Movement dysfunction in patients with Parkinson's disease: A literature review

Experimental evidence has shown that people with Parkinson's disease have deficits in the initiation and execution of movements. The delay in response initiation may be due to impairment in the organisation or translation of motor programs into muscle actions. The slowness in the execution of simple movements may result from inappropriate scaling of muscle activity, defective predictive function or defective memory for the computed forces. Extra slowness in the execution of complicated concurrent movements appears to be a result of deficits in switching from one program to another within a motor plan in sequential movements, or in superimposition of motor programs to form a motor plan in simultaneous movements.