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Latorre A, Rocchi L, Paparella G, Manzo N, Bhatia KP, Rothwell JC. Changes in cerebellar output abnormally modulate cortical myoclonus sensorimotor hyperexcitability. Brain 2024; 147:1412-1422. [PMID: 37956080 PMCID: PMC10994547 DOI: 10.1093/brain/awad384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 10/07/2023] [Accepted: 11/02/2023] [Indexed: 11/15/2023] Open
Abstract
Cortical myoclonus is produced by abnormal neuronal discharges within the sensorimotor cortex, as demonstrated by electrophysiology. Our hypothesis is that the loss of cerebellar inhibitory control over the motor cortex, via cerebello-thalamo-cortical connections, could induce the increased sensorimotor cortical excitability that eventually causes cortical myoclonus. To explore this hypothesis, in the present study we applied anodal transcranial direct current stimulation over the cerebellum of patients affected by cortical myoclonus and healthy controls and assessed its effect on sensorimotor cortex excitability. We expected that anodal cerebellar transcranial direct current stimulation would increase the inhibitory cerebellar drive to the motor cortex and therefore reduce the sensorimotor cortex hyperexcitability observed in cortical myoclonus. Ten patients affected by cortical myoclonus of various aetiology and 10 aged-matched healthy control subjects were included in the study. All participants underwent somatosensory evoked potentials, long-latency reflexes and short-interval intracortical inhibition recording at baseline and immediately after 20 min session of cerebellar anodal transcranial direct current stimulation. In patients, myoclonus was recorded by the means of surface EMG before and after the cerebellar stimulation. Anodal cerebellar transcranial direct current stimulation did not change the above variables in healthy controls, while it significantly increased the amplitude of somatosensory evoked potential cortical components, long-latency reflexes and decreased short-interval intracortical inhibition in patients; alongside, a trend towards worsening of the myoclonus after the cerebellar stimulation was observed. Interestingly, when dividing patients in those with and without giant somatosensory evoked potentials, the increment of the somatosensory evoked potential cortical components was observed mainly in those with giant potentials. Our data showed that anodal cerebellar transcranial direct current stimulation facilitates-and does not inhibit-sensorimotor cortex excitability in cortical myoclonus syndromes. This paradoxical response might be due to an abnormal homeostatic plasticity within the sensorimotor cortex, driven by dysfunctional cerebello-thalamo-cortical input to the motor cortex. We suggest that the cerebellum is implicated in the pathophysiology of cortical myoclonus and that these results could open the way to new forms of treatment or treatment targets.
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Affiliation(s)
- Anna Latorre
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Lorenzo Rocchi
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
- Department of Medical Sciences and Public Health, University of Cagliari, Cagliari 09042, Italy
| | - Giulia Paparella
- Department of Neurology, IRCCS Neuromed, Pozzilli, IS 86077, Italy
- Department of Human Neurosciences, Sapienza University of Rome, Rome 00185, Italy
| | - Nicoletta Manzo
- Department of Neurology, IRCCS San Camillo Hospital, Venice 30126, Italy
| | - Kailash P Bhatia
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
| | - John C Rothwell
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
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Kim KY, Moon JU, Lee JY, Eom TH, Kim YH, Lee IG. Distributed source localization of epileptiform discharges in juvenile myoclonic epilepsy: Standardized low-resolution brain electromagnetic tomography (sLORETA) Study. Medicine (Baltimore) 2022; 101:e29625. [PMID: 35777062 PMCID: PMC9239631 DOI: 10.1097/md.0000000000029625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Juvenile myoclonic epilepsy (JME) is a common generalized epilepsy syndrome considered the prototype of idiopathic generalized epilepsy. To date, generalized and focal seizures have been the fundamental concepts for classifying seizure types. In several studies, focal features of JME have been reported predominantly in the frontal lobe. However, results in previous studies are inconsistent. Therefore, we investigated the origin of epileptiform discharges in JME. We performed electroencephalography source localization using a distributed model with standardized low-resolution brain electromagnetic tomography. In 20 patients with JME, standardized low-resolution brain electromagnetic tomography images corresponding to the midpoint of the ascending phase and the negative peak of epileptiform discharges were obtained from a total of 362 electroencephalography epochs (181 epochs at each timepoint). At the ascending phase, the maximal current source density was located in the frontal lobe (58.6%), followed by the parietal (26.5%) and occipital lobes (8.8%). At the negative peak, the maximal current source density was located in the frontal lobe (69.1%), followed by the parietal (11.6%) and occipital lobes (9.4%). In the ascending phase, 41.4% of discharges were located outside the frontal lobe, and 30.9% were in the negative peak. Frontal predominance of epileptiform discharges was observed; however, source localization extending to various cortical regions also was identified. This widespread pattern was more prominent in the ascending phase (P = .038). The study results showed that JME includes widespread cortical regions over the frontal lobe. The current concept of generalized epilepsy and pathophysiology in JME needs further validation.
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Affiliation(s)
- Kwang Yeon Kim
- Department of Pediatrics, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Ja-Un Moon
- Department of Pediatrics, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Joo-Young Lee
- Department of Pediatrics, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Tae-Hoon Eom
- Department of Pediatrics, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Young-Hoon Kim
- Department of Pediatrics, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - In-Goo Lee
- Department of Pediatrics, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
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Moon JU, Lee JY, Kim KY, Eom TH, Kim YH, Lee IG. Comparative analysis of background EEG activity in juvenile myoclonic epilepsy during valproic acid treatment: a standardized, low-resolution, brain electromagnetic tomography (sLORETA) study. BMC Neurol 2022; 22:48. [PMID: 35139806 PMCID: PMC8827290 DOI: 10.1186/s12883-022-02577-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 01/31/2022] [Indexed: 11/11/2022] Open
Abstract
Background By definition, the background EEG is normal in juvenile myoclonic epilepsy (JME) patients and not accompanied by other developmental and cognitive problems. However, some recent studies using quantitative EEG (qEEG) reported abnormal changes in the background activity. QEEG investigation in patients undergoing anticonvulsant treatment might be a useful approach to explore the electrophysiology and anticonvulsant effects in JME. Methods We investigated background EEG activity changes in patients undergoing valproic acid (VPA) treatment using qEEG analysis in a distributed source model. In 17 children with JME, non-parametric statistical analysis using standardized low-resolution brain electromagnetic tomography was performed to compare the current density distribution of four frequency bands (delta, theta, alpha, and beta) between untreated and treated conditions. Results VPA reduced background EEG activity in the low-frequency (delta-theta) bands across the frontal, parieto-occipital, and limbic lobes (threshold log-F-ratio = ±1.414, p < 0.05; threshold log-F-ratio= ±1.465, p < 0.01). In the delta band, comparative analysis revealed significant current density differences in the occipital, parietal, and limbic lobes. In the theta band, the analysis revealed significant differences in the frontal, occipital, and limbic lobes. The maximal difference was found in the delta band in the cuneus of the left occipital lobe (log-F-ratio = −1.840) and the theta band in the medial frontal gyrus of the left frontal lobe (log-F-ratio = −1.610). Conclusions This study demonstrated the anticonvulsant effects on the neural networks involved in JME. In addition, these findings suggested the focal features and the possibility of functional deficits in patients with JME.
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Affiliation(s)
- Ja-Un Moon
- Department of Pediatrics, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Joo-Young Lee
- Department of Pediatrics, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Kwang-Yeon Kim
- Department of Pediatrics, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Tae-Hoon Eom
- Department of Pediatrics, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.
| | - Young-Hoon Kim
- Department of Pediatrics, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - In-Goo Lee
- Department of Pediatrics, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
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Fustes OJH, Kay CSK, Lorenzoni PJ, Ducci RDP, Werneck LC, Scola RH. Somatosensory evoked potentials in clinical practice: a review. ARQUIVOS DE NEURO-PSIQUIATRIA 2021; 79:824-831. [PMID: 34669817 DOI: 10.1590/0004-282x-anp-2020-0427] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 12/28/2020] [Indexed: 11/22/2022]
Abstract
The authors present a review of the current use of somatosensory evoked potentials (SSEPs) in neurological practice as a non-invasive neurophysiological technique. For this purpose we have reviewed articles published in English or Portuguese in the PubMed and LILACS databases. In this review, we address the role of SSEPs in neurological diseases that affect the central nervous system and the peripheral nervous system, especially in demyelinating diseases, for monitoring coma, trauma and the functioning of sensory pathways during surgical procedures. The latter, along with new areas of research, has become one of the most important applications of SSEPs.
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Affiliation(s)
- Otto Jesus Hernández Fustes
- Universidade Federal do Paraná, Complexo Hospital de Clínicas, Departamento de Clínica Médica, Serviço de Neurologia, Serviço de Doenças Neuromusculares e Desmielinizantes, Curitiba PR, Brazil
| | - Cláudia Suemi Kamoi Kay
- Universidade Federal do Paraná, Complexo Hospital de Clínicas, Departamento de Clínica Médica, Serviço de Neurologia, Serviço de Doenças Neuromusculares e Desmielinizantes, Curitiba PR, Brazil
| | - Paulo José Lorenzoni
- Universidade Federal do Paraná, Complexo Hospital de Clínicas, Departamento de Clínica Médica, Serviço de Neurologia, Serviço de Doenças Neuromusculares e Desmielinizantes, Curitiba PR, Brazil
| | - Renata Dal-Prá Ducci
- Universidade Federal do Paraná, Complexo Hospital de Clínicas, Departamento de Clínica Médica, Serviço de Neurologia, Serviço de Doenças Neuromusculares e Desmielinizantes, Curitiba PR, Brazil
| | - Lineu Cesar Werneck
- Universidade Federal do Paraná, Complexo Hospital de Clínicas, Departamento de Clínica Médica, Serviço de Neurologia, Serviço de Doenças Neuromusculares e Desmielinizantes, Curitiba PR, Brazil
| | - Rosana Herminia Scola
- Universidade Federal do Paraná, Complexo Hospital de Clínicas, Departamento de Clínica Médica, Serviço de Neurologia, Serviço de Doenças Neuromusculares e Desmielinizantes, Curitiba PR, Brazil
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Kızıltan ME, Yeni SN, Aliş C, Gündüz A. Recovery function of somatosensory evoked potentials in juvenile myoclonic epilepsy*. Somatosens Mot Res 2019; 36:195-201. [DOI: 10.1080/08990220.2019.1644999] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Meral E. Kızıltan
- Department of Neurology, Cerrahpasa Medical Faculty, I.U.C., Istanbul, Turkey
| | - S. Naz Yeni
- Department of Neurology, Cerrahpasa Medical Faculty, I.U.C., Istanbul, Turkey
| | - Ceren Aliş
- Department of Neurology, Cerrahpasa Medical Faculty, I.U.C., Istanbul, Turkey
| | - Ayşegül Gündüz
- Department of Neurology, Cerrahpasa Medical Faculty, I.U.C., Istanbul, Turkey
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