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Impaired motor imagery in patients with essential tremor: A case control study
Author(s) -
Lo YewLong,
Louis Elan D.,
FookChong Stephanie,
Tan EngKing
Publication year - 2007
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.21356
Subject(s) - transcranial magnetic stimulation , essential tremor , motor imagery , psychology , stimulation , analysis of variance , evoked potential , cerebellum , motor control , audiology , neuroscience , physical medicine and rehabilitation , electrophysiology , medicine , electroencephalography , brain–computer interface
Motor imagery (MI), which refers to the process of mental representation of movements, has not been studied in patients with essential tremor (ET). We investigated the presence of impaired MI in ET patients compared with healthy controls. A group of drug‐naive and nondemented ET patients and age‐matched controls were studied using transcranial magnetic stimulation, while they were specifically instructed to try and imagine themselves performing two motor tasks. The various clinical and electrophysiological variables were evaluated and compared. Repeated measures ANOVA demonstrated a significant difference between ET patients and controls with respect to mean motor‐evoked potential (MEP) amplitudes ( F (1,38) = 31.92, P < 0.005) during MI. The process of MI effectively facilitated MEP amplitude in controls but not in ET patients, regardless of side of stimulation or motor tasks. We provide evidence to demonstrate impairment of MI in a group of ET patients compared with healthy controls. The basis for this novel finding is unclear, and further studies are warranted to determine whether it is related to cerebellar or motor cortical dysfunction. © 2007 Movement Disorder Society