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Involvement of the motor cortex in pseudochoreoathetosis
Author(s) -
Timmermann Lars,
Gross Joachim,
Schmitz Frank,
Freund HansJoachim,
Schnitzler Alfons
Publication year - 2001
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.1180
Subject(s) - magnetoencephalography , motor cortex , coherence (philosophical gambling strategy) , electromyography , neuroscience , physical medicine and rehabilitation , supplementary motor area , psychology , forearm , cortex (anatomy) , medicine , electroencephalography , audiology , anatomy , functional magnetic resonance imaging , physics , stimulation , quantum mechanics
The pathophysiological background of involuntary movements in pseudochoreoathetosis is unclear. We therefore recorded in four patients with pseudochoreoathetosis and in six age‐matched controls cortical activity with a whole‐head magnetoencephalography (MEG) system and surface EMGs from hand muscles. Subjects performed the following tasks: 1) rest, and 2) constant finger stretch during forearm elevation; controls additionally simulated pseudochoreoathetotic finger movements. During rest, the patients showed involuntary finger movements associated with excessive MEG‐EMG coherence at frequencies between 6 and 20 Hz, whereas coherence in controls simulating pseudochoreoathetotic movements did not exceed noise level ( P < 0.02). During finger stretch, MEG‐EMG coherence in patients was similar to that of controls. Cortical sources of MEG‐EMG coherence in patients were localized in the contralateral motor cortex. We conclude that pseudochoreoathetosis is associated with pathologically increased corticomuscular coherence and thus differs, neurophysiologically, from voluntarily simulated pseudochoreoathetotic movements. The enhanced MEG‐EMG coherence in pseudochoreoathetosis probably reflects a pathologically strong motor cortical drive of spinal motorneurons after deafferentation. © 2001 Movement Disorder Society.