Spontaneously Fluctuating Motor Cortex Excitability in Alternating Hemiplegia of Childhood: A Transcranial Magnetic Stimulation Study

Authors:

Stern WM; Desikan M; Hoad D; Jaffer F; Strigaro G; Sander JW; Rothwell JC; Sisodiya SM. Institution Stern,William M. NIHR University College London Hospitals Biomed ical Research Centre, Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London, WC1N 3BG, United Kingdom. Stern,William M. Epilepsy Society, Chalfont St Peter, SL9 0RJ, Unit ed Kingdom. Desikan,Mahalekshmi. Sobell Department of Motor Neuroscience and Mo vement Disorders, UCL Institute of Neurology, London, United King dom. Hoad,Damon. Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, London, United King dom. Jaffer,Fatima. MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology, London, WC1N 3BG, United Kingdom. Strigaro,Gionata. Department of Translational Medicine, Section of Neurology, University of Piemonte Orientale “A. Avogadro”, Novara, I taly. Sander,Josemir W. NIHR University College London Hospitals Biomedi cal Research Centre, Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London, WC1N 3BG, United Kingdom. Sander,Josemir W. Epilepsy Society, Chalfont St Peter, SL9 0RJ, Uni ted Kingdom. Sander,Josemir W. Stichting Epilepsie Instellingen Nederland (SEIN ), Heemstede, Netherlands. Rothwell,John C. Sobell Department of Motor Neuroscience and Mov ement Disorders, UCL Institute of Neurology, London, United King dom. Sisodiya,Sanjay M. NIHR University College London Hospitals Biomedic al Research Centre, Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London, WC1N 3BG, United Kingdom. Sisodiya,Sanjay M. Epilepsy Society, Chalfont St Peter, SL9 0RJ, Uni ted Kingdom.

Title:

Spontaneously Fluctuating Motor Cortex Excitability in Alternating Hemiplegia of Childhood: A Transcranial Magnetic Stimulation Study.

Source:

PLoS ONE [Electronic Resource]. 11(3):e0151667, 2016.

Abstract

BACKGROUND: Alternating hemiplegia of childhood is a very rare a nd serious neurodevelopmental syndrome; its genetic basis has recently been established. Its characteristic features include typically-unp rovoked episodes of hemiplegia and other transient or more persisten t neurological abnormalities.

METHODS: We used transcranial magnetic stimulation to assess the eff ect of the condition on motor cortex neurophysiology both dur ing and between attacks of hemiplegia. Nine people with alternating hemiplegia of childhood were recruited; eight were successfully tested usi ng transcranial magnetic stimulation to study motor cortex excitab ility, using single and paired pulse paradigms. For comparison, data from ten people with epilepsy but not alternating hemiplegia, and ten h ealthy controls, were used.

RESULTS: One person with alternating hemiplegia tested during th e onset of a hemiplegic attack showed progressively diminishing motor co rtex excitability until no response could be evoked; a second pers on tested during a prolonged bilateral hemiplegic attack showed unusuall y low excitability. Three people tested between attacks showed asymptomati c variation in cortical excitability, not seen in controls . Paired pulse paradigms, which probe intracortical inhibitory and excitat ory circuits, gave results similar to controls.

CONCLUSIONS: We report symptomatic and asymptomatic fluctuations in motor cortex excitability in people with alternating hemiplegia of childhood, not seen in controls. We propose that such fluctuations underlie hemiplegic attacks, and speculate that the asymptomatic fluctuation we detected may be useful as a biomarker for disease activity.

Publication Type Journal Article. Research Support, Non-U.S. Gov’t.