 33:1390-1406. [DOI: 10.1002/mds.27454] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Revised: 05/16/2018] [Accepted: 05/18/2018] [Indexed: 12/16/2022] Open
Affiliation(s)
- Li Guo
- Glaucoma and Retinal Degenerative Disease Research Group, Institute of Ophthalmology; University College London; London UK
| | - Eduardo M. Normando
- Glaucoma and Retinal Degenerative Disease Research Group, Institute of Ophthalmology; University College London; London UK
- Western Eye Hospital, Imperial College Healthcare National Health Service Trust; London UK
- Imperial College Ophthalmology Research Group, Department of Surgery and Cancer, Imperial College London; London UK
| | - Parth Arvind Shah
- Glaucoma and Retinal Degenerative Disease Research Group, Institute of Ophthalmology; University College London; London UK
| | - Lies De Groef
- Glaucoma and Retinal Degenerative Disease Research Group, Institute of Ophthalmology; University College London; London UK
- Neural Circuit Development and Regeneration Research Group, Department of Biology; University of Leuven; Leuven Belgium
| | - M. Francesca Cordeiro
- Glaucoma and Retinal Degenerative Disease Research Group, Institute of Ophthalmology; University College London; London UK
- Western Eye Hospital, Imperial College Healthcare National Health Service Trust; London UK
- Imperial College Ophthalmology Research Group, Department of Surgery and Cancer, Imperial College London; London UK
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Gerboni G, John SE, Rind GS, Ronayne SM, May CN, Oxley TJ, Grayden DB, Opie NL, Wong YT. Visual evoked potentials determine chronic signal quality in a stent-electrode endovascular neural interface. Biomed Phys Eng Express 2018. [DOI: 10.1088/2057-1976/aad714] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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He SB, Liu CY, Chen LD, Ye ZN, Zhang YP, Tang WG, Wang BD, Gao X. Meta-Analysis of Visual Evoked Potential and Parkinson's Disease. PARKINSON'S DISEASE 2018; 2018:3201308. [PMID: 30123489 PMCID: PMC6079328 DOI: 10.1155/2018/3201308] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 05/20/2018] [Accepted: 06/03/2018] [Indexed: 11/18/2022]
Abstract
BACKGROUND Previous studies suggested that visual evoked potential (VEP) was impaired in patients with Parkinson's disease (PD), but the results were inconsistent. METHODS We conducted a systematic review and meta-analysis to explore whether the VEP was significantly different between PD patients and healthy controls. Case-control studies of PD were selected through an electronic search of the databases PubMed, Embase, and the Cochrane Central Register of Controlled Trials. We calculated the pooled weighted mean differences (WMDs) and 95% confidence intervals (CIs) between individuals with PD and controls using the random-effects model. RESULTS Twenty case-control studies which met our inclusion criteria were included in the final meta-analysis. We found that the P100 latency in PD was significantly higher compared with healthy controls (pooled WMD = 6.04, 95% CI: 2.73 to 9.35, P=0.0003, n=20). However, the difference in the mean amplitude of P100 was not significant between the two groups (pooled WMD = 0.64, 95% CI: -0.06 to 1.33, P=0.07) based on 10 studies with the P100 amplitude values available. CONCLUSIONS The higher P100 latency of VEP was observed in PD patients, relative to healthy controls. Our findings suggest that electrophysiological changes and functional defect in the visual pathway of PD patients are important to our understanding of the pathophysiology of visual involvement in PD.
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Affiliation(s)
- Song-bin He
- Department of Neurology, Zhoushan Hospital, Wenzhou Medical University, Zhoushan 316021, China
| | - Chun-yan Liu
- Department of Critical Care Medicine, Huzhou Central Hospital, Huzhou 313000, China
| | - Lin-di Chen
- Department of Neurology, Zhoushan Hospital, Wenzhou Medical University, Zhoushan 316021, China
| | - Zhi-nan Ye
- Department of Neurology, Taizhou Municipal Hospital, Taizhou 318000, China
| | - Ya-ping Zhang
- Department of Neurology, Taizhou Municipal Hospital, Taizhou 318000, China
| | - Wei-guo Tang
- Department of Neurology, Zhoushan Hospital, Wenzhou Medical University, Zhoushan 316021, China
| | - Bin-da Wang
- Department of Neurology, Zhoushan Hospital, Wenzhou Medical University, Zhoushan 316021, China
| | - Xiang Gao
- Department of Nutritional Sciences, The Pennsylvania State University, USA
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Dai H, Jackson CR, Davis GL, Blakely RD, McMahon DG. Is dopamine transporter-mediated dopaminergic signaling in the retina a noninvasive biomarker for attention-deficit/ hyperactivity disorder? A study in a novel dopamine transporter variant Val559 transgenic mouse model. J Neurodev Disord 2017; 9:38. [PMID: 29281965 PMCID: PMC5745861 DOI: 10.1186/s11689-017-9215-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Accepted: 09/14/2017] [Indexed: 12/14/2022] Open
Abstract
Background Dopamine (DA) is a critical neuromodulator in the retina. Disruption of retinal DA synthesis and signaling significantly attenuates light-adapted, electroretinogram (ERG) responses, as well as contrast sensitivity and acuity. As these measures can be detected noninvasively, they may provide opportunities to detect disease processes linked to perturbed DA signaling. Recently, we identified a rare, functional DA transporter (DAT, SLC6A3) coding substitution, Ala559Val, in subjects with attention-deficit/hyperactivity disorder (ADHD), demonstrating that DAT Val559 imparts anomalous DA efflux (ADE) with attendant physiological, pharmacological, and behavioral phenotypes. To understand the broader impact of ADE on ADHD, noninvasive measures sensitive to DAT reversal are needed. Methods Here, we explored this question through ERG-based analysis of retinal light responses, as well as HPLC measurements of retinal DA in DAT Val559 mice. Results Male mice homozygous (HOM) for the DAT Val559 variant demonstrated increased, light-adapted ERG b-wave amplitudes compared to wild type (WT) and heterozygous (HET) mice, whereas dark-adapted responses were indistinguishable across genotypes. The elevated amplitude of the photopic light responses in HOM mice could be mimicked in WT mice by applying D1 and D4 DA receptor agonists and suppressed in HOM mice by introducing D4 antagonist, supporting elevated retinal DA signaling arising from ADE. Following the challenge with amphetamine, WT exhibited an increase in light-adapted response amplitudes, while HOM did not. Total retinal DA content was similar across genotypes. Interestingly, female DAT Val559 HOM animals revealed no significant difference in photopic ERG responses when compared with WT and HET littermates. Conclusions These data reveal that noninvasive, in vivo evaluation of retinal responses to light can reveal physiological signatures of ADE, suggesting a possible approach to the segregation of neurobehavioral disorders based on the DAT-dependent control of DA signaling.
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Affiliation(s)
- Heng Dai
- Department of Biological Sciences, Vanderbilt University, Box 35-1634 Station B, Nashville, TN, 37235-1634, USA
| | - Chad R Jackson
- Department of Biological Sciences, Vanderbilt University, Box 35-1634 Station B, Nashville, TN, 37235-1634, USA.,Present address: Defense Threat Reduction Agency, 8211 Terminal Road, Lorton, VA, 22079, USA
| | - Gwynne L Davis
- Department of Biomedical Sciences, Charles E. Schmidt College of Medicine and Brain Institute, Florida Atlantic University, Jupiter, FL, 33458, USA
| | - Randy D Blakely
- Department of Biomedical Sciences, Charles E. Schmidt College of Medicine and Brain Institute, Florida Atlantic University, Jupiter, FL, 33458, USA
| | - Douglas G McMahon
- Department of Biological Sciences, Vanderbilt University, Box 35-1634 Station B, Nashville, TN, 37235-1634, USA.
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Liu C, Zhang Y, Tang W, Wang B, Wang B, He S. Evoked potential changes in patients with Parkinson's disease. Brain Behav 2017; 7:e00703. [PMID: 28523237 PMCID: PMC5434200 DOI: 10.1002/brb3.703] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 02/06/2017] [Accepted: 03/03/2017] [Indexed: 11/09/2022] Open
Abstract
OBJECTIVE Patients with Parkinson's disease (PD) may have sensory dysfunction, and it can be more easily demonstrated through electrophysiologic testing. We aimed to explore whether the impairment of brainstem visual and auditory passageway exists in PD patients using visual evoked potential (VEP) and brainstem auditory evoked potential (BAEP) examinations. METHODS Forty-two PD cases and thirty controls participated in the study. All subjects underwent the VEP and BAEP examinations. The N75, P100, N145 latencies and P100 amplitude of VEP, the latencies of waves I, III, V and the interpeak latencies (IPL) of waves I-III, III-V, I-V were measured. RESULTS The N75, P100, N145 latencies of VEP, but not the amplitude of P100, were significantly longer in patients with PD than the control group (p < .05). The latencies of wave III and wave V, the IPL of III-V and I-V were all significantly increased compared with control subjects while no significant difference was noted in waves I and I-III IPL. CONCLUSION Our results found that brainstem visual and auditory passageway may be impaired in PD patients. SIGNIFICANCE VEP and BAEP can be served as sensitive measurements in helping prognosis and assessment the severity of the disease.
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Affiliation(s)
- Chunyan Liu
- Department of Neurology Zhoushan Hospital Wenzhou Medical University Zhoushan China
| | - Yaping Zhang
- Department of Neurology Zhoushan Hospital Wenzhou Medical University Zhoushan China
| | - Weiguo Tang
- Department of Neurology Zhoushan Hospital Wenzhou Medical University Zhoushan China
| | - Binda Wang
- Department of Neurology Zhoushan Hospital Wenzhou Medical University Zhoushan China
| | - Bona Wang
- Department of Neurology Zhoushan Hospital Wenzhou Medical University Zhoushan China
| | - Songbin He
- Department of Neurology Zhoushan Hospital Wenzhou Medical University Zhoushan China
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Zhu J, Shen B, Lu L, Lan W, Pan Y, Zhang L, Dong J, Wang M, Zhang L. Prevalence and risk factors for visual hallucinations in Chinese patients with Parkinson's disease. J Neurol Sci 2016; 372:471-476. [PMID: 27823833 DOI: 10.1016/j.jns.2016.10.043] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2016] [Revised: 08/29/2016] [Accepted: 10/15/2016] [Indexed: 11/17/2022]
Abstract
BACKGROUND AND PURPOSE Parkinson's disease (PD) patients frequently present visual hallucinations (VHs)·The determinants of VHs in Chinese PD patients remain largely unknown. The aim of this study was to illuminate the prevalence and clinical correlates of VHs in the Chinese population with PD. METHODS A total of 371 consecutive, idiopathic PD patients were recruited into the study. Patients were categorized as hallucinators and nonhallucinators according to Movement Disorder Society-sponsored revision of the Unified Parkinson's Disease Rating Scale (MDS-UPDRS). RESULTS VHs were observed in 72 (19.4%) patients. Among them, 26.4% of the hallucinators experienced minor hallucinations, and 73.6% had complex visual hallucinations. The age, disease duration, percentage of patients using dopamine agonists, UPDRS part III, Hoehn and Yahr (H-Y) stage, and Non-Motor Symptoms Questionnaire (NMS-Quest) score in hallucinators were significantly greater than in nonhallucinators (P<0.05). The Montreal Cognitive Assessment (MOCA) and PD Sleep Scale (PDSS) scores in nonhallucinators were significantly higher than in hallucinators (P<0.05). The Hamilton Depression Scale (HAMD) and Hamilton Anxiety Scale (HAMA) scores were not different between the hallucinators and nonhallucinators. The forward binary logistic regression model showed that disease duration, dopamine agonist use, sleep quality, and cognition were associated with VHs in PD patients. CONCLUSIONS Our results confirm the high prevalence of VHs in patients with PD. The VHs are associated with duration, dopamine agonist use, sleep quality, and cognition, and should trigger further inquiry by neurologists.
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Affiliation(s)
- Jun Zhu
- Department of Geriatric Neurology, Nanjing Brain Hospital Affiliated to Nanjing Medical University, Nanjing, Jiangsu, People's Republic of China; Clinical Medicine School, Nanjing Medical University, Nanjing, Jiangsu, People's Republic of China
| | - Bo Shen
- Department of Geriatric Neurology, Nanjing Brain Hospital Affiliated to Nanjing Medical University, Nanjing, Jiangsu, People's Republic of China; Clinical Medicine School, Nanjing Medical University, Nanjing, Jiangsu, People's Republic of China
| | - Liyu Lu
- Department of Geriatric Neurology, Nanjing Brain Hospital Affiliated to Nanjing Medical University, Nanjing, Jiangsu, People's Republic of China; Clinical Medicine School, Nanjing Medical University, Nanjing, Jiangsu, People's Republic of China
| | - Wenya Lan
- Department of Geriatric Neurology, Nanjing Brain Hospital Affiliated to Nanjing Medical University, Nanjing, Jiangsu, People's Republic of China
| | - Yang Pan
- Department of Geriatric Neurology, Nanjing Brain Hospital Affiliated to Nanjing Medical University, Nanjing, Jiangsu, People's Republic of China; Clinical Medicine School, Nanjing Medical University, Nanjing, Jiangsu, People's Republic of China
| | - Lili Zhang
- Department of Geriatric Neurology, Nanjing Brain Hospital Affiliated to Nanjing Medical University, Nanjing, Jiangsu, People's Republic of China
| | - Jingde Dong
- Department of Geriatric Neurology, Nanjing Brain Hospital Affiliated to Nanjing Medical University, Nanjing, Jiangsu, People's Republic of China
| | - Min Wang
- Department of Geriatric Neurology, Nanjing Brain Hospital Affiliated to Nanjing Medical University, Nanjing, Jiangsu, People's Republic of China
| | - Li Zhang
- Department of Geriatric Neurology, Nanjing Brain Hospital Affiliated to Nanjing Medical University, Nanjing, Jiangsu, People's Republic of China.
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Correlation Between Structural and Functional Retinal Changes in Parkinson Disease. J Neuroophthalmol 2015; 35:254-8. [DOI: 10.1097/wno.0000000000000240] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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Nowacka B, Lubiński W, Honczarenko K, Potemkowski A, Safranow K. Bioelectrical function and structural assessment of the retina in patients with early stages of Parkinson's disease (PD). Doc Ophthalmol 2015; 131:95-104. [PMID: 25972299 PMCID: PMC4567588 DOI: 10.1007/s10633-015-9503-0] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Accepted: 05/07/2015] [Indexed: 11/09/2022]
Abstract
Purpose
To determine bioelectrical function and structural changes of the retina in patients with early stages of Parkinson’s disease (PD). Materials and methods Thirty-eight eyes of 20 patients with early idiopathic PD and 38 eyes of 20 healthy age- and sex-matched controls were ophthalmologically examined, including assessment of distance best-corrected visual acuity (DBCVA), slit lamp examination of the anterior and posterior segment of the eye, evaluation of the eye structures: paramacular retinal thickness (RT) and retinal nerve fiber layer (RNFL) thickness with the aid of OCT, and the bioelectrical function by full-field electroretinogram (ERG). Additionally, PD patients were interviewed as to the presence of dopamine-dependent visual functions abnormalities. Results In patients with early PD, statistically significant changes in comparison with the control group were observed in ERG. They contained a reduction in mean amplitudes of the scotopic a-wave (rod–cone response), the scotopic oscillatory potentials (OPs)—OP2 and OP3, the photopic b-wave, and a reduction in the overall index (OP1 + OP2 + OP3) and a prolongation of mean peak times of the scotopic OP1, OP2, OP3, OP4 (p < 0.05). A questionnaire concerning abnormalities of dopamine-dependent visual functions revealed that PD patients with abnormal peak times of OP1, OP2, and OP3 reported non-specific visual disturbances more frequently in comparison with PD patients with normal peak times of OPs. Other analyzed parameters of ERG, DBCVA, RT, and RNFL did not significantly differ between patients with PD and the control group. Conclusion In patients with early PD, bioelectrical dysfunction of the retina was observed in the ERG test, probably as a result of dopamine deficiency in the retina. The results of our study indicate that ERG may also be a useful tool for understanding the reason for non-specific visual disturbances occurring in PD patients.
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Affiliation(s)
- Barbara Nowacka
- Department of Ophthalmology, Pomeranian Medical University, Powstancow Wlkp. 72, 70-111, Szczecin, Poland.
| | - Wojciech Lubiński
- Department of Ophthalmology, Pomeranian Medical University, Powstancow Wlkp. 72, 70-111, Szczecin, Poland
| | | | | | - Krzysztof Safranow
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University, Szczecin, Poland
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Aras S, Tanriover G, Aslan M, Yargicoglu P, Agar A. The role of nitric oxide on visual-evoked potentials in MPTP-induced Parkinsonism in mice. Neurochem Int 2014; 72:48-57. [DOI: 10.1016/j.neuint.2014.04.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Revised: 04/10/2014] [Accepted: 04/21/2014] [Indexed: 12/28/2022]
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Interocular amplitude and latency differences of pattern ERG and pattern VEP parameters. Optom Vis Sci 2014; 91:472-6. [PMID: 24492757 DOI: 10.1097/opx.0000000000000193] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
PURPOSE To determine the normal interocular differences in amplitudes and peak times of the pattern electroretinograms (PERGs) and pattern visual evoked potentials (PVEPs) and to investigate whether the PERG and PVEP parameters correspond in lateral dominance or whether the eye-side distributions of the functional parameters are similar. METHODS The PERGs and PVEPs were recorded in healthy subjects (N = 77) according to the standards of the International Society for Clinical Electrophysiology of Vision, with the modification of the check size of the PERG to 0.5 degrees. This allows stimulation of the macular ganglion cells and their corresponding visual pathways in healthy subjects. RESULTS Comparison of the averaged higher and lower response amplitudes and the shorter and longer response peak times showed significant differences (p < 0.001) in both the PERG and the PVEP parameters (median [5 to 95%]): the P50 (1.92% [0 to 5.48%]) and N95 (2.06% [0 to 13.95%]) peak times and the P50 (11.82% [1.32 to 29.93%) and N95 (9.45% [1.17 to 30.38%]) amplitudes of the PERGs and the P100 (1.04% [0 to 4.15%]) and N135 (1.96% [0 to 12.36%]) peak times and the P100 (9.86% [1.26 to 29.76%]) and N135 (11.19% [1.18 to 29.99%]) amplitudes of the PVEPs. No significant correlation was found concerning the eye dominance of the PERG and PVEP parameters. CONCLUSIONS Our results reveal a significant interocular difference on PERG and PVEP recording, but this could not be ascribed to the anatomy of the retina and related visual pathways. If the difference between the eyes is not taken into account, misinterpretation may occur in a pathological process.
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Roth NM, Saidha S, Zimmermann H, Brandt AU, Isensee J, Benkhellouf-Rutkowska A, Dornauer M, Kühn AA, Müller T, Calabresi PA, Paul F. Photoreceptor layer thinning in idiopathic Parkinson's disease. Mov Disord 2014; 29:1163-70. [DOI: 10.1002/mds.25896] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Revised: 02/20/2014] [Accepted: 03/03/2014] [Indexed: 11/09/2022] Open
Affiliation(s)
- Nicolas M. Roth
- NeuroCure Clinical Research Center; Charité-Universitätsmedizin Berlin; Germany
| | - Shiv Saidha
- Department of Neurology; Beaumont University Hospital; Republic of Ireland
- Department of Neurology; John Hopkins School of Medicine; Baltimore Maryland USA
| | - Hanna Zimmermann
- NeuroCure Clinical Research Center; Charité-Universitätsmedizin Berlin; Germany
| | - Alexander U. Brandt
- NeuroCure Clinical Research Center; Charité-Universitätsmedizin Berlin; Germany
| | - Justine Isensee
- NeuroCure Clinical Research Center; Charité-Universitätsmedizin Berlin; Germany
| | | | - Matthias Dornauer
- NeuroCure Clinical Research Center; Charité-Universitätsmedizin Berlin; Germany
| | - Andrea A. Kühn
- NeuroCure Clinical Research Center; Charité-Universitätsmedizin Berlin; Germany
- Department of Neurology; Charité-Universitätsmedizin Berlin; Germany
| | - Thomas Müller
- Department of Neurology; St. Joseph Hospital; Berlin Germany
| | - Peter A. Calabresi
- Department of Neurology; John Hopkins School of Medicine; Baltimore Maryland USA
| | - Friedemann Paul
- NeuroCure Clinical Research Center; Charité-Universitätsmedizin Berlin; Germany
- Department of Neurology; Charité-Universitätsmedizin Berlin; Germany
- Experimental and Clinical Research Center; Charité-Universitätsmedizin Berlin and Max-Delbrück-Center for Molecular Medicine; Berlin Germany
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Popova E. Role of dopamine in distal retina. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2014; 200:333-58. [PMID: 24728309 DOI: 10.1007/s00359-014-0906-2] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Revised: 03/24/2014] [Accepted: 03/25/2014] [Indexed: 01/11/2023]
Abstract
Dopamine is the most abundant catecholamine in the vertebrate retina. Despite the description of retinal dopaminergic cells three decades ago, many aspects of their function in the retina remain unclear. There is no consensus among the authors about the stimulus conditions for dopamine release (darkness, steady or flickering light) as well as about its action upon the various types of retinal cells. Many contradictory results exist concerning the dopamine effect on the gross electrical activity of the retina [reflected in electroretinogram (ERG)] and the receptors involved in its action. This review summarized current knowledge about the types of the dopaminergic neurons and receptors in the retina as well as the effects of dopamine receptor agonists and antagonists on the light responses of photoreceptors, horizontal and bipolar cells in both nonmammalian and mammalian retina. Special focus of interest concerns their effects upon the diffuse ERG as a useful tool for assessment of the overall function of the distal retina. An attempt is made to reveal some differences between the dopamine actions upon the activity of the ON versus OFF channel in the distal retina. The author has included her own results demonstrating such differences.
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Affiliation(s)
- E Popova
- Department of Physiology, Medical Faculty, Medical University, 1431, Sofia, Bulgaria,
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Visual contrast sensitivity in major depressive disorder. J Psychosom Res 2013; 75:83-6. [PMID: 23751244 DOI: 10.1016/j.jpsychores.2013.03.008] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Revised: 03/12/2013] [Accepted: 03/15/2013] [Indexed: 11/23/2022]
Abstract
OBJECTIVE Through the eyes of those depressed, the world may appear dull and gray. Visual contrast sensitivity has recently been reported to be lower in depressed patients compared to healthy controls. We aimed to examine the consistency of this finding and to explore the underlying retinal electrophysiology. METHODS Twenty subjects with major depressive disorder and 20 matched healthy controls were studied. Pattern electroretinogram (PERG) and subjective visual contrast test were used to assess visual contrast sensitivity. Full-field electroretinography (ffERG) was additionally used to assess retinal neurophysiology. Depression was diagnosed based on the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) and depression severity was measured using standard psychometric scales. RESULTS Visual contrast sensitivity was significantly lower in depressed patients compared to controls based on the Landolt C visual contrast test, but no difference was found between groups using PERG and ffERG. Greater severity of depressive symptoms correlated (r=0.49, p=0.001) with poorer visual contrast sensitivity. CONCLUSIONS Depressed subjects had reduced visual contrast discrimination performance, but this finding could not be consistently determined using PERG. The neurobiological link between major depressive disorder and visual contrast sensitivity warrants further investigation.
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Berardelli A, Wenning GK, Antonini A, Berg D, Bloem BR, Bonifati V, Brooks D, Burn DJ, Colosimo C, Fanciulli A, Ferreira J, Gasser T, Grandas F, Kanovsky P, Kostic V, Kulisevsky J, Oertel W, Poewe W, Reese JP, Relja M, Ruzicka E, Schrag A, Seppi K, Taba P, Vidailhet M. EFNS/MDS-ES/ENS [corrected] recommendations for the diagnosis of Parkinson's disease. Eur J Neurol 2013; 20:16-34. [PMID: 23279440 DOI: 10.1111/ene.12022] [Citation(s) in RCA: 323] [Impact Index Per Article: 29.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2012] [Accepted: 09/18/2012] [Indexed: 01/24/2023]
Abstract
BACKGROUND A Task Force was convened by the EFNS/MDS-ES Scientist Panel on Parkinson's disease (PD) and other movement disorders to systemically review relevant publications on the diagnosis of PD. METHODS Following the EFNS instruction for the preparation of neurological diagnostic guidelines, recommendation levels have been generated for diagnostic criteria and investigations. RESULTS For the clinical diagnosis, we recommend the use of the Queen Square Brain Bank criteria (Level B). Genetic testing for specific mutations is recommended on an individual basis (Level B), taking into account specific features (i.e. family history and age of onset). We recommend olfactory testing to differentiate PD from other parkinsonian disorders including recessive forms (Level A). Screening for pre-motor PD with olfactory testing requires additional tests due to limited specificity. Drug challenge tests are not recommended for the diagnosis in de novo parkinsonian patients. There is an insufficient evidence to support their role in the differential diagnosis between PD and other parkinsonian syndromes. We recommend an assessment of cognition and a screening for REM sleep behaviour disorder, psychotic manifestations and severe depression in the initial evaluation of suspected PD cases (Level A). Transcranial sonography is recommended for the differentiation of PD from atypical and secondary parkinsonian disorders (Level A), for the early diagnosis of PD and in the detection of subjects at risk for PD (Level A), although the technique is so far not universally used and requires some expertise. Because specificity of TCS for the development of PD is limited, TCS should be used in conjunction with other screening tests. Conventional magnetic resonance imaging and diffusion-weighted imaging at 1.5 T are recommended as neuroimaging tools that can support a diagnosis of multiple system atrophy (MSA) or progressive supranuclear palsy versus PD on the basis of regional atrophy and signal change as well as diffusivity patterns (Level A). DaTscan SPECT is registered in Europe and the United States for the differential diagnosis between degenerative parkinsonisms and essential tremor (Level A). More specifically, DaTscan is indicated in the presence of significant diagnostic uncertainty such as parkinsonism associated with neuroleptic exposure and atypical tremor manifestations such as isolated unilateral postural tremor. Studies of [(123) I]MIBG/SPECT cardiac uptake may be used to identify patients with PD versus controls and MSA patients (Level A). All other SPECT imaging studies do not fulfil registration standards and cannot be recommended for routine clinical use. At the moment, no conclusion can be drawn as to diagnostic efficacy of autonomic function tests, neurophysiological tests and positron emission tomography imaging in PD. CONCLUSIONS The diagnosis of PD is still largely based on the correct identification of its clinical features. Selected investigations (genetic, olfactory, and neuroimaging studies) have an ancillary role in confirming the diagnosis, and some of them could be possibly used in the near future to identify subjects in a pre-symptomatic phase of the disease.
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Affiliation(s)
- A Berardelli
- Dipartimento di Neurologia e Psichiatria and IRCCS NEUROMED Institute, Sapienza, Università di Roma, Rome, Italy.
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Foveal vision is impaired in Parkinson's disease. Parkinsonism Relat Disord 2013; 19:1-14. [DOI: 10.1016/j.parkreldis.2012.07.012] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2010] [Revised: 07/16/2012] [Accepted: 07/21/2012] [Indexed: 11/23/2022]
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Rodriguez-Mena D, Almarcegui C, Dolz I, Pablo LE, Garcia-Martin E. Application of electrophysiological tests in the study of neurological diseases with visual involvement. ACTA ACUST UNITED AC 2012; 87:311-4. [PMID: 23021227 DOI: 10.1016/j.oftal.2012.09.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2012] [Accepted: 08/15/2012] [Indexed: 11/29/2022]
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Tsironi EE, Dastiridou A, Katsanos A, Dardiotis E, Veliki S, Patramani G, Zacharaki F, Ralli S, Hadjigeorgiou GM. Perimetric and retinal nerve fiber layer findings in patients with Parkinson's disease. BMC Ophthalmol 2012; 12:54. [PMID: 23031247 PMCID: PMC3515471 DOI: 10.1186/1471-2415-12-54] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Accepted: 09/25/2012] [Indexed: 11/13/2022] Open
Abstract
Background Visual dysfunction is common in Parkinson’s disease (PD). It remains, however, unknown whether it is related to structural alterations of the retina. The aim of this study is to compare visual field (VF) findings and circumpapillary retinal nerve fiber layer (RNFL) thickness in a series of PD patients and normal controls, in order to assess possible retinal anatomical changes and/or functional damage associated with PD. Methods PD patients and controls were recruited and underwent VF testing with static automated perimetry and RNFL examination with optical coherence tomography (OCT). Cognitive performance using Mini Mental State Examination (MMSE), PD staging using modified Hoehn and Yahr (H-Y) scale and duration of the disease was recorded in PD patients. Results One randomly selected eye from each of 24 patients and 24 age-matched controls was included. OCT RNFL thickness analysis revealed no difference in the inferior, superior, nasal or temporal sectors between the groups. The average peripapillary RNFL was also similar in the two groups. However, perimetric indices of generalized sensitivity loss (mean deviation) and localized scotomas (pattern standard deviation) were worse in patients with PD compared to controls (p < 0.01). 73% of eyes of PD patients had glaucomatous-like asymmetrical hemifield defects with abnormal Glaucoma Hemifield Test and various combinations of arcuate defects (n = 12), nasal steps (n = 11) and paracentral scotomas (n = 16). Bilateral defects were found in 14 patients (58%). No correlation was found between VF indices and MMSE or H-Y scores. Conclusion PD patients may demonstrate glaucomatous-like perimetric defects even in the absence of decreased RNFL thickness.
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Affiliation(s)
- Evangelia E Tsironi
- Department of Ophthalmology, University Hospital of Larissa, Faculty of Medicine, University of Thessaly, Mezourlo 41222 Larissa, Greece.
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Time-resolved influences of functional DAT1 and COMT variants on visual perception and post-processing. PLoS One 2012; 7:e41552. [PMID: 22844499 PMCID: PMC3402385 DOI: 10.1371/journal.pone.0041552] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2012] [Accepted: 06/26/2012] [Indexed: 11/19/2022] Open
Abstract
Background Dopamine plays an important role in orienting and the regulation of selective attention to relevant stimulus characteristics. Thus, we examined the influences of functional variants related to dopamine inactivation in the dopamine transporter (DAT1) and catechol-O-methyltransferase genes (COMT) on the time-course of visual processing in a contingent negative variation (CNV) task. Methods 64-channel EEG recordings were obtained from 195 healthy adolescents of a community-based sample during a continuous performance task (A-X version). Early and late CNV as well as preceding visual evoked potential components were assessed. Results Significant additive main effects of DAT1 and COMT on the occipito-temporal early CNV were observed. In addition, there was a trend towards an interaction between the two polymorphisms. Source analysis showed early CNV generators in the ventral visual stream and in frontal regions. There was a strong negative correlation between occipito-temporal visual post-processing and the frontal early CNV component. The early CNV time interval 500–1000 ms after the visual cue was specifically affected while the preceding visual perception stages were not influenced. Conclusions Late visual potentials allow the genomic imaging of dopamine inactivation effects on visual post-processing. The same specific time-interval has been found to be affected by DAT1 and COMT during motor post-processing but not motor preparation. We propose the hypothesis that similar dopaminergic mechanisms modulate working memory encoding in both the visual and motor and perhaps other systems.
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Esteve-Rudd J, Fernández-Sánchez L, Lax P, De Juan E, Martín-Nieto J, Cuenca N. Rotenone induces degeneration of photoreceptors and impairs the dopaminergic system in the rat retina. Neurobiol Dis 2011; 44:102-15. [DOI: 10.1016/j.nbd.2011.06.009] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2011] [Revised: 05/24/2011] [Accepted: 06/16/2011] [Indexed: 12/21/2022] Open
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Cardoso EF, Fregni F, Maia FM, Melo LM, Sato JR, Cruz AC, Bianchi ET, Fernandes DB, Monteiro MLR, Barbosa ER, Amaro E. Abnormal visual activation in Parkinson's disease patients. Mov Disord 2010; 25:1590-6. [DOI: 10.1002/mds.23101] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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Gelmi C, Sandrini G, Martignoni E, Bruno A, Nappiand G, Trimarchi F. Electroretinograms and visual evoked cortical potentials in Parkinsonian patients with or without L-Dopa treatment. Neuroophthalmology 2009. [DOI: 10.3109/01658109209058128] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Abstract
As a more complete picture of the clinical phenotype of Parkinson's disease emerges, non-motor symptoms have become increasingly studied. Prominent among these non-motor phenomena are mood disturbance, cognitive decline and dementia, sleep disorders, hyposmia and autonomic failure. In addition, visual symptoms are common, ranging from complaints of dry eyes and reading difficulties, through to perceptual disturbances (feelings of presence and passage) and complex visual hallucinations. Such visual symptoms are a considerable cause of morbidity in Parkinson's disease and, with respect to visual hallucinations, are an important predictor of cognitive decline as well as institutional care and mortality. Evidence exists of visual dysfunction at several levels of the visual pathway in Parkinson's disease. This includes psychophysical, electrophysiological and morphological evidence of disruption of retinal structure and function, in addition to disorders of 'higher' (cortical) visual processing. In this review, we will draw together work from animal and human studies in an attempt to provide an insight into how Parkinson's disease affects the retina and how these changes might contribute to the visual symptoms experienced by patients.
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Affiliation(s)
- Neil K Archibald
- Clinical Research Fellow, Clinical Ageing Research Unit, Newcastle University, Campus for Ageing and Vitality, Newcastle upon Tyne, NE4 5PL, UK.
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Correlation between retinal morphological and functional findings and clinical severity in Parkinson’s disease. Doc Ophthalmol 2007; 116:137-46. [DOI: 10.1007/s10633-007-9091-8] [Citation(s) in RCA: 152] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2007] [Accepted: 10/11/2007] [Indexed: 02/05/2023]
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Brandies R, Yehuda S. The possible role of retinal dopaminergic system in visual performance. Neurosci Biobehav Rev 2007; 32:611-56. [PMID: 18061262 DOI: 10.1016/j.neubiorev.2007.09.004] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2007] [Revised: 09/23/2007] [Accepted: 09/28/2007] [Indexed: 10/22/2022]
Abstract
It is a well-known fact that the retina is one of the tissues in the body, which is richest in dopamine (DA), yet the role of this system in various visual functions remains unclear. We have identified 13 types of DA retinal pathologies, and 15 visual functions. The pathologies were arranged in this review on a net grid, where one axis was "age" (i.e., from infancy to old age) and the other axis the level of retinal DA (i.e., from DA deficiency to DA excess, from Parkinson disorder to Schizophrenia). The available data on visual dysfunction(s) is critically presented for each of the DA pathologies. Special effort was made to evaluate whether the site of DA malfunction in the different DA pathologies and visual function is at retinal level or in higher brain centers. The mapping of DA and visual pathologies demonstrate the pivot role of retinal DA in mediating visual functions and also indicate the "missing links" in our understanding of the mechanisms underlying these relationships.
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Affiliation(s)
- R Brandies
- Department of Pharmacology, Israel Institute for Biological Research, P.O. Box 19, Ness Ziona 74100, Israel
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Palmowski-Wolfe AM, Perez MT, Behnke S, Fuss G, Martziniak M, Ruprecht KW. Influence of Dopamine Deficiency in Early Parkinson’s Disease on the Slow Stimulation Multifocal-ERG. Doc Ophthalmol 2006; 112:209-15. [PMID: 16791744 DOI: 10.1007/s10633-006-0008-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/08/2006] [Indexed: 10/24/2022]
Abstract
PURPOSE In animal studies intravitreal injection of tetrodotoxin (TTX) results in mfERG waveform changes similar to those observed in glaucoma. As TTX blocks amacrine as well as ganglion cells, there is still a question regarding the underlying cell population responsible for these changes in waveform. In an attempt to assess the contribution of the amacrine cells to these changes, a mfERG was obtained from patients with Parkinson's disease as some amacrine cells are mediated by dopamine, a substance lacking in Parkinson's. METHODS Eight patients with early Parkinson's disease underwent ophthalmologic examination, testing of contrast sensitivity and electrophysiological examination according to ISCEV standard at least 12 h following their last medication with Dopamine. A slow stimulation mfERG was obtained with a stimulus base interval of 53.3 ms and with a stimulus base interval of 106.6 ms. During MF-ERG recordings 103 hexagons stimulated the central 50 deg of the retina simultaneously and independently (m-sequence 2(13), L(max): 200 cd/m(2), approximately 100% contrast). RESULTS Contrast sensitivity and ISCEV standard electrophysiological testing was unremarkable. When the mfERG was analyzed, only four patients had an adequate signal-to-noise ratio to allow further data analysis - one of whom was diagnosed with a multi system atrophy in retrospect. The first order response component was analyzed at a filter setting of 10-300 Hz and at 100-300 Hz (OPs) and compared to mfERGs of a control group. On average, in patients, the amplitude of N1P1 was slightly lower in the central and nasal response averages. When the three OPs at a latency of 72-89 ms were analyzed in the 53.3 ms base interval recording, the most marked difference in amplitude was observed in the superior nasal response average of the first OP. Here a mean amplitude of 1.3 nV/deg(2) in patients compared to a mean amplitude of 1.9 nV/deg(2) in the control group (P: 0.08). DISCUSSION In contrast to our previous findings in NTG, there was a consistent presence of three OPs. Under the stimulus conditions applied, we did not find an influence of dopaminergic amacrine cells on the mfERG in our patients with moderate stages of Parkinsion's. The difficulties in obtaining an adequate signal-to noise ratio due to e.g. muscle artifacts even in Parkinson patients of moderate disease stages render a success of mfERG recording in patients with more advanced stages unlikely. The question of the influence of dopaminergic amacrine cells on the mfERG could possibly be addressed using MPDT in animal research.
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Matsui H, Udaka F, Tamura A, Oda M, Kubori T, Nishinaka K, Kameyama M. The relation between visual hallucinations and visual evoked potential in Parkinson disease. Clin Neuropharmacol 2005; 28:79-82. [PMID: 15795550 DOI: 10.1097/01.wnf.0000157066.50948.65] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE The pathophysiology of hallucinations in Parkinson disease is poorly understood. This study investigated the relation between visual hallucination and visual evoked potentials (VEPs) in Parkinson disease. METHODS Nineteen patients with Parkinson disease were studied. The authors divided patients into 2 groups: patients with visual hallucinations (VH group) and those without visual hallucinations (no-VH group). VEPs using a checkerboard stimulus were recorded under a drug-free state. RESULTS On multivariate regression analysis, only the average P100 latency was selected and remained significant after the backward elimination method. CONCLUSION The authors demonstrated a close association between visual hallucinations and elongated VEP latency in Parkinson disease. VEPs may become one of the predictors for visual hallucination.
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Affiliation(s)
- Hideaki Matsui
- Department of Neurology, Sumitomo Hospital, Osaka, Japan.
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Eisenhofer G, Kopin IJ, Goldstein DS. Catecholamine metabolism: a contemporary view with implications for physiology and medicine. Pharmacol Rev 2005; 56:331-49. [PMID: 15317907 DOI: 10.1124/pr.56.3.1] [Citation(s) in RCA: 639] [Impact Index Per Article: 33.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
This article provides an update about catecholamine metabolism, with emphasis on correcting common misconceptions relevant to catecholamine systems in health and disease. Importantly, most metabolism of catecholamines takes place within the same cells where the amines are synthesized. This mainly occurs secondary to leakage of catecholamines from vesicular stores into the cytoplasm. These stores exist in a highly dynamic equilibrium, with passive outward leakage counterbalanced by inward active transport controlled by vesicular monoamine transporters. In catecholaminergic neurons, the presence of monoamine oxidase leads to formation of reactive catecholaldehydes. Production of these toxic aldehydes depends on the dynamics of vesicular-axoplasmic monoamine exchange and enzyme-catalyzed conversion to nontoxic acids or alcohols. In sympathetic nerves, the aldehyde produced from norepinephrine is converted to 3,4-dihydroxyphenylglycol, not 3,4-dihydroxymandelic acid. Subsequent extraneuronal O-methylation consequently leads to production of 3-methoxy-4-hydroxyphenylglycol, not vanillylmandelic acid. Vanillylmandelic acid is instead formed in the liver by oxidation of 3-methoxy-4-hydroxyphenylglycol catalyzed by alcohol and aldehyde dehydrogenases. Compared to intraneuronal deamination, extraneuronal O-methylation of norepinephrine and epinephrine to metanephrines represent minor pathways of metabolism. The single largest source of metanephrines is the adrenal medulla. Similarly, pheochromocytoma tumor cells produce large amounts of metanephrines from catecholamines leaking from stores. Thus, these metabolites are particularly useful for detecting pheochromocytomas. The large contribution of intraneuronal deamination to catecholamine turnover, and dependence of this on the vesicular-axoplasmic monoamine exchange process, helps explain how synthesis, release, metabolism, turnover, and stores of catecholamines are regulated in a coordinated fashion during stress and in disease states.
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Affiliation(s)
- Graeme Eisenhofer
- Clinical Neurocardiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, 10 Center Dr., MSC-1620, Bethesda, MD 20892-1620, USA.
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Wylie SA, Stout JC, Bashore TR. Activation of conflicting responses in Parkinson's disease: evidence for degrading and facilitating effects on response time. Neuropsychologia 2005; 43:1033-43. [PMID: 15769489 DOI: 10.1016/j.neuropsychologia.2004.10.008] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2004] [Revised: 10/14/2004] [Accepted: 10/21/2004] [Indexed: 11/29/2022]
Abstract
Response selection often occurs in a context of competition among conflicting responses. According to recent models, the basal ganglia may play an integral role in resolving this competition by focusing the selection and inhibition of responses. We hypothesized that basal ganglia dysfunction produced by Parkinson's disease (PD) disrupts selection among conflicting responses. Using a version of the Eriksen flanker task, we tested the specific prediction that individuals with PD would experience greater response interference when distractors in the visual field activate a response that conflicts with the target response. In addition, we investigated whether greater response interference induced by these distractors could actually reduce normal response time costs in PD when the task required production of the response opposite the target. Compared to 16 healthy controls (HC), 16 individuals with PD showed an exacerbated slowing when target and distracting stimuli corresponded to conflicting responses. No group differences occurred when targets and distractors corresponded to the same response. Furthermore, the slowing induced by the distractors was reduced in both groups, but more so in PD, when execution of a response opposite the target response (i.e. incompatible response) was required. Moreover, among individuals with PD, the magnitude of the interference produced by the distractors was related to clinical ratings of bradykinesia. These findings are consistent with the hypothesis that basal ganglia dysfunction due to Parkinson's disease disrupts processes that resolve response conflict.
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Affiliation(s)
- Scott A Wylie
- Department of Neurology, University of Virginia, Charlottesville, VA, USA
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Abstract
The four most common sight-threatening conditions in older adults in North America are cataract, ARM, glaucoma, and diabetic retinopathy. Even in their moderate stages, these conditions cause visual sensory impairments and reductions in health-related quality of life, including difficulties in daily tasks and psychosocial problems. Many older adults are free from these conditions, yet still experience a variety of visual perceptual problems resulting from aging-related changes in the optics of the eye and degeneration of the visual neural pathways. These problems consist of impairments in visual acuity, contrast sensitivity, color discrimination, temporal sensitivity, motion perception, peripheral visual field sensitivity, and visual processing speed. PD causes a progressive loss of dopaminergic cells predominantly in the retina and possibly in other areas of the visual system. This retinal dopamine deficiency produces selective spatial-temporal abnormalities in retinal ganglion cell function, probably arising from altered receptive field organization in the PD retina. The cortical degeneration characteristics of AD, including neurofibrillary tangles and neuritic plaques, also are present in the visual cortical areas, especially in the visual association areas. The most prominent electrophysiologic change in AD is a delay in the P2 component of the flash VEP. Deficits in higher-order visual abilities typically are compromised in AD, including problems with visual attention, perceiving structure from motion, visual memory, visual learning, reading, and object and face perception. There have been reports of a visual variant of AD in which these types of visual problems are the initial and most prominent signs of the disease. Visual sensory impairments (e.g., contrast sensitivity or achromatopsia) also have been reported but are believed more reflective of cortical disturbances than of AD-associated optic neuropathy.
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Affiliation(s)
- Gregory R Jackson
- Department of Ophthalmology, School of Medicine, University of Alabama at Birmingham, 700 South 18th Street, Suite 609, Birmingham, AL 35294-0009, USA.
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