Objectives: To study the deficit of inhibition of excessive motor drive gen
erated in the central nervous system in chorea.
Methods: Identical associated movements in the contralateral limb elicited
by rapid hand squeezing were measured in 6 patients with Huntington's disea
se, 7 patients with peak-dose dyskinesia, 10 patients with Parkinson's dise
ase, 8 patients with spinocerebellar degeneration and in 8 normal subjects.
The intensity of associated movements was assessed by the EMG amplitude ra
tio of associated contractions to active contractions.
Results: The associated movement ratios were larger in Huntington's disease
and peak-dose dyskinesia as compared to other groups. The ratios in akinet
ic 'off' phase were smaller than those in dyskinetic 'on' phase in all peak
-dose dyskinesia patients.
Conclusions: Enhanced associated movements support a possible common mechan
ism that chorea may result from failure in inhibition of phasic neural acti
vity pathologically generated in the brain. (C) 2001 Elsevier Science Irela
nd Ltd. All rights reserved.