Corticospinal disinhibition in paroxysmal kinesigenic dyskinesia.
OBJECTIVE
To investigate the underlying mechanism responsible for paroxysmal kinesigenic dyskinesia (PKD).


METHODS
We performed a transcranial magnetic stimulation (TMS) study in 12 drug-naïve patients with PKD and 10 healthy volunteers. TMS parameters included resting motor threshold, recruitment curve of motor evoked potential amplitudes, short intracortical inhibition and facilitation, long intracortical inhibition (LICI), and silent period. We also measured compound muscle action potential.


RESULTS
LICI, representing GABA-mediated inhibition, was significantly reduced in the patients (P = 0.033), while results for all other TMS parameters tested were comparable between the two groups.


CONCLUSIONS
These results suggest that a specific type of corticospinal inhibitory mechanism is impaired in patients with PKD.
Kang
S Y
SY
Department of Neurology and Brain Research Institute, Yonsei University College of Medicine, 134 Shinchon-dong, Seodaemun-ku, Seoul, South Korea.
Sohn
Y H
YH
Kim
H S
HS
Lyoo
C H
CH
Lee
M S
MS
D000200:Action Potentials / Q000502:physiology / Q000528:radiation effects; D000328:Adult; D000704:Analysis of Variance; D002819:Chorea / Q000503:physiopathology*; D004576:Electromyography / Q000379:methods; D019054:Evoked Potentials, Motor / Q000502:physiology / Q000528:radiation effects; D005260:Female; D006801:Humans; D008297:Male; D009433:Neural Inhibition / Q000502:physiology* / Q000528:radiation effects; D011712:Pyramidal Tracts / Q000503:physiopathology* / Q000528:radiation effects; D011930:Reaction Time / Q000502:physiology / Q000528:radiation effects; D013997:Time Factors; D050781:Transcranial Magnetic Stimulation / Q000379:methods