A component analysis of the generation and release of isometric force in Parkinson's disease.
Paradigms of isometric force control allow study of the generation and release of movement in the absence of complications due to disordered visuomotor coordination. The onset and release of isometric force in Parkinson's disease (PD) was studied, using computerised determinants of latency of response and rate of force generation and release. Components of isometric force control were related to measures of cognitive, affective and clinical motor disability. The effects of treatment were determined by longitudinal study of de novo patients. Patients with PD showed impairment in latency and rate of force change for movement release as well as onset. Rate of force change correlated with depression, clinical motor disability and memory quotient but latency showed no correlation with any of these measures. Treatment improved rate of force release, in concert with clinical motor disability, but not latency. These results suggest dissociations between latency and rate of force change that may be linked to different neurochemical deficits. Further, they demonstrate akinetic deficits in force release that argue against the "neural energy hypothesis" of akinesia.
Jordan
N
N
Department of Neurology, Royal Hallamshire Hospital, Sheffield, UK.
Sagar
H J
HJ
Cooper
J A
JA
D001971:Bromocriptine / Q000008:administration & dosage; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D007537:Isometric Contraction / Q000187:drug effects / Q000502:physiology*; D007980:Levodopa / Q000008:administration & dosage; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009046:Motor Neurons / Q000187:drug effects / Q000502:physiology; D009132:Muscles / Q000294:innervation; D009460:Neurologic Examination / Q000187:drug effects; D010300:Parkinson Disease / Q000175:diagnosis / Q000188:drug therapy / Q000503:physiopathology*; D011930:Reaction Time / Q000187:drug effects; D014282:Trihexyphenidyl / Q000008:administration & dosage
D001971:Bromocriptine; D007980:Levodopa; D014282:Trihexyphenidyl