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Brima T, Beker S, Prinsloo KD, Butler JS, Djukic A, Freedman EG, Molholm S, Foxe JJ. Probing a neural unreliability account of auditory sensory processing atypicalities in Rett Syndrome. J Neurodev Disord 2024; 16:28. [PMID: 38831410 DOI: 10.1186/s11689-024-09544-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Accepted: 05/21/2024] [Indexed: 06/05/2024] Open
Abstract
BACKGROUND In the search for objective tools to quantify neural function in Rett Syndrome (RTT), which are crucial in the evaluation of therapeutic efficacy in clinical trials, recordings of sensory-perceptual functioning using event-related potential (ERP) approaches have emerged as potentially powerful tools. Considerable work points to highly anomalous auditory evoked potentials (AEPs) in RTT. However, an assumption of the typical signal-averaging method used to derive these measures is "stationarity" of the underlying responses - i.e. neural responses to each input are highly stereotyped. An alternate possibility is that responses to repeated stimuli are highly variable in RTT. If so, this will significantly impact the validity of assumptions about underlying neural dysfunction, and likely lead to overestimation of underlying neuropathology. To assess this possibility, analyses at the single-trial level assessing signal-to-noise ratios (SNR), inter-trial variability (ITV) and inter-trial phase coherence (ITPC) are necessary. METHODS AEPs were recorded to simple 100 Hz tones from 18 RTT and 27 age-matched controls (Ages: 6-22 years). We applied standard AEP averaging, as well as measures of neuronal reliability at the single-trial level (i.e. SNR, ITV, ITPC). To separate signal-carrying components from non-neural noise sources, we also applied a denoising source separation (DSS) algorithm and then repeated the reliability measures. RESULTS Substantially increased ITV, lower SNRs, and reduced ITPC were observed in auditory responses of RTT participants, supporting a "neural unreliability" account. Application of the DSS technique made it clear that non-neural noise sources contribute to overestimation of the extent of processing deficits in RTT. Post-DSS, ITV measures were substantially reduced, so much so that pre-DSS ITV differences between RTT and TD populations were no longer detected. In the case of SNR and ITPC, DSS substantially improved these estimates in the RTT population, but robust differences between RTT and TD were still fully evident. CONCLUSIONS To accurately represent the degree of neural dysfunction in RTT using the ERP technique, a consideration of response reliability at the single-trial level is highly advised. Non-neural sources of noise lead to overestimation of the degree of pathological processing in RTT, and denoising source separation techniques during signal processing substantially ameliorate this issue.
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Affiliation(s)
- Tufikameni Brima
- The Frederick J. and Marion A. Schindler Cognitive Neurophysiology Laboratory, Ernest J. Del Monte Institute for Neuroscience & Department of Neuroscience, University of Rochester School of Medicine and Dentistry, Rochester, New York, USA
| | - Shlomit Beker
- The Cognitive Neurophysiology Laboratory, Departments of Pediatrics and Neuroscience, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, USA
| | - Kevin D Prinsloo
- The Frederick J. and Marion A. Schindler Cognitive Neurophysiology Laboratory, Ernest J. Del Monte Institute for Neuroscience & Department of Neuroscience, University of Rochester School of Medicine and Dentistry, Rochester, New York, USA
| | - John S Butler
- School of Mathematical Sciences, Technological University Dublin, Kevin Street Campus, Dublin 8, Ireland
| | - Aleksandra Djukic
- Rett Syndrome Center, Department of Neurology, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, USA
| | - Edward G Freedman
- The Frederick J. and Marion A. Schindler Cognitive Neurophysiology Laboratory, Ernest J. Del Monte Institute for Neuroscience & Department of Neuroscience, University of Rochester School of Medicine and Dentistry, Rochester, New York, USA
| | - Sophie Molholm
- The Frederick J. and Marion A. Schindler Cognitive Neurophysiology Laboratory, Ernest J. Del Monte Institute for Neuroscience & Department of Neuroscience, University of Rochester School of Medicine and Dentistry, Rochester, New York, USA
- The Cognitive Neurophysiology Laboratory, Departments of Pediatrics and Neuroscience, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, USA
| | - John J Foxe
- The Frederick J. and Marion A. Schindler Cognitive Neurophysiology Laboratory, Ernest J. Del Monte Institute for Neuroscience & Department of Neuroscience, University of Rochester School of Medicine and Dentistry, Rochester, New York, USA.
- The Cognitive Neurophysiology Laboratory, Departments of Pediatrics and Neuroscience, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, USA.
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Brima T, Beker S, Prinsloo KD, Butler JS, Djukic A, Freedman EG, Molholm S, Foxe JJ. Probing a neural unreliability account of auditory sensory processing atypicalities in Rett Syndrome. RESEARCH SQUARE 2024:rs.3.rs-3863341. [PMID: 38352397 PMCID: PMC10862956 DOI: 10.21203/rs.3.rs-3863341/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/22/2024]
Abstract
Background In the search for objective tools to quantify neural function in Rett Syndrome (RTT), which are crucial in the evaluation of therapeutic efficacy in clinical trials, recordings of sensory-perceptual functioning using event-related potential (ERP) approaches have emerged as potentially powerful tools. Considerable work points to highly anomalous auditory evoked potentials (AEPs) in RTT. However, an assumption of the typical signal-averaging method used to derive these measures is "stationarity" of the underlying responses - i.e. neural responses to each input are highly stereotyped. An alternate possibility is that responses to repeated stimuli are highly variable in RTT. If so, this will significantly impact the validity of assumptions about underlying neural dysfunction, and likely lead to overestimation of underlying neuropathology. To assess this possibility, analyses at the single-trial level assessing signal-to-noise ratios (SNR), inter-trial variability (ITV) and inter-trial phase coherence (ITPC) are necessary. Methods AEPs were recorded to simple 100Hz tones from 18 RTT and 27 age-matched controls (Ages: 6-22 years). We applied standard AEP averaging, as well as measures of neuronal reliability at the single-trial level (i.e. SNR, ITV, ITPC). To separate signal-carrying components from non-neural noise sources, we also applied a denoising source separation (DSS) algorithm and then repeated the reliability measures. Results Substantially increased ITV, lower SNRs, and reduced ITPC were observed in auditory responses of RTT participants, supporting a "neural unreliability" account. Application of the DSS technique made it clear that non-neural noise sources contribute to overestimation of the extent of processing deficits in RTT. Post-DSS, ITV measures were substantially reduced, so much so that pre-DSS ITV differences between RTT and TD populations were no longer detected. In the case of SNR and ITPC, DSS substantially improved these estimates in the RTT population, but robust differences between RTT and TD were still fully evident. Conclusions To accurately represent the degree of neural dysfunction in RTT using the ERP technique, a consideration of response reliability at the single-trial level is highly advised. Non-neural sources of noise lead to overestimation of the degree of pathological processing in RTT, and denoising source separation techniques during signal processing substantially ameliorate this issue.
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Brima T, Beker S, Prinsloo KD, Butler JS, Djukic A, Freedman EG, Molholm S, Foxe JJ. Probing a neural unreliability account of auditory sensory processing atypicalities in Rett Syndrome. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.01.25.24301723. [PMID: 38343802 PMCID: PMC10854351 DOI: 10.1101/2024.01.25.24301723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/26/2024]
Abstract
Background In the search for objective tools to quantify neural function in Rett Syndrome (RTT), which are crucial in the evaluation of therapeutic efficacy in clinical trials, recordings of sensory-perceptual functioning using event-related potential (ERP) approaches have emerged as potentially powerful tools. Considerable work points to highly anomalous auditory evoked potentials (AEPs) in RTT. However, an assumption of the typical signal-averaging method used to derive these measures is "stationarity" of the underlying responses - i.e. neural responses to each input are highly stereotyped. An alternate possibility is that responses to repeated stimuli are highly variable in RTT. If so, this will significantly impact the validity of assumptions about underlying neural dysfunction, and likely lead to overestimation of underlying neuropathology. To assess this possibility, analyses at the single-trial level assessing signal-to-noise ratios (SNR), inter-trial variability (ITV) and inter-trial phase coherence (ITPC) are necessary. Methods AEPs were recorded to simple 100Hz tones from 18 RTT and 27 age-matched controls (Ages: 6-22 years). We applied standard AEP averaging, as well as measures of neuronal reliability at the single-trial level (i.e. SNR, ITV, ITPC). To separate signal-carrying components from non-neural noise sources, we also applied a denoising source separation (DSS) algorithm and then repeated the reliability measures. Results Substantially increased ITV, lower SNRs, and reduced ITPC were observed in auditory responses of RTT participants, supporting a "neural unreliability" account. Application of the DSS technique made it clear that non-neural noise sources contribute to overestimation of the extent of processing deficits in RTT. Post-DSS, ITV measures were substantially reduced, so much so that pre-DSS ITV differences between RTT and TD populations were no longer detected. In the case of SNR and ITPC, DSS substantially improved these estimates in the RTT population, but robust differences between RTT and TD were still fully evident. Conclusions To accurately represent the degree of neural dysfunction in RTT using the ERP technique, a consideration of response reliability at the single-trial level is highly advised. Non-neural sources of noise lead to overestimation of the degree of pathological processing in RTT, and denoising source separation techniques during signal processing substantially ameliorate this issue.
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Affiliation(s)
- Tufikameni Brima
- The Frederick J. and Marion A. Schindler Cognitive Neurophysiology Laboratory Ernest J. Del Monte Institute for Neuroscience &Department of Neuroscience University of Rochester School of Medicine and Dentistry Rochester, New York 14642, USA
| | - Shlomit Beker
- The Cognitive Neurophysiology Laboratory Departments of Pediatrics and Neuroscience Albert Einstein College of Medicine & Montefiore Medical Center Bronx, New York 10461, USA
| | - Kevin D. Prinsloo
- The Frederick J. and Marion A. Schindler Cognitive Neurophysiology Laboratory Ernest J. Del Monte Institute for Neuroscience &Department of Neuroscience University of Rochester School of Medicine and Dentistry Rochester, New York 14642, USA
| | - John S. Butler
- School of Mathematical Sciences Technological University Dublin Kevin Street Campus, Dublin 8, Ireland
| | - Aleksandra Djukic
- Rett Syndrome Center Department of Neurology Albert Einstein College of Medicine & Montefiore Medical Center Bronx, New York 10467, USA
| | - Edward G. Freedman
- The Frederick J. and Marion A. Schindler Cognitive Neurophysiology Laboratory Ernest J. Del Monte Institute for Neuroscience &Department of Neuroscience University of Rochester School of Medicine and Dentistry Rochester, New York 14642, USA
| | - Sophie Molholm
- The Frederick J. and Marion A. Schindler Cognitive Neurophysiology Laboratory Ernest J. Del Monte Institute for Neuroscience &Department of Neuroscience University of Rochester School of Medicine and Dentistry Rochester, New York 14642, USA
- The Cognitive Neurophysiology Laboratory Departments of Pediatrics and Neuroscience Albert Einstein College of Medicine & Montefiore Medical Center Bronx, New York 10461, USA
| | - John J. Foxe
- The Frederick J. and Marion A. Schindler Cognitive Neurophysiology Laboratory Ernest J. Del Monte Institute for Neuroscience &Department of Neuroscience University of Rochester School of Medicine and Dentistry Rochester, New York 14642, USA
- The Cognitive Neurophysiology Laboratory Departments of Pediatrics and Neuroscience Albert Einstein College of Medicine & Montefiore Medical Center Bronx, New York 10461, USA
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Kostanian D, Rebreikina A, Voinova V, Sysoeva O. Effect of presentation rate on auditory processing in Rett syndrome: event-related potential study. Mol Autism 2023; 14:40. [PMID: 37885019 PMCID: PMC10605980 DOI: 10.1186/s13229-023-00566-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 09/05/2023] [Indexed: 10/28/2023] Open
Abstract
BACKGROUND Rett syndrome (RS) is a rare neurodevelopmental disorder characterized by mutations in the MECP2 gene. Patients with RS have severe motor abnormalities and are often unable to walk, use hands and speak. The preservation of perceptual and cognitive functions is hard to assess, while clinicians and care-givers point out that these patients need more time to process information than typically developing peers. Neurophysiological correlates of auditory processing have been also found to be distorted in RS, but sound presentation rates were relatively quick in these studies (stimulus onset asynchrony, SOA < 1000 ms). As auditory event-related potential (ERP) is typically increased with prolongation of SOA we aim to study if SOA prolongation might compensate for observed abnormalities. METHODS We presented a repetitive stimulus (1000 Hz) at three different SOAs of 900 ms, 1800 ms, and 3600 ms in children with RS (N = 24, Mean age = 9.0 ± 3.1) and their typical development (TD) peers (N = 27, Mean age = 9.7 ± 3.4) while recording 28-channels electroencephalogram, EEG. Some RS participants (n = 10) did not show clear ERP and were excluded from the analysis. RESULTS Major ERP components (here assessed as N1P1 and P2N1 peak-to-peak values) were smaller at SOA 900 than at longer SOAs in both groups, pointing out that the basic mechanism of adaptation in the auditory system is preserved in at least in RS patients with evident ERPs. At the same time the latencies of these components were significantly delayed in the RS than in TD. Moreover, late components (P2N1 and N2P2) were drastically reduced in Rett syndrome irrespective of the SOA, suggesting a largely affected mechanism of integration of upcoming sensory input with memory. Moreover, developmental stagnation of auditory ERP characterized patients with RS: absence of typical P2N1 enlargement and P1 and N1 shortening with age at least for shortest SOA. LIMITATIONS We could not figure out the cause for the high percentage of no-evident ERP RS participants and our final sample of the RS group was rather small. Also, our study did not include a control clinical group. CONCLUSIONS Thus, auditory ERPs inform us about abnormalities within auditory processing that cannot be fully overcomed by slowing presentation rate.
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Affiliation(s)
- Daria Kostanian
- Center for Cognitive Sciences, Sirius University of Science and Technology, Olympic Ave 1, Sochi, Russia, 354340.
| | - Anna Rebreikina
- Center for Cognitive Sciences, Sirius University of Science and Technology, Olympic Ave 1, Sochi, Russia, 354340
- Laboratory of Human Higher Nervous Activity, Institute of Higher Nervous Activity and Neurophysiology of RAS, Moscow, Russia, 117485
| | - Victoria Voinova
- Veltischev Research and Clinical Institute for Pediatrics of the Pirogov, Russian National Research Medical University, Ministry of Health of Russian Federation, Moscow, Russia, 125412
| | - Olga Sysoeva
- Center for Cognitive Sciences, Sirius University of Science and Technology, Olympic Ave 1, Sochi, Russia, 354340
- Laboratory of Human Higher Nervous Activity, Institute of Higher Nervous Activity and Neurophysiology of RAS, Moscow, Russia, 117485
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Shaheen G, Fleischman D. A case of JOAG in a patient with Rett syndrome. Am J Ophthalmol Case Rep 2023; 29:101762. [DOI: 10.1016/j.ajoc.2022.101762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 11/16/2022] [Accepted: 11/26/2022] [Indexed: 12/05/2022] Open
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Electrophysiological and Behavioral Evidence for Hyper- and Hyposensitivity in Rare Genetic Syndromes Associated with Autism. Genes (Basel) 2022; 13:genes13040671. [PMID: 35456477 PMCID: PMC9027402 DOI: 10.3390/genes13040671] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 03/29/2022] [Accepted: 04/05/2022] [Indexed: 01/27/2023] Open
Abstract
Our study reviewed abnormalities in spontaneous, as well as event-related, brain activity in syndromes with a known genetic underpinning that are associated with autistic symptomatology. Based on behavioral and neurophysiological evidence, we tentatively subdivided the syndromes on primarily hyper-sensitive (Fragile X, Angelman) and hypo-sensitive (Phelan–McDermid, Rett, Tuberous Sclerosis, Neurofibromatosis 1), pointing to the way of segregation of heterogeneous idiopathic ASD, that includes both hyper-sensitive and hypo-sensitive individuals. This segmentation links abnormalities in different genes, such as FMR1, UBE3A, GABRB3, GABRA5, GABRG3, SHANK3, MECP2, TSC1, TSC2, and NF1, that are causative to the above-mentioned syndromes and associated with synaptic transmission and cell growth, as well as with translational and transcriptional regulation and with sensory sensitivity. Excitation/inhibition imbalance related to GABAergic signaling, and the interplay of tonic and phasic inhibition in different brain regions might underlie this relationship. However, more research is needed. As most genetic syndromes are very rare, future investigations in this field will benefit from multi-site collaboration with a common protocol for electrophysiological and event-related potential (EEG/ERP) research that should include an investigation into all modalities and stages of sensory processing, as well as potential biomarkers of GABAergic signaling (such as 40-Hz ASSR).
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Armstrong C, Marsh ED. Electrophysiological Biomarkers in Genetic Epilepsies. Neurotherapeutics 2021; 18:1458-1467. [PMID: 34642905 PMCID: PMC8609056 DOI: 10.1007/s13311-021-01132-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/27/2021] [Indexed: 02/04/2023] Open
Abstract
Precision treatments for epilepsy targeting the underlying genetic diagnoses are becoming a reality. Historically, the goal of epilepsy treatments was to reduce seizure frequency. In the era of precision medicine, however, outcomes such as prevention of epilepsy progression or even improvements in cognitive functions are both aspirational targets for any intervention. Developing methods, both in clinical trial design and in novel endpoints, will be necessary for measuring, not only seizures, but also the other neurodevelopmental outcomes that are predicted to be targeted by precision treatments. Biomarkers that quantitatively measure disease progression or network level changes are needed to allow for unbiased measurements of the effects of any gene-level treatments. Here, we discuss some of the promising electrophysiological biomarkers that may be of use in clinical trials of precision therapies, as well as the difficulties in implementing them.
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Affiliation(s)
- Caren Armstrong
- Division of Neurology and Pediatric Epilepsy Program, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Eric D Marsh
- Division of Neurology and Pediatric Epilepsy Program, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA.
- Department of Pediatrics and Neurology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104, USA.
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Saby JN, Benke TA, Peters SU, Standridge SM, Matsuzaki J, Cutri-French C, Swanson LC, Lieberman DN, Key AP, Percy AK, Neul JL, Nelson CA, Roberts TP, Marsh ED. Multisite Study of Evoked Potentials in Rett Syndrome. Ann Neurol 2021; 89:790-802. [PMID: 33480039 PMCID: PMC8882338 DOI: 10.1002/ana.26029] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 01/18/2021] [Accepted: 01/19/2021] [Indexed: 01/04/2023]
Abstract
OBJECTIVE The aim of the current study was to evaluate the utility of evoked potentials as a biomarker of cortical function in Rett syndrome (RTT). As a number of disease-modifying therapeutics are currently under development, there is a pressing need for biomarkers to objectively and precisely assess the effectiveness of these treatments. METHOD Yearly visual evoked potentials (VEPs) and auditory evoked potentials (AEPs) were acquired from individuals with RTT, aged 2 to 37 years, and control participants across 5 sites as part of the Rett Syndrome and Related Disorders Natural History Study. Baseline and year 1 data, when available, were analyzed and the repeatability of the results was tested. Two syndrome-specific measures from the Natural History Study were used for evaluating the clinical relevance of the VEP and AEP parameters. RESULTS At the baseline study, group level comparisons revealed reduced VEP and AEP amplitude in RTT compared to control participants. Further analyses within the RTT group indicated that this reduction was associated with RTT-related symptoms, with greater severity associated with lower VEP and AEP amplitude. In participants with RTT, VEP and AEP amplitude was also negatively associated with age. Year 1 follow-up data analyses yielded similar findings and evidence of repeatability of EPs at the individual level. INTERPRETATION The present findings indicate the promise of evoked potentials (EPs) as an objective measure of disease severity in individuals with RTT. Our multisite approach demonstrates potential research and clinical applications to provide unbiased assessment of disease staging, prognosis, and response to therapy. ANN NEUROL 2021;89:790-802.
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Affiliation(s)
- Joni N. Saby
- Division of Radiology Research, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Timothy A. Benke
- Department of Pediatrics, Neurology, Pharmacology and Otolaryngology, University of Colorado School of Medicine and Children’s Hospital Colorado, Aurora, Colorado
| | - Sarika U. Peters
- Department of Pediatrics, Vanderbilt University Medical Center, Vanderbilt Kennedy Center, Nashville, Tennessee
| | - Shannon M. Standridge
- Cincinnati Children’s Hospital Medical Center, Division of Neurology and University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - Junko Matsuzaki
- Division of Radiology Research, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Clare Cutri-French
- Division of Child Neurology, Children’s Hospital of Philadelphia, Departments of Neurology and Pediatrics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
| | - Lindsay C. Swanson
- Department of Neurology, Boston Children’s Hospital, Boston, Massachusetts
| | - David N. Lieberman
- Department of Neurology, Boston Children’s Hospital, Boston, Massachusetts
| | - Alexandra P. Key
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Vanderbilt Kennedy Center, Nashville, Tennessee
| | - Alan K. Percy
- Department of Pediatrics, University of Alabama at Birmingham, Birmingham, Alabama
| | - Jeffrey L. Neul
- Department of Pediatrics, Vanderbilt University Medical Center, Vanderbilt Kennedy Center, Nashville, Tennessee
| | - Charles A. Nelson
- Laboratories of Cognitive Neuroscience, Boston Children’s Hospital, Boston, Massachusetts; Department of Pediatrics, Harvard Medical School
| | - Timothy P.L. Roberts
- Division of Radiology Research, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Eric D. Marsh
- Division of Child Neurology, Children’s Hospital of Philadelphia, Departments of Neurology and Pediatrics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
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Yang D, Robertson HL, Condliffe EG, Carter MT, Dewan T, Gnanakumar V. Rehabilitation therapies in Rett syndrome across the lifespan: A scoping review of human and animal studies. J Pediatr Rehabil Med 2021; 14:69-96. [PMID: 32894256 DOI: 10.3233/prm-200683] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
PURPOSE To perform a scoping review of the evidence for therapeutic interventions to manage functional impairments associated with Rett syndrome (RTT) throughout the lifespan. METHODS MEDLINE, EMBASE, PsycINFO, CENTRAL, CINAHL, Scopus and Index to Chiropractic Literature were searched systematically up to December 2019. Two investigators independently reviewed all search results and extracted those that met the inclusion criteria. Human and animal model studies pertaining to therapies that increase functional ability or treat RTT-associated symptoms in all age groups were included. Relevant studies were grouped into intervention categories and rated using the Oxford Centre of Evidence Based Medicine Levels of Evidence. Demographics of participants, interventions, and outcomes were summarized. RESULTS Ninety-one articles representing 88 studies met the inclusion criteria, of which 80 were human clinical studies and eight were studies using animal models. Study designs were primarily case series and only six studies involved participants above the age of 40. CONCLUSION A small number of rigorously studied rehabilitation interventions have been published. Published studies aim to address a wide variety of functional impairments. Research regarding implementation of therapies for older patients with RTT is lacking and requires further exploration.
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Affiliation(s)
- David Yang
- University of Calgary Cumming School of Medicine, Calgary, AB, Canada
| | - Helen Lee Robertson
- Liaison Librarian, Clinical Medicine, Health Sciences Library, University of Calgary, Calgary, AB, Canada
| | - Elizabeth G Condliffe
- Departments of Clinical Neurosciences and Pediatrics, University of Calgary Cumming School of Medicine, Calgary, AB, Canada
| | - Melissa T Carter
- Department of Pediatrics, University of Ottawa, Ottawa, ON, Canada
| | - Tammie Dewan
- Department of Pediatrics, University of Calgary Cumming School of Medicine, Calgary, AB, Canada
| | - Vithya Gnanakumar
- Departments of Clinical Neurosciences and Pediatrics, University of Calgary Cumming School of Medicine, Calgary, AB, Canada
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Hamilton R, Bach M, Heinrich SP, Hoffmann MB, Odom JV, McCulloch DL, Thompson DA. VEP estimation of visual acuity: a systematic review. Doc Ophthalmol 2020; 142:25-74. [PMID: 32488810 PMCID: PMC7907051 DOI: 10.1007/s10633-020-09770-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Accepted: 05/05/2020] [Indexed: 01/23/2023]
Abstract
Purpose Visual evoked potentials (VEPs) can be used to measure visual resolution via a spatial frequency (SF) limit as an objective estimate of visual acuity. The aim of this systematic review is to collate descriptions of the VEP SF limit in humans, healthy and disordered, and to assess how accurately and precisely VEP SF limits reflect visual acuity. Methods The protocol methodology followed the PRISMA statement. Multiple databases were searched using “VEP” and “acuity” and associated terms, plus hand search: titles, abstracts or full text were reviewed for eligibility. Data extracted included VEP SF limits, stimulus protocols, VEP recording and analysis techniques and correspondence with behavioural acuity for normally sighted healthy adults, typically developing infants and children, healthy adults with artificially degraded vision and patients with ophthalmic or neurological conditions. Results A total of 155 studies are included. Commonly used stimulus, recording and analysis techniques are summarised. Average healthy adult VEP SF limits vary from 15 to 40 cpd, depend on stimulus, recording and analysis techniques and are often, but not always, poorer than behavioural acuity measured either psychophysically with an identical stimulus or with a clinical acuity test. The difference between VEP SF limit and behavioural acuity is variable and strongly dependent on the VEP stimulus and choice of acuity test. VEP SF limits mature rapidly, from 1.5 to 9 cpd by the end of the first month of life to 12–20 cpd by 8–12 months, with slower improvement to 20–40 cpd by 3–5 years. VEP SF limits are much better than behavioural thresholds in the youngest, typically developing infants. This difference lessens with age and reaches equivalence between 1 and 2 years; from around 3–5 years, behavioural acuity is better than the VEP SF limit, as for adults. Healthy, artificially blurred adults had slightly better behavioural acuity than VEP SF limits across a wide range of acuities, while adults with heterogeneous ophthalmic or neurological pathologies causing reduced acuity showed a much wider and less consistent relationship. For refractive error, ocular media opacity or pathology primarily affecting the retina, VEP SF limits and behavioural acuity had a fairly consistent relationship across a wide range of acuity. This relationship was much less consistent or close for primarily macular, optic nerve or neurological conditions such as amblyopia. VEP SF limits were almost always normal in patients with non-organic visual acuity loss. Conclusions The VEP SF limit has great utility as an objective acuity estimator, especially in pre-verbal children or patients of any age with motor or learning impairments which prevent reliable measurement of behavioural acuity. Its diagnostic power depends heavily on adequate, age-stratified, reference data, age-stratified empirical calibration with behavioural acuity, and interpretation in the light of other electrophysiological and clinical findings. Future developments could encompass faster, more objective and robust techniques such as real-time, adaptive control. Registration International prospective register of systematic reviews PROSPERO (https://www.crd.york.ac.uk/PROSPERO/), registration number CRD42018085666.
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Affiliation(s)
- Ruth Hamilton
- Department of Clinical Physics and Bioengineering, Royal Hospital for Children, NHS Greater Glasgow and Clyde, Glasgow, UK. .,College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK.
| | - Michael Bach
- Eye Center, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Sven P Heinrich
- Eye Center, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Michael B Hoffmann
- Department of Ophthalmology, Otto-von-Guericke University, Magdeburg, Germany.,Center for Behavioral Brain Sciences, Magdeburg, Germany
| | - J Vernon Odom
- Departments of Ophthalmology and Neuroscience, School of Medicine, West Virginia University, Morgantown, WV, USA
| | - Daphne L McCulloch
- School of Optometry and Vision Science, University of Waterloo, Waterloo, ON, Canada
| | - Dorothy A Thompson
- The Department of Clinical and Academic Ophthalmology, Great Ormond Street Hospital for Children, London, UK.,University College London Great Ormond Street Institute of Child Health, London, UK
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Saby JN, Peters SU, Roberts TPL, Nelson CA, Marsh ED. Evoked Potentials and EEG Analysis in Rett Syndrome and Related Developmental Encephalopathies: Towards a Biomarker for Translational Research. Front Integr Neurosci 2020; 14:30. [PMID: 32547374 PMCID: PMC7271894 DOI: 10.3389/fnint.2020.00030] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2019] [Accepted: 05/04/2020] [Indexed: 12/17/2022] Open
Abstract
Rett syndrome is a debilitating neurodevelopmental disorder for which no disease-modifying treatment is available. Fortunately, advances in our understanding of the genetics and pathophysiology of Rett syndrome has led to the development of promising new therapeutics for the condition. Several of these therapeutics are currently being tested in clinical trials with others likely to progress to clinical trials in the coming years. The failure of recent clinical trials for Rett syndrome and other neurodevelopmental disorders has highlighted the need for electrophysiological or other objective biological markers of treatment response to support the success of clinical trials moving forward. The purpose of this review is to describe the existing studies of electroencephalography (EEG) and evoked potentials (EPs) in Rett syndrome and discuss the open questions that must be addressed before the field can adopt these measures as surrogate endpoints in clinical trials. In addition to summarizing the human work on Rett syndrome, we also describe relevant studies with animal models and the limited research that has been carried out on Rett-related disorders, particularly methyl-CpG binding protein 2 (MECP2) duplication syndrome, CDKL5 deficiency disorder, and FOXG1 disorder.
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Affiliation(s)
- Joni N. Saby
- Lurie Family Foundations MEG Imaging Center, Department of Radiology, The Children’s Hospital of Philadelphia, Philadelphia, PA, United States
| | - Sarika U. Peters
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Timothy P. L. Roberts
- Lurie Family Foundations MEG Imaging Center, Department of Radiology, The Children’s Hospital of Philadelphia, Philadelphia, PA, United States,Department of Radiology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, United States
| | - Charles A. Nelson
- Laboratories of Cognitive Neuroscience, Division of Developmental Medicine, Boston Children’s Hospital, Harvard Medical School, Boston, MA, United States
| | - Eric D. Marsh
- Division of Neurology and Pediatrics, Children’s Hospital of Philadelphia, Philadelphia, PA, United States,Departments of Neurology and Pediatrics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, United States,*Correspondence: Eric D. Marsh
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12
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Fagiolini M, Patrizi A, LeBlanc J, Jin LW, Maezawa I, Sinnett S, Gray SJ, Molholm S, Foxe JJ, Johnston MV, Naidu S, Blue M, Hossain A, Kadam S, Zhao X, Chang Q, Zhou Z, Zoghbi H. Intellectual and Developmental Disabilities Research Centers: A Multidisciplinary Approach to Understand the Pathogenesis of Methyl-CpG Binding Protein 2-related Disorders. Neuroscience 2020; 445:190-206. [PMID: 32360592 DOI: 10.1016/j.neuroscience.2020.04.037] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 04/20/2020] [Accepted: 04/21/2020] [Indexed: 12/20/2022]
Abstract
Disruptions in the gene encoding methyl-CpG binding protein 2 (MECP2) underlie complex neurodevelopmental disorders including Rett Syndrome (RTT), MECP2 duplication disorder, intellectual disabilities, and autism. Significant progress has been made on the molecular and cellular basis of MECP2-related disorders providing a new framework for understanding how altered epigenetic landscape can derail the formation and refinement of neuronal circuits in early postnatal life and proper neurological function. This review will summarize selected major findings from the past years and particularly highlight the integrated and multidisciplinary work done at eight NIH-funded Intellectual and Developmental Disabilities Research Centers (IDDRC) across the US. Finally, we will outline a path forward with identification of reliable biomarkers and outcome measures, longitudinal preclinical and clinical studies, reproducibility of results across centers as a synergistic effort to decode and treat the pathogenesis of the complex MeCP2 disorders.
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Affiliation(s)
- Michela Fagiolini
- Children's Hospital Intellectual and Developmental Disabilities Research Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA.
| | - Annarita Patrizi
- Children's Hospital Intellectual and Developmental Disabilities Research Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Jocelyn LeBlanc
- Children's Hospital Intellectual and Developmental Disabilities Research Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Lee-Way Jin
- UC Davis MIND Institute, University of California, Sacramento, CA, USA
| | - Izumi Maezawa
- UC Davis MIND Institute, University of California, Sacramento, CA, USA
| | - Sarah Sinnett
- UNC Intellectual and Developmental Disabilities Research Center, University of North Carolina, Gene Therapy Center and Dept. of Ophthalmology, Chapel Hill, NC, USA; Department of Pediatrics, UT Southwestern Medical Center, Dallas, TX, USA
| | - Steven J Gray
- UNC Intellectual and Developmental Disabilities Research Center, University of North Carolina, Gene Therapy Center and Dept. of Ophthalmology, Chapel Hill, NC, USA; Department of Pediatrics, UT Southwestern Medical Center, Dallas, TX, USA
| | - Sophie Molholm
- The Cognitive Neurophysiology Laboratory, Departments of Pediatrics, Neuroscience, and Psychiatry and Behavioral Sciences, Albert Einstein College of Medicine, Bronx, NY, USA
| | - John J Foxe
- The Cognitive Neurophysiology Laboratory, Ernest J. Del Monte Institute for Neuroscience, Department of Neuroscience, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
| | - Michael V Johnston
- Kennedy Krieger Institute Intellectual and Developmental Disabilities Research Center/Hugo Moser Research Institute at Kennedy Krieger and Johns Hopkins School of Medicine, USA
| | - Sakkubai Naidu
- Kennedy Krieger Institute Intellectual and Developmental Disabilities Research Center/Hugo Moser Research Institute at Kennedy Krieger and Johns Hopkins School of Medicine, USA
| | - Mary Blue
- Kennedy Krieger Institute Intellectual and Developmental Disabilities Research Center/Hugo Moser Research Institute at Kennedy Krieger and Johns Hopkins School of Medicine, USA
| | - Ahamed Hossain
- Kennedy Krieger Institute Intellectual and Developmental Disabilities Research Center/Hugo Moser Research Institute at Kennedy Krieger and Johns Hopkins School of Medicine, USA
| | - Shilpa Kadam
- Kennedy Krieger Institute Intellectual and Developmental Disabilities Research Center/Hugo Moser Research Institute at Kennedy Krieger and Johns Hopkins School of Medicine, USA
| | - Xinyu Zhao
- Waisman Center, University of Wisconsin-Madison, Madison, WI, USA
| | - Quiang Chang
- Waisman Center, University of Wisconsin-Madison, Madison, WI, USA
| | - Zhaolan Zhou
- Department of Genetic, Epigenetic Institute, University of Pennsylvania Perelman School of Medicine, Intellectual and Developmental Disabilities Research Center, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Huda Zoghbi
- Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, TX, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA; Program in Developmental Biology, Baylor College of Medicine, Houston, TX, USA; Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA; Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA; Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX, USA
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13
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Sysoeva OV, Smirnov K, Stroganova TA. Sensory evoked potentials in patients with Rett syndrome through the lens of animal studies: Systematic review. Clin Neurophysiol 2019; 131:213-224. [PMID: 31812082 DOI: 10.1016/j.clinph.2019.11.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 11/07/2019] [Accepted: 11/11/2019] [Indexed: 01/04/2023]
Abstract
OBJECTIVE Systematically review the abnormalities in event related potential (ERP) recorded in Rett Syndrome (RTT) patients and animals in search of translational biomarkers of deficits related to the particular neurophysiological processes of known genetic origin (MECP2 mutations). METHODS Pubmed, ISI Web of Knowledge and BIORXIV were searched for the relevant articles according to PRISMA standards. RESULTS ERP components are generally delayed across all sensory modalities both in RTT patients and its animal model, while findings on ERPs amplitude strongly depend on stimulus properties and presentation rate. Studies on RTT animal models uncovered the abnormalities in the excitatory and inhibitory transmission as critical mechanisms underlying the ERPs changes, but showed that even similar ERP alterations in auditory and visual domains have a diverse neural basis. A range of novel approaches has been developed in animal studies bringing along the meaningful neurophysiological interpretation of ERP measures in RTT patients. CONCLUSIONS While there is a clear evidence for sensory ERPs abnormalities in RTT, to further advance the field there is a need in a large-scale ERP studies with the functionally-relevant experimental paradigms. SIGNIFICANCE The review provides insights into domain-specific neural basis of the ERP abnormalities and promotes clinical application of the ERP measures as the non-invasive functional biomarkers of RTT pathophysiology.
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Affiliation(s)
- Olga V Sysoeva
- The Cognitive Neurophysiology Laboratory, Department of Pediatrics, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, USA; The Cognitive Neurophysiology Laboratory, Ernest J. Del Monte Institute for Neuroscience, Department of Neuroscience, University of Rochester School of Medicine and Dentistry, Rochester, New York, USA; The Laboratory of Human Higher Nervous Activity, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russia.
| | - Kirill Smirnov
- Department of Neuroontogenesis, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Science, Moscow, Russia.
| | - Tatiana A Stroganova
- Center for Neurocognitive Research (MEG-Center), Moscow State University of Psychology and Education (MSUPE), Moscow, Russia; Autism Research Laboratory, Moscow State University of Psychology and Education (MSUPE), Moscow, Russia.
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de Breet LHM, Townend GS, Curfs LMG, Kingma H, Smeets EEJ, Lucieer F, Widdershoven J, van de Berg R. Challenges in evaluating the oculomotor function in individuals with Rett syndrome using electronystagmography. Eur J Paediatr Neurol 2019; 23:262-269. [PMID: 30635145 DOI: 10.1016/j.ejpn.2018.12.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 11/21/2018] [Accepted: 12/09/2018] [Indexed: 11/29/2022]
Abstract
BACKGROUND Rett syndrome (RTT) is a neurological disorder characterized by a broad spectrum of symptoms. Communication is a major area of difficulty. Use of eye tracking technology offers a potentially effective method of communication when underpinned by intact oculomotor function. In this study, oculomotor function was assessed using electronystagmography (ENG). However, challenges were encountered when examining individuals with RTT. PURPOSE To improve oculomotor examination in individuals with RTT by evaluating the challenges encountered during ENG examination. MATERIAL AND METHODS Oculomotor function was examined in 17 girls and young women with RTT and 16 typically developing (TD) individuals using ENG. Observational analysis of both performance and results indicated that challenges in examination were mainly related to quality of attention and quality of signals. Subsequently these outcome values were explored quantitatively according to percentage looking time for attention and drift for signal quality. RESULTS A significantly reduced level of attention and suboptimal electrode signals were evident in the RTT group when compared with the TD group for all tests except torsion swing. CONCLUSION The challenges in testing confirm that regular oculomotor examination should be adjusted to meet the needs of individuals with RTT. It is hypothesized that the RTT group's higher quality of attention on the torsion swing can be explained by the more forceful vestibular rather than visual-ocular stimulus operating in this test. Suggested adaptations include reducing the number of electrodes, changing the picture stimuli and bringing them closer, performing observational assessments rather than ENG, and using virtual reality goggles.
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Affiliation(s)
| | - Gillian S Townend
- Rett Expertise Center - Governor Kremers Center, Maastricht University Medical Center, Maastricht, the Netherlands.
| | - Leopold M G Curfs
- Rett Expertise Center - Governor Kremers Center, Maastricht University Medical Center, Maastricht, the Netherlands.
| | - Herman Kingma
- Division of Balance Disorders, Department of Otorhinolaryngology and Head and Neck Surgery, Maastricht University Medical Center, Maastricht, Netherlands; Faculty of Physics, Tomsk State University, Tomsk, Russia.
| | - Eric E J Smeets
- Rett Expertise Center - Governor Kremers Center, Maastricht University Medical Center, Maastricht, the Netherlands.
| | - Floor Lucieer
- Division of Balance Disorders, Department of Otorhinolaryngology and Head and Neck Surgery, Maastricht University Medical Center, Maastricht, Netherlands.
| | - Josine Widdershoven
- Division of Balance Disorders, Department of Otorhinolaryngology and Head and Neck Surgery, Maastricht University Medical Center, Maastricht, Netherlands.
| | - Raymond van de Berg
- Rett Expertise Center - Governor Kremers Center, Maastricht University Medical Center, Maastricht, the Netherlands; Division of Balance Disorders, Department of Otorhinolaryngology and Head and Neck Surgery, Maastricht University Medical Center, Maastricht, Netherlands; Faculty of Physics, Tomsk State University, Tomsk, Russia.
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15
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Townend GS, van de Berg R, de Breet LHM, Hiemstra M, Wagter L, Smeets E, Widdershoven J, Kingma H, Curfs LMG. Oculomotor Function in Individuals With Rett Syndrome. Pediatr Neurol 2018; 88:48-58. [PMID: 30340908 DOI: 10.1016/j.pediatrneurol.2018.08.022] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 08/17/2018] [Accepted: 08/18/2018] [Indexed: 11/17/2022]
Abstract
BACKGROUND Individuals with Rett syndrome (RTT) are notoriously reliant on the use of eye gaze as a primary means of communication. Underlying an ability to communicate successfully via eye gaze is a complex matrix of requirements, with an intact oculomotor system being just one element. To date, the underlying neural and motor pathways associated with eye gaze are relatively under-researched in RTT. PURPOSE This study was undertaken to plug this gap in knowledge and to further the understanding of RTT in one specific area of development and function, namely oculomotor function. MATERIAL AND METHODS The eye movements of 18 girls and young women with RTT were assessed by electronystagmography (ENG). This tested their horizontal saccadic and smooth pursuit eye movements as well as optokinetic nystagmus and vestibulo-ocular reflex. Their results were compared with normative data collected from 16 typically developing children and teenagers. RESULTS Overall, the individuals with RTT demonstrated a range of eye movements on a par with their typically developing peers. However, there were a number of difficulties in executing the ENG testing with the RTT cohort which made quantitative analysis tricky, such as reduced motivation and attention to test materials and low-quality electrode signals. CONCLUSIONS This study suggests that individuals with RTT have an intact oculomotor system. However, modifications should be made to the ENG assessment procedure to combat problems in testing and add strength to the results. Further investigation into these testing difficulties is warranted in order to inform such modifications.
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Affiliation(s)
- Gillian S Townend
- Rett Expertise Centre Netherlands - GKC, Maastricht University Medical Center, Maastricht, The Netherlands.
| | - Raymond van de Berg
- Rett Expertise Centre Netherlands - GKC, Maastricht University Medical Center, Maastricht, The Netherlands; Division of Balance Disorders, Department of Otorhinolaryngology and Head and Neck Surgery, Maastricht University Medical Center, Maastricht, The Netherlands; Faculty of Physics, Tomsk State University, Tomsk, Russia
| | | | - Monique Hiemstra
- Faculty of Medicine, Maastricht University, Maastricht, The Netherlands
| | - Laura Wagter
- Faculty of Medicine, Maastricht University, Maastricht, The Netherlands
| | - Eric Smeets
- Rett Expertise Centre Netherlands - GKC, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Josine Widdershoven
- Division of Balance Disorders, Department of Otorhinolaryngology and Head and Neck Surgery, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Herman Kingma
- Division of Balance Disorders, Department of Otorhinolaryngology and Head and Neck Surgery, Maastricht University Medical Center, Maastricht, The Netherlands; Faculty of Physics, Tomsk State University, Tomsk, Russia
| | - Leopold M G Curfs
- Rett Expertise Centre Netherlands - GKC, Maastricht University Medical Center, Maastricht, The Netherlands
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16
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Liang C, Kerr A, Qiu Y, Cristofoli F, Van Esch H, Fox MA, Mukherjee K. Optic Nerve Hypoplasia Is a Pervasive Subcortical Pathology of Visual System in Neonates. Invest Ophthalmol Vis Sci 2017; 58:5485-5496. [PMID: 29067402 PMCID: PMC5656421 DOI: 10.1167/iovs.17-22399] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Purpose Optic nerve hypoplasia (ONH) is the most common cause of childhood congenital blindness in developed nations, yet the fundamental pathobiology of ONH remains unknown. The objective of this study was to employ a ‘face validated' murine model to determine the timing of onset and the pathologic characteristics of ONH. Methods Based on the robust linkage between X-linked CASK haploinsufficiency and clinically diagnosed ONH, we hypothesized that heterozygous deletion of CASK (CASK(+/−)) in rodents will produce an optic nerve pathology closely recapitulating ONH. We quantitatively analyzed the entire subcortical visual system in female CASK(+/−) mice using immunohistochemistry, anterograde axonal tracing, toluidine blue staining, transmission electron microscopy, and serial block-face scanning electron microscopy. Results CASK haploinsuffiency in mice phenocopies human ONH with complete penetrance, thus satisfying the ‘face validity'. We demonstrate that the optic nerve in CASK(+/−) mice is not only thin, but is comprised of atrophic retinal axons and displays reactive astrogliosis. Myelination of the optic nerve axons remains unchanged. Moreover, we demonstrate a significant decrease in retinal ganglion cell (RGC) numbers and perturbation in retinothalamic connectivity. Finally, we used this mouse model to define the onset and progression of ONH pathology, demonstrating for the first time that optic nerve defects arise at neonatally in CASK(+/−)mice. Conclusions Optic nerve hypoplasia is a complex neuropathology of the subcortical visual system involving RGC loss, axonopathy, and synaptopathy and originates at a developmental stage in mice that corresponds to the late third trimester development in humans.
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Affiliation(s)
- Chen Liang
- Developmental and Translational Neurobiology Center, Virginia Tech Carilion Research Institute, Roanoke, Virginia, United States.,Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, United States
| | - Alicia Kerr
- Developmental and Translational Neurobiology Center, Virginia Tech Carilion Research Institute, Roanoke, Virginia, United States.,Graduate Program in Translational Biology, Medicine, and Health, Virginia Tech, Blacksburg, Virginia, United States
| | - Yangfengzhong Qiu
- Developmental and Translational Neurobiology Center, Virginia Tech Carilion Research Institute, Roanoke, Virginia, United States
| | | | - Hilde Van Esch
- Center for Human Genetics, University Hospitals Leuven, Leuven, Belgium
| | - Michael A Fox
- Developmental and Translational Neurobiology Center, Virginia Tech Carilion Research Institute, Roanoke, Virginia, United States.,Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, United States
| | - Konark Mukherjee
- Developmental and Translational Neurobiology Center, Virginia Tech Carilion Research Institute, Roanoke, Virginia, United States.,Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, United States
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17
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Lens Biology is a Dimension of Neurobiology. Neurochem Res 2017; 42:933-942. [DOI: 10.1007/s11064-016-2156-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Revised: 12/12/2016] [Accepted: 12/19/2016] [Indexed: 01/02/2023]
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18
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Ehrhart F, Coort SLM, Cirillo E, Smeets E, Evelo CT, Curfs LMG. Rett syndrome - biological pathways leading from MECP2 to disorder phenotypes. Orphanet J Rare Dis 2016; 11:158. [PMID: 27884167 PMCID: PMC5123333 DOI: 10.1186/s13023-016-0545-5] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 11/17/2016] [Indexed: 02/07/2023] Open
Abstract
Rett syndrome (RTT) is a rare disease but still one of the most abundant causes for intellectual disability in females. Typical symptoms are onset at month 6-18 after normal pre- and postnatal development, loss of acquired skills and severe intellectual disability. The type and severity of symptoms are individually highly different. A single mutation in one gene, coding for methyl-CpG-binding protein 2 (MECP2), is responsible for the disease. The most important action of MECP2 is regulating epigenetic imprinting and chromatin condensation, but MECP2 influences many different biological pathways on multiple levels although the molecular pathways from gene to phenotype are currently not fully understood. In this review the known changes in metabolite levels, gene expression and biological pathways in RTT are summarized, discussed how they are leading to some characteristic RTT phenotypes and therefore the gaps of knowledge are identified. Namely, which phenotypes have currently no mechanistic explanation leading back to MECP2 related pathways? As a result of this review the visualization of the biologic pathways showing MECP2 up- and downstream regulation was developed and published on WikiPathways which will serve as template for future omics data driven research. This pathway driven approach may serve as a use case for other rare diseases, too.
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Affiliation(s)
- Friederike Ehrhart
- Governor Kremers Centre - Rett Expertise Centre, Maastricht University Medical Center, Maastricht, The Netherlands. .,Department of Bioinformatics, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University, Maastricht, The Netherlands.
| | - Susan L M Coort
- Department of Bioinformatics, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University, Maastricht, The Netherlands
| | - Elisa Cirillo
- Department of Bioinformatics, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University, Maastricht, The Netherlands
| | - Eric Smeets
- Governor Kremers Centre - Rett Expertise Centre, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Chris T Evelo
- Governor Kremers Centre - Rett Expertise Centre, Maastricht University Medical Center, Maastricht, The Netherlands.,Department of Bioinformatics, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University, Maastricht, The Netherlands
| | - Leopold M G Curfs
- Governor Kremers Centre - Rett Expertise Centre, Maastricht University Medical Center, Maastricht, The Netherlands
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Rapid and Objective Assessment of Neural Function in Autism Spectrum Disorder Using Transient Visual Evoked Potentials. PLoS One 2016; 11:e0164422. [PMID: 27716799 PMCID: PMC5055293 DOI: 10.1371/journal.pone.0164422] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Accepted: 09/23/2016] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVE There is a critical need to identify biomarkers and objective outcome measures that can be used to understand underlying neural mechanisms in autism spectrum disorder (ASD). Visual evoked potentials (VEPs) offer a noninvasive technique to evaluate the functional integrity of neural mechanisms, specifically visual pathways, while probing for disease pathophysiology. METHODS Transient VEPs (tVEPs) were obtained from 96 unmedicated children, including 37 children with ASD, 36 typically developing (TD) children, and 23 unaffected siblings (SIBS). A conventional contrast-reversing checkerboard condition was compared to a novel short-duration condition, which was developed to enable objective data collection from severely affected populations who are often excluded from electroencephalographic (EEG) studies. RESULTS Children with ASD showed significantly smaller amplitudes compared to TD children at two of the earliest critical VEP components, P60-N75 and N75-P100. SIBS showed intermediate responses relative to ASD and TD groups. There were no group differences in response latency. Frequency band analyses indicated significantly weaker responses for the ASD group in bands encompassing gamma-wave activity. Ninety-two percent of children with ASD were able to complete the short-duration condition compared to 68% for the standard condition. CONCLUSIONS The current study establishes the utility of a short-duration tVEP test for use in children at varying levels of functioning and describes neural abnormalities in children with idiopathic ASD. Implications for excitatory/inhibitory balance as well as the potential application of VEP for use in clinical trials are discussed.
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Abstract
Investigators from the Boston Children's Hospital recorded pattern-reversal visual evoked potentials (VEPs) in Mecp2 heterozygous female mice and in 34 girls with Rett syndrome (RTT).
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Affiliation(s)
- J Gordon Millichap
- Division of Neurology, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL; Departments of Pediatrics and Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL
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21
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LeBlanc JJ, DeGregorio G, Centofante E, Vogel-Farley VK, Barnes K, Kaufmann WE, Fagiolini M, Nelson CA. Visual evoked potentials detect cortical processing deficits in Rett syndrome. Ann Neurol 2015; 78:775-86. [PMID: 26332183 DOI: 10.1002/ana.24513] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Revised: 08/07/2015] [Accepted: 08/26/2015] [Indexed: 01/26/2023]
Abstract
OBJECTIVE Rett syndrome (RTT) is a neurodevelopmental disorder caused by mutation of the X-linked MECP2 gene and characterized by developmental regression during the first few years of life. The objective of this study was to investigate if the visual evoked potential (VEP) could be used as an unbiased, quantitative biomarker to monitor brain function in RTT. METHODS We recorded pattern-reversal VEPs in Mecp2 heterozygous female mice and 34 girls with RTT. The amplitudes and latencies of VEP waveform components were quantified, and were related to disease stage, clinical severity, and MECP2 mutation type in patients. Visual acuity was also assessed in both mice and patients by modulating the spatial frequency of the stimuli. RESULTS Mecp2 heterozygous female mice and RTT patients exhibited a similar decrease in VEP amplitude that was most striking in the later stages of the disorder. RTT patients also displayed a slower recovery from the principal peak of the VEP response that was impacted by MECP2 mutation type. When the spatial frequency of the stimulus was increased, both patients and mice displayed a deficit in discriminating smaller patterns, indicating lower visual spatial acuity in RTT. INTERPRETATION VEP is a method that can be used to assess brain function across species and in children with severe disabilities like RTT. Our findings support the introduction of standardized VEP analysis in clinical and research settings to probe the neurobiological mechanism underlying functional impairment and to longitudinally monitor progression of the disorder and response to treatment.
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Affiliation(s)
- Jocelyn J LeBlanc
- Laboratories of Cognitive Neuroscience, Division of Developmental Medicine, Boston Children's Hospital, Boston.,F. M. Kirby Neurobiology Center, Department of Neurology, Boston Children's Hospital, Boston.,Harvard Medical School, Boston
| | - Geneva DeGregorio
- Laboratories of Cognitive Neuroscience, Division of Developmental Medicine, Boston Children's Hospital, Boston
| | - Eleonora Centofante
- F. M. Kirby Neurobiology Center, Department of Neurology, Boston Children's Hospital, Boston
| | - Vanessa K Vogel-Farley
- Laboratories of Cognitive Neuroscience, Division of Developmental Medicine, Boston Children's Hospital, Boston
| | - Katherine Barnes
- Rett Syndrome Program, Department of Neurology, Boston Children's Hospital, Boston
| | - Walter E Kaufmann
- Harvard Medical School, Boston.,Rett Syndrome Program, Department of Neurology, Boston Children's Hospital, Boston
| | - Michela Fagiolini
- F. M. Kirby Neurobiology Center, Department of Neurology, Boston Children's Hospital, Boston.,Harvard Medical School, Boston
| | - Charles A Nelson
- Laboratories of Cognitive Neuroscience, Division of Developmental Medicine, Boston Children's Hospital, Boston.,Harvard Medical School, Boston.,Harvard Graduate School of Education, Cambridge, MA
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22
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Durand S, Patrizi A, Quast KB, Hachigian L, Pavlyuk R, Saxena A, Carninci P, Hensch TK, Fagiolini M. NMDA receptor regulation prevents regression of visual cortical function in the absence of Mecp2. Neuron 2013; 76:1078-90. [PMID: 23259945 DOI: 10.1016/j.neuron.2012.12.004] [Citation(s) in RCA: 115] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/03/2012] [Indexed: 10/27/2022]
Abstract
Brain function is shaped by postnatal experience and vulnerable to disruption of Methyl-CpG-binding protein, Mecp2, in multiple neurodevelopmental disorders. How Mecp2 contributes to the experience-dependent refinement of specific cortical circuits and their impairment remains unknown. We analyzed vision in gene-targeted mice and observed an initial normal development in the absence of Mecp2. Visual acuity then rapidly regressed after postnatal day P35-40 and cortical circuits largely fell silent by P55-60. Enhanced inhibitory gating and an excess of parvalbumin-positive, perisomatic input preceded the loss of vision. Both cortical function and inhibitory hyperconnectivity were strikingly rescued independent of Mecp2 by early sensory deprivation or genetic deletion of the excitatory NMDA receptor subunit, NR2A. Thus, vision is a sensitive biomarker of progressive cortical dysfunction and may guide novel, circuit-based therapies for Mecp2 deficiency.
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Affiliation(s)
- Severine Durand
- FM Kirby Neurobiology Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115, USA
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Eyes on DNA methylation: current evidence for DNA methylation in ocular development and disease. J Ocul Biol Dis Infor 2012; 4:95-103. [PMID: 23538551 DOI: 10.1007/s12177-012-9078-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2011] [Accepted: 03/05/2012] [Indexed: 12/20/2022] Open
Abstract
Epigenetic modulation of chromatin states constitutes a vital component of the cellular repertoire of transcriptional regulatory mechanisms. The development of new technologies capable of generating genome-wide maps of chromatin modifications has re-energized the field. We are now poised to determine how species- and tissue-specific patterns of DNA methylation, in concert with other chromatin modifications, function to establish and maintain cell- and tissue-specific patterns of gene expression during normal development, cellular differentiation, and disease. This review addresses our current understanding of the major mechanisms and function of DNA methylation in vertebrates with a historical perspective and an emphasis on what is known about DNA methylation in eye development and disease.
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De Felice C, Signorini C, Durand T, Oger C, Guy A, Bultel-Poncé V, Galano JM, Ciccoli L, Leoncini S, D'Esposito M, Filosa S, Pecorelli A, Valacchi G, Hayek J. F2-dihomo-isoprostanes as potential early biomarkers of lipid oxidative damage in Rett syndrome. J Lipid Res 2011; 52:2287-2297. [PMID: 21917727 DOI: 10.1194/jlr.p017798] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Oxidative damage has been reported in Rett syndrome (RTT), a pervasive developmental disorder caused in up to 95% of cases by mutations in the X-linked methyl-CpG binding protein 2 gene. Herein, we have synthesized F(2)-dihomo-isoprostanes (F(2)-dihomo-IsoPs), peroxidation products from adrenic acid (22:4 n-6), a known component of myelin, and tested the potential value of F(2)-dihomo-IsoPs as a novel disease marker and its relationship with clinical presentation and disease progression. F(2)-dihomo-IsoPs were determined by gas chromatography/negative-ion chemical ionization tandem mass spectrometry. Newly synthesized F(2)-dihomo-IsoP isomers [ent-7(RS)-F(2t)-dihomo-IsoP and 17-F(2t)-dihomo-IsoP] were used as reference standards. The measured ions were the product ions at m/z 327 derived from the [M-181](-) precursor ions (m/z 597) produced from both the derivatized ent-7(RS)-F(2t)-dihomo-IsoP and 17-F(2t)-dihomo-IsoP. Average plasma F(2)-dihomo-IsoP levels in RTT were about one order of magnitude higher than those in healthy controls, being higher in typical RTT as compared with RTT variants, with a remarkable increase of about two orders of magnitude in patients at the earliest stage of the disease followed by a steady decrease during the natural clinical progression. hese data indicate for the first time that quantification of F(2)-dihomo-IsoPs in plasma represents an early marker of the disease and may provide a better understanding of the pathogenic mechanisms behind the neurological regression in patients with RTT.
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Affiliation(s)
- Claudio De Felice
- Neonatal Intensive Care Unit, Azienda Ospedaliera Universitaria Senese, Siena, Italy.
| | - Cinzia Signorini
- Department of Pathophysiology, Experimental Medicine, and Public Health, University of Siena, Siena, Italy
| | - Thierry Durand
- Institut des Biomolécules Max Mousseron, UMR 5247 CNRS - UM I - UM II, Montpellier, France
| | - Camille Oger
- Institut des Biomolécules Max Mousseron, UMR 5247 CNRS - UM I - UM II, Montpellier, France
| | - Alexandre Guy
- Institut des Biomolécules Max Mousseron, UMR 5247 CNRS - UM I - UM II, Montpellier, France
| | - Valérie Bultel-Poncé
- Institut des Biomolécules Max Mousseron, UMR 5247 CNRS - UM I - UM II, Montpellier, France
| | - Jean-Marie Galano
- Institut des Biomolécules Max Mousseron, UMR 5247 CNRS - UM I - UM II, Montpellier, France
| | - Lucia Ciccoli
- Department of Pathophysiology, Experimental Medicine, and Public Health, University of Siena, Siena, Italy
| | - Silvia Leoncini
- Department of Pathophysiology, Experimental Medicine, and Public Health, University of Siena, Siena, Italy
| | - Maurizio D'Esposito
- Institute of Genetics and Biophysics "Adriano Buzzati Traverso," CNR, Napoli, Italy; Istituto Neurologico Mediterraneo Neuromed, Pozzilli, Italy
| | - Stefania Filosa
- Institute of Genetics and Biophysics "Adriano Buzzati Traverso," CNR, Napoli, Italy; Istituto Neurologico Mediterraneo Neuromed, Pozzilli, Italy
| | - Alessandra Pecorelli
- Department of Pathophysiology, Experimental Medicine, and Public Health, University of Siena, Siena, Italy
| | - Giuseppe Valacchi
- Department of Food and Nutrition, Kyung Hee University, Seoul, Korea; Department of Evolutionary Biology, University of Ferrara, Ferrara, Italy; and
| | - Joussef Hayek
- Child Neuropsychiatry Unit, University Hospital, Azienda Ospedaliera Universitaria Senese, Siena, Italy
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Ocular MECP2 protein expression in patients with and without Rett syndrome. Pediatr Neurol 2010; 43:35-40. [PMID: 20682201 PMCID: PMC2916867 DOI: 10.1016/j.pediatrneurol.2010.02.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2009] [Revised: 09/08/2009] [Accepted: 02/22/2010] [Indexed: 02/03/2023]
Abstract
Rett syndrome is a neurodevelopmental disorder caused by mutations in the methyl CpG binding protein 2 gene (MECP2). The MECP2 protein is expressed primarily in neurons, and mutations in the gene lead to the clinical features of Rett syndrome in human patients and neurologic deficits in murine models. Visual function is relatively preserved in Rett syndrome patients, but the cause is unknown. The eyes of two Rett syndrome patients who died of the disease were analyzed; no gross or microscopic changes were found. MECP2 expression was examined using immunohistochemistry; nuclear protein expression was largely limited to ganglion cells and the portion of the inner nuclear layer populated by amacrine cells. No significant differences in MECP2 protein level or distribution were identified in the two eyes from the Rett syndrome patients, compared with 11 controls. The findings were compared with MECP2 expression in the brain of these two subjects and in MECP2-deficient mice. The findings suggest that the normally limited expression of MECP2 in visual pathway neurons may underlie the intact vision observed in Rett syndrome.
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Larsson G, Lindström B, Engerström IW. Rett syndrome from a family perspective: The Swedish Rett Center survey. Brain Dev 2005; 27 Suppl 1:S14-S19. [PMID: 16182488 DOI: 10.1016/j.braindev.2005.03.015] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2005] [Revised: 01/27/2005] [Accepted: 03/05/2005] [Indexed: 11/16/2022]
Abstract
The aim of this study was to make a description of the early development in individuals with the diagnosis Rett syndrome using parents' information. Information received from 125 cases of Rett syndrome in Sweden in 1997 provided us with families' description of early development in gross motor function, fine motor function and communication/social interplay. Best abilities before regression were presented, 62% lost their best abilities, 22% kept them and 5% kept them with deterioration. Seventy-three percent learnt to walk, 20% stopped walking and 2% retrained walking. Concerning feeding, 69% learnt to feed themselves, 57% lost this ability, 7% retrained the ability and 5% learnt to feed after regression. Sixty-four percent were one year or younger when there was a deviation in development. Sixty answers reported the girl was late in developing functions while 35 reported sudden loss of reached abilities. Seventy-four percent developed a scoliosis and 83% reported other deformities; of these, deformities in feet were the most common. Postural control was poor since all but 15 girls/women learnt in different directions when sitting. Transitional movements were difficult to perform. In 80% of cases, the families were those who suspected early that something was wrong in the child's development. Because of this it is essential that medical staff is aware of the different ways RS develops in order to give families early appropriate support and a plan for intervention. Since there is not only loss of function in this group but also kept abilities, retrained abilities and abilities achieved after regression, more research has to be focused on management and treatment to help persons with Rett syndrome keep and develop abilities according to their individual resources.
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Affiliation(s)
- Gunilla Larsson
- Swedish Rett Center, Frösö Strand, Box 601, SE-832 23 Frösön, Sweden.
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27
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Abstract
Rett syndrome is a neurodevelopmental disorder that in most cases is consequent to a mutation in the MECP2 gene. The central nervous system is the primary organ system involved in Rett syndrome. Neurophysiologic evaluations provide information concerning the developmental aspects of Rett syndrome and the character and extent of involvement of the central, peripheral, and autonomic nervous system pathways. Evoked potentials typically demonstrate intactness of peripheral auditory and visual pathways and suggest dysfunction of central or "higher" cortical pathways. Somatosensory evoked potentials can be characterized by "giant" responses, suggesting cortical hyperexcitability. Cortical hyperexcitability is further suggested by the findings of the electroencephalogram (EEG), which are primarily characterized by a loss of expected developmental features; the appearance of focal, multifocal, and generalized epileptiform abnormalities; and the occurrence of rhythmic slow (theta) activity, primarily in the frontal-central regions. Epileptic seizures are reported to occur frequently in Rett syndrome. However, many events presumed to be seizures have no EEG correlate during video-EEG monitoring. Impairment of the autonomic nervous system in Rett syndrome is suggested by an increased incidence of long Q-T intervals during electrocardiographic recordings and diminished heart rate variability. Autonomic nervous system dysfunction can contribute to the increased incidence of sudden unexpected death in Rett syndrome.
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Affiliation(s)
- Daniel G Glaze
- Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA.
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28
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Jackson AJ, Saunders KJ. The optometric assessment of the visually impaired infant and young child. Ophthalmic Physiol Opt 2002. [DOI: 10.1111/j.0275-5408.1999.tb00018.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- A. Jonathan Jackson
- Department of OphthalmologyRoyal Victoria Hospital/Queens UniversityBelfastBT12 6DANorthern IrelandUK
- Department of OptometryUniversity of UlsterColeraineNorthern IrelandUK
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Glaze DG. Neurophysiology of Rett syndrome. MENTAL RETARDATION AND DEVELOPMENTAL DISABILITIES RESEARCH REVIEWS 2002; 8:66-71. [PMID: 12112729 DOI: 10.1002/mrdd.10024] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Neurophysiological evaluations have been widely applied in the study of Rett syndrome (RS) to provide information concerning the developmental aspects of RS; the character and extent of involvement of the central, peripheral, and autonomic nervous system pathways; and evaluation of the clinical symptomatology of RS. The electroencephalogram (EEG) is invariably abnormal and shows characteristic, though not diagnostic, changes: loss of expected developmental features; the appearance of focal, multifocal, and generalized epileptiform abnormalities; and the occurrence of rhythmic slow (theta) activity primarily in the frontal-central regions. Epileptic seizures are reported to occur frequently in RS, and partial and generalized seizures may be experienced by RS girls. However, many events presumed to be seizures have no EEG correlate during video-EEG monitoring, suggesting the possibility of a nonepileptic mechanism. Such monitoring may be necessary to determine appropriate use of antiepileptic drugs. Evoked potentials typically demonstrate intact peripheral auditory and visual pathways and suggest dysfunction of central or "higher" cortical pathways. Somatosensory-evoked potentials may be characterized by "giant" responses, suggesting cortical hyperexcitability. An increased incidence of long QT intervals during electrocardiographic recordings and diminished heart-rate variability, suggesting impairment of the autonomic nervous system, are described in RS. With the discovery of the genetic basis of RS, neurophysiological studies will provide parameters for phenotype-genotype correlations and characterization of animal models.
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Affiliation(s)
- Daniel G Glaze
- Departments of Pediatrics and Neurology, Baylor College of Medicine, Houston, Texas 77030, USA.
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Umansky R, Watson JS. Influence of eye movements on Rett stereotypies: evidence suggesting a stage-specific regression. J Child Neurol 1998; 13:158-62. [PMID: 9568758 DOI: 10.1177/088307389801300402] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The influence of eye movements on hand use and pervasive stereotypies in Rett syndrome was studied, to better understand the developmental abnormality in this disorder. Nine patients in the post-regression phase were offered objects. As expected, the girls looked at the objects but usually did not reach for them. Nor were their characteristic hand stereotypies altered by such looking. But the occurrence of stereotypies was promoted by overall shifts in gaze, ie, eye movements in any direction. This finding may be relevant to the late-infancy loss of voluntary hand use in Rett syndrome associated with onset of pervasive stereotypies. It suggests a stage-specific regression to a level characteristic of normal 3-month-old infants who do not reach and grasp, but whose hand clasping and mouthing may be triggered by the perceptual consequences of exploratory eye movements and shifts in gaze.
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Affiliation(s)
- R Umansky
- Child Development Center, Children's Hospital Oakland, CA 94609, USA
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31
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Nezu A, Kimura S, Takeshita S, Tanaka M. Characteristic response to transcranial magnetic stimulation in Rett syndrome. ELECTROENCEPHALOGRAPHY AND CLINICAL NEUROPHYSIOLOGY 1998; 109:100-3. [PMID: 9741799 DOI: 10.1016/s0924-980x(97)00081-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
To pathophysiologically evaluate the corticospinal tracts (CSTs) in Rett syndrome (RS), transcranial magnetic stimulation (TMS) was performed in 3 patients aged 4, 6 and 13 years. The two younger cases exhibited the clinical characteristics of the pseudostationary stage (stage III), while ambulation was lost in the oldest case at the age of 11 years (stage IV). The motor cortex and cervical spinal roots were magnetically stimulated to obtain motor evoked potentials (MEPs) from the relaxed first dorsal interosseous muscle. Compared with the central motor conduction time (CMCT) in age-matched normal children, CMCT in the stage III cases was significantly short (6.9-7.1 ms, P < 0.05). In the stage IV case, CMCT was markedly short but not significantly so (6.6 ms, P = 0.06), which was partly due to a significant increase in the threshold intensity of TMS (100%, P < 0.05). Thus, the CMCT shortening, which implied unique cortical hyperexcitability, was considered consistent and characteristic of RS. The CSTs in the stage IV case were certainly impaired, corresponding well to the progressive spastic paresis.
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Affiliation(s)
- A Nezu
- Department of Pediatrics, Urafune Hospital of Yokohama City University School of Medicine, Yokohama, Japan
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Abstract
Nine girls with Rett syndrome (mean age, 10.1 years) were monitored 24 hours a day over a period of 10 weeks using wrist actigraphy. Baseline sleep-wake patterns were assessed for 1 week. Subsequently, patients underwent a 4-week melatonin treatment period in a double-blind, placebo-controlled, crossover protocol that employed a 1-week washout between treatment trials. Melatonin doses ranged from 2.5 to 7.5 mg, based upon individual body weight. Baseline sleep quality was poor compared with healthy children. At baseline the group demonstrated a low sleep efficiency (mean [+/- SE], 68.0+/-3.9%), long sleep-onset latency (42.1+/-12.0 minutes), and a short and fragmented total sleep time (7.5+/-0.3 hours; 15+/-2 awakenings per night). Melatonin significantly decreased sleep-onset latency to (mean +/- SE) 19.1+/-5.3 minutes (P<0.05) during the first 3 weeks of treatment. While the variability of individual responsiveness was high, melatonin appeared to improve total sleep time and sleep efficiency in the patients with the worse baseline sleep quality. Finally, a 4-week administration of melatonin appears to be a safe treatment as no adverse side effects were detected, yet long-term effects of chronic melatonin use in pediatric patients are unknown at this time.
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Affiliation(s)
- A J McArthur
- Department of Psychiatry, Oregon Health Sciences University, Portland 97201-3098, USA
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Mackie RT, McCulloch DL, Bradnam MS, Glegg M, Evans AL. The effect of motion on pattern-onset visual evoked potentials in adults and children. Doc Ophthalmol 1995; 91:371-80. [PMID: 8899307 DOI: 10.1007/bf01214655] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Visual evoked potentials can be elicited by a variety of visual stimuli, including pattern-onset and motion-onset. It may be desirable to combine pattern-onset with motion-onset stimuli, for example, to make a direct comparison between optokinetic nystagmus and visual evoked potential acuity thresholds. Both procedures employ grating stimuli; however, the gratings must be moving to produce optokinetic nystagmus. We compared pattern-onset visual evoked potentials with both a static and a moving pattern to investigate the effect of motion on the pattern-onset visual evoked potential waveform. Visual evoked potential recordings were made from 10 adults (aged 20-37 years) and 10 children (aged 5-7 years) with the active electrode at Oz. Stimuli consisted of onset of high-contrast vertical bars of three sizes (12', 30' and 60') both with and without motion (3 cycles/s). In a subgroup of subjects, visual evoked potentials were recorded to motion onset of constantly present gratings. Motion of the pattern had no significant effect on any of the latency components of the visual evoked potential waveform in adults or children. The amplitude of the C2-C3 component was significantly increased (p < 0.001) in adults. The motion appears to add a late negative component to the visual evoked potential similar to that produced by the motion-only stimulus. The latency of the early components of the pattern-onset visual evoked potential was unaffected by the presence of motion. Therefore, pattern-onset visual evoked potentials with moving gratings could be used to estimate visual acuity, and direct comparisons could be made between visual evoked potential and optokinetic nystagmus acuity thresholds with the use of the same stimulus parameters.
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Affiliation(s)
- R T Mackie
- Department of Vision Sciences, Glasgow Caledonian University, UK
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