Hypokinesia and bradykinesia in Parkinson’s disease are consistent with reduced motor vigour, not an impaired capacity to generate and transmit neural drive to muscle

Hypokinesia and bradykinesia in Parkinson’s disease have been attributed to reduced motor vigour, an account that assumes the neural drive to muscle is intact but inappropriately scaled; an alternative is that generation of the drive is itself impaired. We recorded high-density surface EMG in 12 peo