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Li J, Guo Y, Li Q, Miao K, Wang C, Zhang D, Tian C, Zhang S. Presence of White Matter Lesions Associated with Diabetes-Associated Cognitive Decline in Male Rat Models of Pre-Type 2 Diabetes. Med Sci Monit 2019; 25:9679-9689. [PMID: 31848329 PMCID: PMC6930701 DOI: 10.12659/msm.918557] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND The aim of this study was to determine the association between white matter lesions (WML) and diabetes-associated cognitive decline (DACD) in rat models of type 2 diabetes (T2DM). MATERIAL AND METHODS Sixty Sprague-Dawley male rats were divided into 4 groups: control, control+metformin, T2DM, and T2DM+metformin groups. The T2DM groups were fed a diet high in fat and glucose to induce impaired glucose tolerance (IGT) and then were injected with streptozotocin to induce T2DM. The Morris water maze test was used to evaluate cognitive function. Brain diffusion tensor imaging scans were performed for WML. The expression of myelin basic protein (MBP), oligodendrocyte transcription factor 1 (OLIG1), and OLIG2 (markers of brain damage and repair) was determined using immunofluorescence. After IGT, the fractional anisotropy (FA) values of the right thalamus area were significantly lower in both T2DM groups compared with controls. RESULTS Eight weeks after streptozotocin injection, the FA values of the thalamus were lower in the T2DM (bilateral thalamus) group and T2DM+metformin (left thalamus) group than in controls, while the FA values in the left thalamus area were lower in the T2DM+metformin group than in the control and control+metformin groups. The maze escape latency was longer and the number of rats passing through the platform was smaller in the T2DM and T2DM+metformin groups than in the control group. MBP levels were lower and OLIG1 and OLIG2 levels were higher in both T2DM groups than in controls. CONCLUSIONS WML is associated with DACD and appears before the onset of T2DM and signs of DACD and plays a role in diabetes-associated cognitive decline. Metformin reduces WMLs but does not rescue cognitive dysfunction.
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Affiliation(s)
- Jun Li
- Department of Endocrinology, The Second Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China (mainland)
| | - Yafei Guo
- Department of Radiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China (mainland)
| | - Qingju Li
- Department of Endocrinology, The Second Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China (mainland)
| | - Keke Miao
- Department of Breast Surgery, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China (mainland)
| | - Chongxian Wang
- Department of Endocrinology, The Second Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China (mainland)
| | - Dongming Zhang
- Department of Endocrinology, The Second Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China (mainland)
| | - Chenguang Tian
- Department of Endocrinology, The Second Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China (mainland)
| | - Suhe Zhang
- Department of Endocrinology, The Second Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China (mainland)
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Smirni D, Smirni P, Di Martino G, Cipolotti L, Oliveri M, Turriziani P. Standardization and validation of a parallel form of the verbal and non-verbal recognition memory test in an Italian population sample. Neurol Sci 2018; 39:1391-1399. [PMID: 29728938 DOI: 10.1007/s10072-018-3433-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Accepted: 04/26/2018] [Indexed: 11/30/2022]
Abstract
In the neuropsychological assessment of several neurological conditions, recognition memory evaluation is requested. Recognition seems to be more appropriate than recall to study verbal and non-verbal memory, because interferences of psychological and emotional disorders are less relevant in the recognition than they are in recall memory paradigms. In many neurological disorders, longitudinal repeated assessments are needed to monitor the effectiveness of rehabilitation programs or pharmacological treatments on the recovery of memory. In order to contain the practice effect in repeated neuropsychological evaluations, it is necessary the use of parallel forms of the tests. Having two parallel forms of the same test, that kept administration procedures and scoring constant, is a great advantage in both clinical practice, for the monitoring of memory disorder, and in experimental practice, to allow the repeated evaluation of memory on healthy and neurological subjects. First aim of the present study was to provide normative values in an Italian sample (n = 160) for a parallel form of a verbal and non-verbal recognition memory battery. Multiple regression analysis revealed significant effects of age and education on recognition memory performance, whereas sex did not reach a significant probability level. Inferential cutoffs have been determined and equivalent scores computed. Secondly, the study aimed to validate the equivalence of the two parallel forms of the Recognition Memory Test. The correlations analyses between the total scores of the two versions of the test and correlation between the three subtasks revealed that the two forms are parallel and the subtasks are equivalent for difficulty.
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Affiliation(s)
- Daniela Smirni
- Dipartimento di Scienze Psicologiche, Pedagogiche e della Formazione, Università degli Studi di Palermo, viale delle Scienze, Ed.15, 90128, Palermo, Italy. .,NeuroTeam Life and Science, Palermo, Italy.
| | - Pietro Smirni
- Dipartimento di Scienze della Formazione, Università degli Studi di Catania, Catania, Italy
| | | | - Lisa Cipolotti
- Department of Neuropsychology, National Hospital for Neurology and Neurosurgery, Queen Square, London, UK
| | - Massimiliano Oliveri
- Dipartimento di Scienze Psicologiche, Pedagogiche e della Formazione, Università degli Studi di Palermo, viale delle Scienze, Ed.15, 90128, Palermo, Italy.,NeuroTeam Life and Science, Palermo, Italy
| | - Patrizia Turriziani
- Dipartimento di Scienze Psicologiche, Pedagogiche e della Formazione, Università degli Studi di Palermo, viale delle Scienze, Ed.15, 90128, Palermo, Italy.,NeuroTeam Life and Science, Palermo, Italy
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Diffusion tensor tractography of the mammillothalamic tract in the human brain using a high spatial resolution DTI technique. Sci Rep 2018; 8:5229. [PMID: 29588461 PMCID: PMC5869722 DOI: 10.1038/s41598-018-23452-w] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Accepted: 02/19/2018] [Indexed: 02/07/2023] Open
Abstract
The mammillary bodies as part of the hypothalamic nuclei are in the central limbic circuitry of the human brain. The mammillary bodies are shown to be directly or indirectly connected to the amygdala, hippocampus, and thalami as the major gray matter structures of the human limbic system. Although it is not primarily considered as part of the human limbic system, the thalamus is shown to be involved in many limbic functions of the human brain. The major direct connection of the thalami with the hypothalamic nuclei is known to be through the mammillothalamic tract. Given the crucial role of the mammillothalamic tracts in memory functions, diffusion tensor imaging may be helpful in better visualizing the surgical anatomy of this pathway noninvasively. This study aimed to investigate the utility of high spatial resolution diffusion tensor tractography for mapping the trajectory of the mammillothalamic tract in the human brain. Fifteen healthy adults were studied after obtaining written informed consent. We used high spatial resolution diffusion tensor imaging data at 3.0 T. We delineated, for the first time, the detailed trajectory of the mammillothalamic tract of the human brain using deterministic diffusion tensor tractography.
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Silva SM, Cunha-Cabral D, Andrade JP. Neurosurgical relevance of the dissection of the diencephalic white matter tracts using the Klingler technique. Clin Neurol Neurosurg 2017; 156:35-40. [DOI: 10.1016/j.clineuro.2017.03.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 02/27/2017] [Accepted: 03/01/2017] [Indexed: 01/08/2023]
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Acute Amnesia due to Isolated Mammillary Body Infarct. J Stroke Cerebrovasc Dis 2015; 24:e303-5. [DOI: 10.1016/j.jstrokecerebrovasdis.2015.06.038] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Revised: 05/25/2015] [Accepted: 06/27/2015] [Indexed: 11/24/2022] Open
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Kwon HG, Lee HD, Jang SH. Injury of the mammillothalamic tract in patients with thalamic hemorrhage. Front Hum Neurosci 2014; 8:259. [PMID: 24795611 PMCID: PMC4000991 DOI: 10.3389/fnhum.2014.00259] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Accepted: 04/07/2014] [Indexed: 11/15/2022] Open
Abstract
Objective: Injury of the mammillothalamic tract (MTT) has been suggested as one of the plausible pathogenic mechanisms of memory impairment in patients with thalamic hemorrhage; however, it has not been clearly demonstrated so far. We attempted to investigate whether injury of the MTT documented by diffusion tensor tractography following thalamic hemorrhage correlates with cognitive impairment. Methods: We recruited 22 patients with a thalamic hemorrhage and 20 control subjects. MTTs were reconstructed using the probabilistic tractography method. Patients were classified into two subgroups: reconstructed group, patients whose MTT was reconstructed in the affected hemisphere, and non-reconstructed group, patients whose MTT was not reconstructed. Results: Mammillothalamic tract was reconstructed in 5 (22.7%, reconstructed group) patients in the affected hemisphere and was not reconstructed in the remaining 17 patients (77.3%, non-reconstructed group). In addition, the MTT was not reconstructed even in the unaffected hemisphere in four patients (23.5%) in non-reconstructed group. Fractional anisotropy and mean diffusivity values of the affected hemisphere in reconstructed group also did not show significant differences from those in the unaffected hemisphere of reconstructed group and the control group (p > 0.05). However, the tract volume of the affected hemisphere in reconstructed group was significantly lower than that of the unaffected hemisphere in reconstructed group and the control group (p < 0.05). Conclusion: A large portion of patients with thalamic hemorrhage appeared to suffer severe injury of the ipsilesional MTT (77.3%) and 18.2% of them appeared to suffer severe injury even in the contralesional MTT. In addition, the remaining 22.7% of patients who had preserved integrity of the ipsilesional MTT appeared to suffer partial injury of the ipsilesional MTT.
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Affiliation(s)
- Hyeok Gyu Kwon
- Department of Physical Medicine and Rehabilitation, College of Medicine, Yeungnam University , Daegu , South Korea
| | - Han Do Lee
- Department of Physical Medicine and Rehabilitation, College of Medicine, Yeungnam University , Daegu , South Korea
| | - Sung Ho Jang
- Department of Physical Medicine and Rehabilitation, College of Medicine, Yeungnam University , Daegu , South Korea
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Edelstyn NMJ, Mayes AR, Denby C, Ellis SJ. Impairment in material-specific long-term memory following unilateral mediodorsal thalamic damage and presumed partial disconnection of the mammillo-thalamic tract. J Neuropsychol 2011; 6:119-40. [DOI: 10.1111/j.1748-6653.2011.02019.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Carlesimo GA, Lombardi MG, Caltagirone C. Vascular thalamic amnesia: a reappraisal. Neuropsychologia 2011; 49:777-789. [PMID: 21255590 DOI: 10.1016/j.neuropsychologia.2011.01.026] [Citation(s) in RCA: 143] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2010] [Revised: 01/07/2011] [Accepted: 01/12/2011] [Indexed: 11/25/2022]
Abstract
In humans lacunar infarcts in the mesial and anterior regions of the thalami are frequently associated with amnesic syndromes. In this review paper, we scrutinized 41 papers published between 1983 and 2009 that provided data on a total of 83 patients with the critical ischemic lesions (i.e. 17 patients with right-sided lesions, 25 with left-sided lesions and 41 with bilateral lesions). We aimed to find answers to the following questions concerning the vascular thalamic amnesia syndrome: (i) Which qualitative pattern of memory impairment (and associated cognitive and behavioral deficits) do these patients present? (ii) Which lesioned intrathalamic structures are primarily responsible for the amnesic syndrome? (iii) Are the recollection and familiarity components of declarative memory underlain by the same or by different thalamic structures? Results of the review indicate that, similar to patients with amnesic syndromes due to mesio-temporal lobe damage, patients with vascular thalamic amnesia display a prevalent deficit of declarative anterograde long-term memory, a less consistent deficit of declarative retrograde long-term memory and substantially spared short-term and implicit memory. Unlike mesio-temporal lobe patients, however, vascular thalamic amnesics often present dysexecutive and behavioral deficits similar to those observed in patients with frontal damage. The presence of an amnesic syndrome in patients with thalamic lacunar infarcts is strongly predicted by involvement of the mammillo-thalamic tract, which connects the anterior nuclei complex to the hippocampus proper via the fornix and the mammillary bodies. Finally, data reported in a few single cases provide support for the hypothesis that thalamic regions connected to distinct areas of the mesio-temporal lobe play differential roles in recollection and familiarity processes. The mammillo-thalamic tract/anterior nuclei axis seems primarily implicated in recollective processes, whereas the ventroamygdalofugal pathway/medio-dorsal axis primarily underlies familiarity processes.
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Affiliation(s)
- Giovanni Augusto Carlesimo
- Neurology Clinic, Tor Vergata University, Rome, Italy; Unit of Clinical and Behavioural Neurology, Santa Lucia Foundation, IRCCS, Rome, Italy.
| | | | - Carlo Caltagirone
- Neurology Clinic, Tor Vergata University, Rome, Italy; Unit of Clinical and Behavioural Neurology, Santa Lucia Foundation, IRCCS, Rome, Italy
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Cognitive, affective and behavioural disturbances following vascular thalamic lesions: a review. Cortex 2010; 47:273-319. [PMID: 21111408 DOI: 10.1016/j.cortex.2010.09.002] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2010] [Revised: 06/21/2010] [Accepted: 09/15/2010] [Indexed: 11/23/2022]
Abstract
During the last decades, many studies have shown that the thalamus is crucially involved in language and cognition. We critically reviewed a study corpus of 465 patients with vascular thalamic lesions published in the literature since 1980. 42 out of 465 (9%) cases with isolated thalamic lesions allowed further neurocognitive analysis. On the neurolinguistic level, fluent output (=31/33; 93.9%), normal to mild impairment of repetition (=33/35; 94.3%), mild dysarthria (=8/9; 88.9%) and normal to mild impairment of auditory comprehension (=27/34; 79.4%) were most commonly found in the group of patients with left and bilateral thalamic lesions. The taxonomic label of thalamic aphasia applied to the majority of the patients with left thalamic damage (=7/11; 63.6%) and to one patient with bithalamic lesions (=1/1). On the neuropsychological level, almost 90% of the left thalamic and bithalamic patient group presented with amnestic problems, executive dysfunctions and behaviour and/or mood alterations. In addition, two thirds (2/3) of the patients with bilateral thalamic damage presented with a typical cluster of neurocognitive disturbances consisting of constructional apraxia, anosognosia, desorientation, global intellectual dysfunctioning, amnesia, and executive dysfunctions associated with behaviour and/or mood alterations. Our study supports the long-standing view of a 'lateralised linguistic thalamus' but restates the issue of a 'lateralised cognitive thalamus'. In addition, critical analysis of the available literature supports the view that aphasia following left or bithalamic damage constitutes a prototypical linguistic syndrome.
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Mammillothalamic tract in human brain: Diffusion tensor tractography study. Neurosci Lett 2010; 481:51-3. [DOI: 10.1016/j.neulet.2010.06.052] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2010] [Revised: 06/17/2010] [Accepted: 06/21/2010] [Indexed: 11/20/2022]
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Collinson SL, Meyyappan A, Rosenfeld JV. Injury and recovery: Severe amnestic syndrome following traumatic brain injury. Brain Inj 2009; 23:71-6. [DOI: 10.1080/02699050802649647] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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12
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Cipolotti L, Husain M, Crinion J, Bird CM, Khan SS, Losseff N, Howard RS, Leff AP. The role of the thalamus in amnesia: a tractography, high-resolution MRI and neuropsychological study. Neuropsychologia 2008; 46:2745-58. [PMID: 18597798 DOI: 10.1016/j.neuropsychologia.2008.05.009] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2007] [Revised: 05/06/2008] [Accepted: 05/11/2008] [Indexed: 11/18/2022]
Abstract
Although it is well established that thalamic lesions may lead to profound amnesia, the precise contribution of thalamic sub-regions to memory remains unclear. In an influential article Aggleton and Brown proposed that recognition memory depends on two processes supported by distinct thalamic and cortical structures. Familiarity is mediated by the mediodorsal (MD) thalamic nucleus and the entorhinal/perirhinal cortex. Recollection is mediated by the anterior thalamic nucleus (AN), the mamillothalamic tract (MTT) and the hippocampus. The authors also suggested that the lateral dorsal nucleus (LD) may contribute to the thalamic/hippocampus system, thereby implying that the LD may play a role in recollection. Given the finding that material specific amnesia can occur following thalamic lesions, we tested an extension of the Aggleton and Brown model. We predicted that patients with bilateral lesions with a bias to the left or right MD or AN/MTT/LD may exhibit impaired familiarity or recollection on verbal or non-verbal memoranda. We report two patients with highly focal thalamic lesions and profound memory impairments affecting verbal and non-verbal memoranda. For the first time, diffusion-weighted imaging was employed to perform tractography of the MTT along with high-resolution anatomical MRI and detailed assessments of verbal and non-verbal memory. Our data support only some aspects of the Aggleton and Brown model. Both patients had left MD nucleus and AN/MTT lesions and performed poorly on familiarity and recall for verbal memoranda, just as predicted by the model. However, both patients' performance for non-verbal memoranda (human faces and topography) is more difficult to reconcile with the model. Patient 1 had damage to the right AN/MTT/LD with sparing of the MD: familiarity should therefore have been preserved but was not. Patient 2 had damage to the right MD with sparing of AN/MTT: recollection should have been preserved but was not. This finding raises the possibility that fractionation of familiarity and recollection to separate thalamic nuclei may not fully capture the role of thalamic sub-regions in memory function.
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Affiliation(s)
- L Cipolotti
- Department of Neuropsychology, National Hospital for Neurology and Neurosurgery, Queen Square, London, United Kingdom.
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Abstract
BACKGROUND The authors investigated type and severity of cognitive decline in older adults immediately and 3 months after noncardiac surgery. Changes in instrumental activities of daily living were examined relative to type of cognitive decline. METHODS Of the initial 417 older adults enrolled in the study, 337 surgery patients and 60 controls completed baseline, discharge, and/or 3-month postoperative cognitive and instrumental activities of daily living measures. Reliable change methods were used to examine three types of cognitive decline: memory, executive function, and combined executive function/memory. SD cutoffs were used to grade severity of change as mild, moderate or severe. RESULTS At discharge, 186 (56%) patients experienced cognitive decline, with an equal distribution in type and severity. At 3 months after surgery, 231 patients (75.1%) experienced no cognitive decline, 42 (13.6%) showed only memory decline, 26 (8.4%) showed only executive function decline, and 9 (2.9%) showed decline in both executive and memory domains. Of those with cognitive decline, 36 (46.8%) had mild, 25 (32.5%) had moderate, and 16 (20.8%) had severe decline. The combined group had more severe impairment. Executive function or combined (memory and executive) deficits involved greater levels of functional (i.e., instrumental activities of daily living) impairment. The combined group was less educated than the unimpaired and memory groups. CONCLUSION Postsurgical cognitive presentation varies with time of testing. At 3 months after surgery, more older adults experienced memory decline, but only those with executive or combined cognitive decline had functional limitations. The findings have relevance for patients and caregivers. Future research should examine how perioperative factors influence neuronal systems.
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Abstract
It is controversial whether isolated lesions of mammillothalamic tract (MTT) produce significant amnesia. Since the MTT is small and adjacent to several important structures for memory, amnesia associated with isolated MTT infarction has been rarely reported. We report a patient who developed amnesia following an infarction of the left MTT that spared adjacent memory-related structures including the anterior thalamic nucleus. The patient s memory deficit was characterized by a severe anterograde encoding deficit and retrograde amnesia with a temporal gradient. In contrast, he did not show either frontal executive dysfunction or personality change that is frequently recognized in the anterior or medial thalamic lesion. We postulate that an amnesic syndrome can develop following discrete lesions of the MTT.
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Affiliation(s)
- Key-Chung Park
- Department of Neurology, Kyung Hee University School of Medicine, Seoul, Korea
| | - Sung-Sang Yoon
- Department of Neurology, Kyung Hee University School of Medicine, Seoul, Korea
| | - Dae-il Chang
- Department of Neurology, Kyung Hee University School of Medicine, Seoul, Korea
| | - Kyung-Cheon Chung
- Department of Neurology, Kyung Hee University School of Medicine, Seoul, Korea
| | - Tae-Beom Ahn
- Department of Neurology, Kyung Hee University School of Medicine, Seoul, Korea
| | - Bon D. Ku
- Department of Neurology, Kwandong University College of Medicine, Myongji Hospital, Goyang, Korea
| | - John C. Adair
- Department of Neurology, University of New Mexico and Veterans Affairs Medical Center, Albuquerque, New Mexico, U.S.A
| | - Duk L. Na
- Department of Neurology, Sungkyunkwan University School of Medicine, Samsung Medical Center, Seoul, Korea
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Cheesman AL, Barker RA, Lewis SJG, Robbins TW, Owen AM, Brooks DJ. Lateralisation of striatal function: evidence from 18F-dopa PET in Parkinson's disease. J Neurol Neurosurg Psychiatry 2005; 76:1204-10. [PMID: 16107352 PMCID: PMC1739780 DOI: 10.1136/jnnp.2004.055079] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
OBJECTIVES The aetiology of the cognitive changes seen in Parkinson's disease (PD) is multifactorial but it is likely that a significant contribution arises from the disruption of dopaminergic pathways. This study aimed to investigate the contribution of the dopaminergic system to performance on two executive tasks using (18)F-6-fluorodopa positron emission tomography ((18)F-dopa PET) in PD subjects with early cognitive changes. METHODS 16 non-demented, non-depressed PD subjects were evaluated with the Tower of London (TOL) spatial planning task, a verbal working memory task (VWMT) and (18)F-dopa PET, all known to be affected in early PD. Statistical parametric mapping (SPM) localised brain regions in which (18)F-dopa uptake covaried with performance scores. Frontal cortical resting glucose metabolism was assessed with (18)F-fluoro-2-deoxy-D-glucose ((18)F-FDG) PET. RESULTS SPM localised significant covariation between right caudate (18)F-dopa uptake (Ki) and TOL scores and between left anterior putamen Ki and VWMT performance. No significant covariation was found between task scores and (18)F-dopa Ki values in either limbic or cortical regions. Frontal cortical glucose metabolism was preserved in all cases. CONCLUSIONS These findings support a causative role of striatal dopaminergic depletion in the early impairment of executive functions seen in PD. They suggest that spatial and verbal executive tasks require integrity of the right and left striatum, respectively, and imply that the pattern of cognitive changes manifest by a patient with PD may reflect differential dopamine loss in the two striatal complexes.
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Affiliation(s)
- A L Cheesman
- Medical Research Council Clinical Sciences Centre, Imperial College, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK.
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Abstract
Young onset dementia is a challenging clinical problem with potentially devastating medical and social consequences. The differential diagnosis is wide, and includes a number of rare sporadic and hereditary diseases. However, accurate diagnosis is often possible, and all patients should be thoroughly investigated to identify treatable processes. This review presents an approach to the diagnosis, investigation, and management of patients with young onset dementia, with particular reference to common and treatable causes.
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Affiliation(s)
- E L Sampson
- Dementia Research Group, Institute of Neurology, University College London, London, UK
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Abstract
BACKGROUND AND PURPOSE The criteria of the National Institute of Neurological Disorders and Stroke (NINDS)-Association Internationale pour la Recherche et l'Enseignement en Neurosciences (AIREN) include thalamic lesions for the diagnosis of vascular dementia (VaD). Although studies concerning VaD and brain aging advocate the use of fluid-attenuated inversion recovery (FLAIR) or T2-weighted images (T2-WI) to detect ischemic lesions, none compared the sensitivity of these sequences to depict thalamic lesions. METHODS We performed a blinded review of T2-WI and FLAIR images in 73 patients fulfilling the radiological part of the NINDS-AIREN criteria (mean age, 71 years; range, 49 to 83 years). This sample was drawn from a large multicenter trial on VaD and was expected to have a high prevalence of thalamic lesions. In a side-by-side review, including T1-weighted images as well, lesions were classified according to presumed underlying pathology. RESULTS The total number of thalamic lesions was 214. Two hundred eight (97%) were detected on T2-WI, but only 117 (55%) were detected on FLAIR (chi(2)=5.1; P<0.05). Although the mean size of lesions detected on T2-WI and not on FLAIR (4.4 mm) was significantly lower than the mean size of lesions detected on both sequences (6.7 mm) (P<0.001), 5 of the 29 lesions >10 mm on T2-WI were not visible on FLAIR. FLAIR detected only 81 (51%) of the 158 probable ischemic lesions and 30 (60%) of the 50 probable microbleeds. CONCLUSIONS FLAIR should not be used as the only T2-weighted sequence to detect thalamic lesions in patients suspected of having VaD.
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