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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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Cuccurullo C, Striano P, Coppola A. Familial Adult Myoclonus Epilepsy: A Non-Coding Repeat Expansion Disorder of Cerebellar-Thalamic-Cortical Loop. Cells 2023; 12:1617. [PMID: 37371086 DOI: 10.3390/cells12121617] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 06/07/2023] [Accepted: 06/09/2023] [Indexed: 06/29/2023] Open
Abstract
Familial adult myoclonus Epilepsy (FAME) is a non-coding repeat expansion disorder that has been reported under different acronyms and initially linked to four main loci: FAME1 (8q23.3-q24.1), FAME 2 (2p11.1-q12.1), FAME3 (5p15.31-p15.1), and FAME4 (3q26.32-3q28). To date, it is known that the genetic mechanism underlying FAME consists of the expansion of similar non-coding pentanucleotide repeats, TTTCA and TTTTA, in different genes. FAME is characterized by cortical tremor and myoclonus usually manifesting within the second decade of life, and infrequent seizures by the third or fourth decade. Cortical tremor is the core feature of FAME and is considered part of a spectrum of cortical myoclonus. Neurophysiological investigations as jerk-locked back averaging (JLBA) and corticomuscular coherence analysis, giant somatosensory evoked potentials (SEPs), and the presence of long-latency reflex I (or C reflex) at rest support cortical tremor as the result of the sensorimotor cortex hyperexcitability. Furthermore, the application of transcranial magnetic stimulation (TMS) protocols in FAME patients has recently shown that inhibitory circuits are also altered within the primary somatosensory cortex and the concomitant involvement of subcortical networks. Moreover, neuroimaging studies and postmortem autoptic studies indicate cerebellar alterations and abnormal functional connectivity between the cerebellum and cerebrum in FAME. Accordingly, the pathophysiological mechanism underlying FAME has been hypothesized to reside in decreased sensorimotor cortical inhibition through dysfunction of the cerebellar-thalamic-cortical loop, secondary to primary cerebellar pathology. In this context, the non-coding pentameric expansions have been proposed to cause cerebellar damage through an RNA-mediated toxicity mechanism. The elucidation of the underlying pathological mechanisms of FAME paves the way to novel therapeutic possibilities, such as RNA-targeting treatments, possibly applicable to other neurodegenerative non-coding disorders.
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Affiliation(s)
- Claudia Cuccurullo
- Department of Neuroscience, Reproductive Sciences and Odontostomatology, Federico II University of Naples, 80131 Naples, Italy
| | - Pasquale Striano
- Pediatric Neurology and Muscular Diseases Unit, IRCCS Istituto Giannina Gaslini, 16147 Genova, Italy
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova, 16126 Genova, Italy
| | - Antonietta Coppola
- Department of Neuroscience, Reproductive Sciences and Odontostomatology, Federico II University of Naples, 80131 Naples, Italy
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Abstract
Myoclonus can cause significant disability for patients. Myoclonus has a strikingly diverse array of underlying etiologies, clinical presentations, and pathophysiological mechanisms. Treatment of myoclonus is vital to improving the quality of life of patients with these disorders. The optimal treatment strategy for myoclonus is best determined based upon careful evaluation and consideration of the underlying etiology and neurophysiological classification. Electrophysiological testing including EEG (electroencephalogram) and EMG (electromyogram) data is helpful in determining the neurophysiological classification of myoclonus. The neurophysiological subtypes of myoclonus include cortical, cortical-subcortical, subcortical-nonsegmental, segmental, and peripheral. Levetiracetam, valproic acid, and clonazepam are often used to treat cortical myoclonus. In cortical-subcortical myoclonus, treatment of myoclonic seizures is prioritized, valproic acid being the mainstay of therapy. Subcortical-nonsegmental myoclonus may be treated with clonazepam, though numerous agents have been used depending on the etiology. Segmental and peripheral myoclonus are often resistant to treatment, but anticonvulsants and botulinum toxin injections may be of utility depending upon the case. Pharmacological treatments are often hampered by scarce evidence-based knowledge, adverse effects, and variable efficacy of medications.
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Affiliation(s)
- Ashley B. Pena
- Department of Neurology, Mayo Clinic Florida, 4500 San Pablo Rd S, Jacksonville, Florida 32224 USA
| | - John N. Caviness
- Department of Neurology, Mayo Clinic Arizona, 13400 East Shea Blvd., Scottsdale, Arizona 85259 USA
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Nardone R, Versace V, Höller Y, Sebastianelli L, Brigo F, Lochner P, Golaszewski S, Saltuari L, Trinka E. Transcranial magnetic stimulation in myoclonus of different aetiologies. Brain Res Bull 2018; 140:258-269. [DOI: 10.1016/j.brainresbull.2018.05.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Revised: 05/12/2018] [Accepted: 05/18/2018] [Indexed: 12/29/2022]
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Rossi Sebastiano D, Magaudda A, Quartarone A, Brizzi T, Visani E, Capovilla G, Beccaria F, Anversa P, Franceschetti S, Canafoglia L. Effect of repetitive transcranial magnetic stimulation on action myoclonus: A pilot study in patients with EPM1. Epilepsy Behav 2018; 80:33-36. [PMID: 29396360 DOI: 10.1016/j.yebeh.2017.11.031] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 10/13/2017] [Accepted: 11/26/2017] [Indexed: 11/24/2022]
Abstract
OBJECTIVE The objective of this study was to explore the short-term effects of repetitive transcranial magnetic stimulation (rTMS) on action myoclonus. METHODS Nine patients with Unverricht-Lundborg (EPM1) progressive myoclonus epilepsy type underwent two series of 500 stimuli at 0.3Hz through round coil twice a day for five consecutive days. Clinical and neurophysiological examinations were performed two hours before starting the first rTMS session and two hours after the end of the last rTMS session. RESULTS Eight patients completed the protocol; one discontinued because of a transient increase in spontaneous jerks. The unified myoclonus rating scale indicated a 25% reduction in posttreatment myoclonus with action score associated with an increase in the cortical motor threshold and lengthening of the cortical silent period (CSP). The decrease in the myoclonus with action scores correlated with the prolongation of CSP. CONCLUSIONS Repetitive transcranial magnetic stimulation can be safely used in patients with EPM1, improves action myoclonus, and partially restores deficient cortical inhibition.
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Affiliation(s)
- Davide Rossi Sebastiano
- Neurophysiopathology and Epilepsy Centre Unit, IRCCS Foundation Carlo Besta Neurological Institute, Milan, Italy
| | | | - Angelo Quartarone
- Department of Biomedical, Dental Sciences and Morphological and Functional Images, University of Messina, Messina, Italy; IRCCS Centro Neurolesi 'Bonino Pulejo', Messina, Italy
| | - Teresa Brizzi
- Epilepsy Centre, University of Messina, Messina, Italy
| | - Elisa Visani
- Neurophysiopathology and Epilepsy Centre Unit, IRCCS Foundation Carlo Besta Neurological Institute, Milan, Italy
| | - Giuseppe Capovilla
- Epilepsy Centre, Department of Child Neuropsychiatry, C. Poma Hospital, Mantua, Italy
| | - Francesca Beccaria
- Epilepsy Centre, Department of Child Neuropsychiatry, C. Poma Hospital, Mantua, Italy
| | - Paola Anversa
- Neurophysiopathology and Epilepsy Centre Unit, IRCCS Foundation Carlo Besta Neurological Institute, Milan, Italy
| | - Silvana Franceschetti
- Neurophysiopathology and Epilepsy Centre Unit, IRCCS Foundation Carlo Besta Neurological Institute, Milan, Italy
| | - Laura Canafoglia
- Neurophysiopathology and Epilepsy Centre Unit, IRCCS Foundation Carlo Besta Neurological Institute, Milan, Italy.
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Wischnewski M, Schutter DJ. After-effects of transcranial alternating current stimulation on evoked delta and theta power. Clin Neurophysiol 2017; 128:2227-2232. [DOI: 10.1016/j.clinph.2017.08.029] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Revised: 07/06/2017] [Accepted: 08/24/2017] [Indexed: 11/28/2022]
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Rogasch NC, Todd G. rTMS over human motor cortex can modulate tremor during movement. Eur J Neurosci 2012; 37:323-9. [PMID: 23106333 DOI: 10.1111/ejn.12023] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2012] [Accepted: 09/14/2012] [Indexed: 11/30/2022]
Abstract
Abnormally large tremor during movement is a symptom of many movement disorders and significantly impairs activities of daily living. The aim of this study was to investigate whether repetitive magnetic brain stimulation (rTMS) can reduce tremor size during human movement. We hypothesised that inhibitory rTMS over motor cortex would reduce tremor size during subsequent movement. The study involved 26 healthy young adults (21 ± 2 years) and began with application of single TMS stimuli to measure baseline corticospinal excitability. The response to stimulation was recorded in hand muscles with electromyography. Subjects then performed a 3-min task to measure baseline tremor during movement. This involved matching index finger position with a moving target on a computer screen. Tremor was recorded with an accelerometer on the fingernail. Finger acceleration was analysed with fast-Fourier transform to quantify tremor in the physiological range (7.8-12.2 Hz). Subjects then received 10 min of real (n = 13) or sham (n = 13) inhibitory rTMS. Tremor and corticospinal excitability were then remeasured. Real rTMS significantly decreased corticospinal excitability by ~30% (P = 0.022) and increased tremor size during movement by ~120% (P = 0.047) relative to sham rTMS. However, the direction of tremor change was opposite to that hypothesised for inhibitory rTMS. The results suggest that rTMS over human motor cortex can modulate action tremor and the level of corticospinal excitability may be important for setting the amplitude of action tremor in healthy young adults.
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Affiliation(s)
- Nigel C Rogasch
- Monash Alfred Psychiatry Research Centre, Alfred and Monash University Central Clinical School, Monash University, Melbourne, Vic, Australia
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Movement preparation and cortical processing of afferent inputs in cortical tremor: An event-related (de)synchronization (ERD/ERS) study. Clin Neurophysiol 2012; 123:1207-15. [DOI: 10.1016/j.clinph.2011.10.043] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2011] [Revised: 10/17/2011] [Accepted: 10/29/2011] [Indexed: 11/22/2022]
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Clinical applications of transcranial magnetic stimulation in patients with movement disorders. Lancet Neurol 2008; 7:827-40. [DOI: 10.1016/s1474-4422(08)70190-x] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Oulad Ben Taib N, Manto M. Effects of trains of high-frequency stimulation of the premotor/supplementary motor area on conditioned corticomotor responses in hemicerebellectomized rats. Exp Neurol 2008; 212:157-65. [PMID: 18482725 DOI: 10.1016/j.expneurol.2008.03.016] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2007] [Revised: 03/06/2008] [Accepted: 03/18/2008] [Indexed: 01/30/2023]
Abstract
We studied the effects of low- and high-frequency premotor electrical stimulations on conditioned corticomotor responses, intra-cortical facilitation (ICF) and spinal excitability in hemicerebellectomized rats (left side). Trains of stimulation were applied in prefrontal region rFr2 (the equivalent of the premotor/supplementary motor area in primates) at a rate of 1 Hz (low-frequency stimulation LFS) or 20 Hz (high-frequency stimulation HFS). Test stimuli on the motor cortex were preceded by a conditioning stimulus in contralateral sciatic nerve (two inter-stimulus intervals ISIs were studied: 5 ms or 45 ms). (A) At ISI-5, conditioning increased amplitudes of MEPs (motor evoked potentials) in the left motor cortex. This afferent facilitation was enhanced if preceded by trains of stimuli administered over the ipsilateral rFr2 area, and HFS had higher effects than LFS. The facilitation was lower for the right motor cortex, for both LFS and HFS. (B) At ISI-45, conditioned motor evoked responses were depressed as compared to unconditioned responses in the left motor cortex (afferent inhibition). Following LFS, the degree of inhibition was unchanged while it increased with HFS. At baseline, inhibition was enhanced in the right motor cortex. Interestingly, the afferent inhibition decreased significantly following HFS. (C) ICF was depressed in the right motor cortex, but increased similarly on both sides following LFS/HFS. These results (1) confirm the increased inhibition in the motor cortex contralaterally to the hemicerebellar ablation, (2) demonstrate for the first time that the cerebellum is necessary for tuning amplitudes of corticomotor responses following a peripheral nerve stimulation, (3) show that the application of LFS or HFS does not cancel the defect of excitability in the motor cortex for short ISIs, and (4) suggest that for longer ISIs, HFS could have interesting properties for the modulation of afferent inhibition in case of extensive cerebellar lesion. Our study underlines that cerebellar ablation impacts on the efficacy of combined peripheral-motor cortex stimulation in an ISI-dependent manner.
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The effects of low- and high-frequency repetitive TMS on the input/output properties of the human corticospinal pathway. Exp Brain Res 2008; 187:207-17. [DOI: 10.1007/s00221-008-1294-z] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2007] [Accepted: 01/19/2008] [Indexed: 10/22/2022]
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