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Pollini L, van der Veen S, Elting JWJ, Tijssen MAJ. Negative Myoclonus: Neurophysiological Study and Clinical Impact in Progressive Myoclonus Ataxia. Mov Disord 2024; 39:674-683. [PMID: 38385661 DOI: 10.1002/mds.29741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2023] [Revised: 01/13/2024] [Accepted: 01/25/2024] [Indexed: 02/23/2024] Open
Abstract
INTRODUCTION Negative myoclonus (NM) is an involuntary movement caused by a sudden interruption of muscular activity, resulting in gait problems and falls. OBJECTIVE To establish frequency, clinical impact, and neurophysiology of NM in progressive myoclonus ataxia (PMA) patients. METHODS Clinical, neurophysiological, and genetic data of 14 PMA individuals from University Medical Centre Groningen (UMCG) Expertise Center Movement Disorder Groningen were retrospectively collected. Neurophysiological examination included video-electromyography-accelerometry assessment in all patients and electroencephalography (EEG) examination in 13 individuals. Jerk-locked (or silent period-locked) back-averaging and cortico-muscular coherence (CMC) analysis aided the classification of myoclonus. RESULTS NM was present in 6 (NM+) and absent in 8 (NM-) PMA patients. NM+ individuals have more frequent falls (100% vs. 37.5%) and higher scores on the Gross Motor Function Classification System (GMFCS) (4.3 ±0.74 vs. 2.5 ±1.2) than NM- individuals. Genetic background of NM+ included GOSR2 and SEMA6B, while that of NM- included ATM, KCNC3, NUS1, STPBN2, and GOSR2. NM was frequently preceded by positive myoclonus (PM) and silent-period length was between 88 and 194 ms. EEG epileptiform discharges were associated with NM in 2 cases. PM was classified as cortical in 5 NM+ and 2 NM- through EEG inspection, jerk-locked back-averaging, or CMC analysis. DISCUSSION Neurophysiological examination is crucial for detecting NM that could be missed on clinical examination due to a preceding PM. Evidence points to a cortical origin of NM, an association with more severe motor phenotype, and suggests the presence of genetic disorders causing either a PMA or progressive myoclonus epilepsy, rather than pure PMA phenotype. © 2024 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Luca Pollini
- Department of Human Neuroscience, Sapienza University of Rome, Rome, Italy
- Department of Neurology, University of Groningen, University Medical Centre Groningen (UMCG), Groningen, The Netherlands
- Expertise Centre Movement Disorders Groningen, University Medical Centre Groningen (UMCG), Groningen, The Netherlands
| | - Sterre van der Veen
- Department of Neurology, University of Groningen, University Medical Centre Groningen (UMCG), Groningen, The Netherlands
- Expertise Centre Movement Disorders Groningen, University Medical Centre Groningen (UMCG), Groningen, The Netherlands
| | - Jan Willem J Elting
- Department of Neurology, University of Groningen, University Medical Centre Groningen (UMCG), Groningen, The Netherlands
- Expertise Centre Movement Disorders Groningen, University Medical Centre Groningen (UMCG), Groningen, The Netherlands
- Department of Clinical Neurophysiology, University of Groningen, University Medical Center Groningen (UMCG), Groningen, The Netherlands
| | - Marina A J Tijssen
- Department of Neurology, University of Groningen, University Medical Centre Groningen (UMCG), Groningen, The Netherlands
- Expertise Centre Movement Disorders Groningen, University Medical Centre Groningen (UMCG), Groningen, The Netherlands
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Zimmern V, Minassian B. Progressive Myoclonus Epilepsy: A Scoping Review of Diagnostic, Phenotypic and Therapeutic Advances. Genes (Basel) 2024; 15:171. [PMID: 38397161 PMCID: PMC10888128 DOI: 10.3390/genes15020171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 01/23/2024] [Accepted: 01/26/2024] [Indexed: 02/25/2024] Open
Abstract
The progressive myoclonus epilepsies (PME) are a diverse group of disorders that feature both myoclonus and seizures that worsen gradually over a variable timeframe. While each of the disorders is individually rare, they collectively make up a non-trivial portion of the complex epilepsy and myoclonus cases that are seen in tertiary care centers. The last decade has seen substantial progress in our understanding of the pathophysiology, diagnosis, prognosis, and, in select disorders, therapies of these diseases. In this scoping review, we examine English language publications from the past decade that address diagnostic, phenotypic, and therapeutic advances in all PMEs. We then highlight the major lessons that have been learned and point out avenues for future investigation that seem promising.
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Affiliation(s)
- Vincent Zimmern
- Division of Child Neurology, University of Texas Southwestern, Dallas, TX 75390, USA;
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Pollari E, Tegelberg S, Björklund H, Kälviäinen R, Lehesjoki AE, Haapalinna A. In depth behavioral phenotyping unravels complex motor disturbances in Cstb-/- mouse, a model for progressive myoclonus epilepsy type 1. Front Behav Neurosci 2023; 17:1325051. [PMID: 38179183 PMCID: PMC10764494 DOI: 10.3389/fnbeh.2023.1325051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Accepted: 12/01/2023] [Indexed: 01/06/2024] Open
Abstract
Progressive myoclonus epilepsy type 1 (EPM1) is an autosomal recessively inherited childhood-adolescence onset neurodegenerative disease caused by mutations in the cystatin B (CSTB gene). The key clinical manifestation in EPM1 is progressive, stimulus-sensitive, in particular action-induced myoclonus. The cystatin B-deficient mouse model, Cstb-/-, has been described to present with myoclonic seizures and progressive ataxia. Here we describe results from in-depth behavioral phenotyping of the Cstb-/- mouse model in pure isogenic 129S2/SvHsd background covering ages from 1.5 to 6 months. We developed a method for software-assisted detection of myoclonus from video recordings of the Cstb-/- mice. Additionally, we observed that the mice were hyperactive and showed reduced startle response, problems in motor coordination and lack of inhibition. We were, however, not able to demonstrate an ataxic phenotype in them. This detailed behavioral phenotyping of the Cstb-/- mice reveals new aspects of this mouse model. The nature of the motor problems in the Cstb-/- mice seems to be more complex and more resembling the human phenotype than initially described.
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Affiliation(s)
| | - Saara Tegelberg
- Folkhälsan Research Center and Medicum, Medical Faculty, University of Helsinki, Helsinki, Finland
| | | | - Reetta Kälviäinen
- Epilepsy Center, Neuro Center, Kuopio University Hospital, Kuopio, Finland
- Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland
| | - Anna-Elina Lehesjoki
- Folkhälsan Research Center and Medicum, Medical Faculty, University of Helsinki, Helsinki, Finland
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Sinokki A, Säisänen L, Hyppönen J, Silvennoinen K, Kälviäinen R, Mervaala E, Karjalainen PA, Rissanen SM. Detecting negative myoclonus during long-term home measurements using wearables. Clin Neurophysiol 2023; 156:166-174. [PMID: 37952446 DOI: 10.1016/j.clinph.2023.10.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 08/22/2023] [Accepted: 10/17/2023] [Indexed: 11/14/2023]
Abstract
OBJECTIVE The aim of this study was to develop a feasible method for the detection of negative myoclonus (NM) through long-term home measurements in patients with progressive myoclonus epilepsy type 1. METHODS The number and duration of silent periods (SP) associated with NM were detected during a 48 h home recording using wearable surface electromyography (EMG) sensors. RESULTS A newly developed algorithm was able to find short (50-69 ms), intermediate (70-100 ms), and long (101- 500 ms) SPs from EMG data. Negative myoclonus assessed by the algorithm correlated significantly with the video-recorded and physician-evaluated unified myoclonus rating scale (UMRS) scores of NM and action myoclonus. Silent period duration, number, and their combination, correlated strongly and significantly also with the Singer score, which assesses functional status and ambulation. CONCLUSIONS Negative myoclonus can be determined objectively using long-term EMG measurements in home environment. With long-term measurements, we can acquire more reliable quantified information about NM as a symptom, compared to short evaluation at the clinic. SIGNIFICANCE As measured using SPs, NM may be a clinically useful measure for monitoring disease progression or assessing antimyoclonic drug effects objectively.
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Affiliation(s)
- Aku Sinokki
- Department of Technical Physics, University of Eastern Finland, Kuopio, Finland.
| | - Laura Säisänen
- Department of Technical Physics, University of Eastern Finland, Kuopio, Finland; Kuopio Epilepsy Center, Department of Clinical Neurophysiology, Kuopio University Hospital, Full Member of ERN EpiCARE, Kuopio, Finland
| | - Jelena Hyppönen
- Kuopio Epilepsy Center, Department of Clinical Neurophysiology, Kuopio University Hospital, Full Member of ERN EpiCARE, Kuopio, Finland; Institute of Clinical Medicine, School of Medicine, Faculty of Health Sciences, University of Eastern Finland, Kuopio, Finland
| | - Katri Silvennoinen
- Kuopio Epilepsy Center, Neurocenter, Kuopio University Hospital, Full Member of ERN EpiCARE, Kuopio, Finland; Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, United Kingdom
| | - Reetta Kälviäinen
- Institute of Clinical Medicine, School of Medicine, Faculty of Health Sciences, University of Eastern Finland, Kuopio, Finland; Kuopio Epilepsy Center, Neurocenter, Kuopio University Hospital, Full Member of ERN EpiCARE, Kuopio, Finland
| | - Esa Mervaala
- Kuopio Epilepsy Center, Department of Clinical Neurophysiology, Kuopio University Hospital, Full Member of ERN EpiCARE, Kuopio, Finland; Institute of Clinical Medicine, School of Medicine, Faculty of Health Sciences, University of Eastern Finland, Kuopio, Finland
| | - Pasi A Karjalainen
- Department of Technical Physics, University of Eastern Finland, Kuopio, Finland
| | - Saara M Rissanen
- Department of Technical Physics, University of Eastern Finland, Kuopio, Finland; Adamant Health Ltd, Kuopio, Finland
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Meritam Larsen P, Beniczky S. Non-electroencephalogram-based seizure detection devices: State of the art and future perspectives. Epilepsy Behav 2023; 148:109486. [PMID: 37857030 DOI: 10.1016/j.yebeh.2023.109486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Revised: 10/06/2023] [Accepted: 10/07/2023] [Indexed: 10/21/2023]
Abstract
INTRODUCTION AND PURPOSE The continuously expanding research and development of wearable devices for automated seizure detection in epilepsy uses mostly non-invasive technology. Real-time alarms, triggered by seizure detection devices, are needed for safety and prevention to decrease seizure-related morbidity and mortality, as well as objective quantification of seizure frequency and severity. Our review strives to provide a state-of-the-art on automated seizure detection using non-invasive wearable devices in an ambulatory (home) environment and to highlight the prospects for future research. METHODS A joint working group of the International League Against Epilepsy (ILAE) and the International Federation of Clinical Neurophysiology (IFCN) recently published a clinical practice guideline on automated seizure detection using wearable devices. We updated the systematic literature search for the period since the last search by the joint working group. We selected studies qualifying minimally as phase-2 clinical validation trials, in accordance with standards for testing and validation of seizure detection devices. RESULTS High-level evidence (phases 3 and 4) is available only for the detection of tonic-clonic seizures and major motor seizures when using wearable devices based on accelerometry, surface electromyography (EMG), or a multimodal device combining accelerometry and heart rate. The reported sensitivity of these devices is 79.4-96%, with a false alarm rate of 0.20-1.92 per 24 hours (0-0.03 per night). A single phase-3 study validated the detection of absence seizures using a single-channel wearable EEG device. Two phase-4 studies showed overall user satisfaction with wearable seizure detection devices, which helped decrease injuries related to tonic-clonic seizures. Overall satisfaction, perceived sensitivity, and improvement in quality-of-life were significantly higher for validated devices. CONCLUSIONS Among the vast number of studies published on seizure detection devices, most are strongly affected by potential bias, providing a too-optimistic perspective. By applying the standards for clinical validation studies, potential bias can be reduced, and the quality of a continuously growing number of studies in this field can be assessed and compared. The ILAE-IFCN clinical practice guideline on automated seizure detection using wearable devices recommends using clinically validated wearable devices for automated detection of tonic-clonic seizures when significant safety concerns exist. The studies published after the guideline was issued only provide incremental knowledge and would not change the current recommendations.
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Affiliation(s)
- Pirgit Meritam Larsen
- Department of Clinical Neurophysiology, Danish Epilepsy Centre, Visbys Allé 5, 4293 Dianalund, Denmark.
| | - Sándor Beniczky
- Department of Clinical Neurophysiology, Danish Epilepsy Centre, Visbys Allé 5, 4293 Dianalund, Denmark; Department of Clinical Neurophysiology, Aarhus University Hospital, and Department of Clinical Medicine, Aarhus University, Palle Juul-Jensens Boulevard 165, 8200 Aarhus, Denmark.
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Silvennoinen K, Säisänen L, Hyppönen J, Rissanen SM, Karjalainen PA, D'Ambrosio S, Jimenez‐Jimenez D, Zagaglia S, Rothwell JC, Balestrini S, Sisodiya SM, Julkunen P, Mervaala E, Kälviäinen R. Short- and long-interval intracortical inhibition in EPM1 is related to genotype. Epilepsia 2023; 64:208-217. [PMID: 36398398 PMCID: PMC10107775 DOI: 10.1111/epi.17466] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 11/15/2022] [Accepted: 11/16/2022] [Indexed: 11/19/2022]
Abstract
OBJECTIVE Progressive myoclonic epilepsy type 1 (EPM1) is caused by biallelic alterations in the CSTB gene, most commonly dodecamer repeat expansions. Although transcranial magnetic stimulation (TMS)-induced long-interval intracortical inhibition (LICI) was previously reported to be normal in EPM1, short-interval intracortical inhibition (SICI) was reduced. We explored the association between these measures and the clinical and genetic features in a separate group of patients with EPM1. METHODS TMS combined with electromyography was performed under neuronavigation. LICI was induced with an inter-stimulus interval (ISI) of 100 ms, and SICI with ISIs of 2 and 3 ms, and their means (mSICIs) were expressed as the ratio of conditioned to unconditioned stimuli. LICI and mSICI were compared between patients and controls. Nonparametric correlation was used to study the association between inhibition and parameters of clinical severity, including the Unified Myoclonus Rating Scale (UMRS); among patients with EPM1 due to biallelic expansion repeats, also the association with the number of repeats was assessed. RESULTS The study protocol was completed in 19 patients (15 with biallelic expansion repeats and 4 compound heterozygotes), and 7 healthy, age- and sex-matched control participants. Compared to controls, patients demonstrated significantly less SICI (median mSICI ratio 1.18 vs 0.38; p < .001). Neither LICI nor SICI was associated with parameters of clinical severity. In participants with biallelic repeat expansions, the number of repeats in the more affected allele (greater repeat number [GRN]) correlated with LICI (rho = 0.872; p < .001) and SICI (rho = 0.689; p = .006). SIGNIFICANCE Our results strengthen the finding of deranged γ-aminobutyric acid (GABA)ergic inhibition in EPM1. LICI and SICI may have use as markers of GABAergic impairment in future trials of disease-modifying treatment in this condition. Whether a higher number of expansion repeats leads to greater GABAergic impairment warrants further study.
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Affiliation(s)
- Katri Silvennoinen
- Kuopio Epilepsy Center, NeurocenterMember of ERN EpiCARE, Kuopio University HospitalKuopioFinland
- Department of Clinical and Experimental EpilepsyUCL Queen Square Institute of NeurologyLondonUK
- Chalfont Centre for EpilepsyUK
| | - Laura Säisänen
- Department of Clinical Neurophysiology, Kuopio Epilepsy Center, NeurocenterMember of ERN EpiCARE, Kuopio University HospitalKuopioFinland
- Department of Applied PhysicsUniversity of Eastern FinlandKuopioFinland
| | - Jelena Hyppönen
- Department of Clinical Neurophysiology, Kuopio Epilepsy Center, NeurocenterMember of ERN EpiCARE, Kuopio University HospitalKuopioFinland
| | - Saara M. Rissanen
- Department of Applied PhysicsUniversity of Eastern FinlandKuopioFinland
| | | | - Sasha D'Ambrosio
- Department of Clinical and Experimental EpilepsyUCL Queen Square Institute of NeurologyLondonUK
- Dipartimento di Scienze Biomediche e Cliniche "L. Sacco"Università degli Studi di MilanoMilanItaly
| | - Diego Jimenez‐Jimenez
- Department of Clinical and Experimental EpilepsyUCL Queen Square Institute of NeurologyLondonUK
| | - Sara Zagaglia
- Department of Clinical and Experimental EpilepsyUCL Queen Square Institute of NeurologyLondonUK
| | - John C. Rothwell
- Sobell Department of Motor Neuroscience and Movement DisordersUCL Queen Square Institute of NeurologyLondonUK
| | - Simona Balestrini
- Department of Clinical and Experimental EpilepsyUCL Queen Square Institute of NeurologyLondonUK
- Chalfont Centre for EpilepsyUK
- Neuroscience DepartmentMember of ERN EpiCARE, Meyer Children HospitalFlorenceItaly
| | - Sanjay M. Sisodiya
- Department of Clinical and Experimental EpilepsyUCL Queen Square Institute of NeurologyLondonUK
- Chalfont Centre for EpilepsyUK
| | - Petro Julkunen
- Department of Clinical Neurophysiology, Kuopio Epilepsy Center, NeurocenterMember of ERN EpiCARE, Kuopio University HospitalKuopioFinland
- Department of Applied PhysicsUniversity of Eastern FinlandKuopioFinland
| | - Esa Mervaala
- Department of Clinical Neurophysiology, Kuopio Epilepsy Center, NeurocenterMember of ERN EpiCARE, Kuopio University HospitalKuopioFinland
- Institute of Clinical Medicine, School of Medicine, Faculty of Health SciencesUniversity of Eastern FinlandKuopioFinland
| | - Reetta Kälviäinen
- Kuopio Epilepsy Center, NeurocenterMember of ERN EpiCARE, Kuopio University HospitalKuopioFinland
- Institute of Clinical Medicine, School of Medicine, Faculty of Health SciencesUniversity of Eastern FinlandKuopioFinland
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