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Cerebellar stimulation fails to modulate motor cortex plasticity in writing dystonia
Author(s) -
Sadnicka Anna,
Hamada Masashi,
Bhatia Kailash P.,
Rothwell John C.,
Edwards Mark J.
Publication year - 2014
Publication title -
movement disorders
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.352
H-Index - 198
eISSN - 1531-8257
pISSN - 0885-3185
DOI - 10.1002/mds.25881
Subject(s) - dystonia , stimulation , neuroscience , neuroplasticity , psychology , transcranial direct current stimulation , cerebellum , motor cortex , deep brain stimulation , medicine , parkinson's disease , disease
ABSTRACT Background Primary dystonia is characterized neurophysiologically by reduced inhibitory mechanisms and abnormal regulation of plasticity responses. The potential of anodal cerebellar transcranial direct current stimulation as a therapeutic tool in writing dystonia was examined, after the observation that cerebellar stimulation reduces responses to an associative plasticity protocol in healthy subjects. Methods Ten patients with writing dystonia completed a two‐part study (sham and anodal) in which cerebellar stimulation was given simultaneously with paired associative stimulation. Electrophysiological and clinical parameters were measured before and after stimulation. Results Clinical symptoms were unchanged by cerebellar stimulation. Patients exhibited much variability in the size and direction of their plasticity responses. Excessive or topographically abnormal plasticity responses were not observed. In the subgroup of patients with facilitatory responses to paired associative stimulation in the sham condition, anodal cerebellar stimulation retained its ability to reduce the magnitude of plasticity response. Conclusions Our limited understanding of intersubject variability of plasticity responses in writing dystonia currently undermines cerebellar stimulation as a novel treatment in this subset of dystonia. Cerebellar stimulation may be beneficial in other neurological disorders with consistently exaggerated plasticity. © 2014 International Parkinson and Movement Disorder Society