Delayed motor response correlates with striatal degeneration in Parkinson's disease

Objective - Studies on reaction time have suggested a selective deficit of slowness in motor readiness and motor programming in Parkinson's disease (P D). Objective of this study was the putative relation between delayed initi ation and execution of movement and the striatal dopamine deficiency in PD. Material and methods - We investigated 32 idiopathic, previously untreated parkinsonian patients to evaluate dopaminergic nigrostriatal degeneration by single photon emission tomography in combination with the radiotracer [I -123]-beta-CIT and performed a simple reaction time paradigm on the same da y. Results - Significant relations between the [I-123]-beta-CIT-SPECT-ratio striatum/cerebellum and reaction - and movement time appeared. Reaction ti me and movement time of parkinsonian patients were significantly longer com pared to age-matched controls. Conclusions - We conclude that reaction- and movement-time is related to the dopaminergic nigrostriatal degeneration in untreated parkinsonian subjects.