The biomechanics and motor control of gait in Parkinson disease

Parkinson disease is a progressive neurological condition characterised by hypokinesia (reduced movement). akinesia (absent movement), tremor, rigidit y and postural instability. These movement disorders are associated with a slow short-stepped, shuffling gait pattern. Analysis of the biomechanics of gait in response to medication, visual cues. attentional strategies and ne urosurgery provides insight into the nature of the motor control deficit in Parkinson disease and the efficacy of current therapeutic interventions. I n this article we supplement a critical evaluation of the Parkinson disease gait literature with two case examples. The first case describes the kinem atic gait response of an individual with Parkinson disease to visual cues i n the "off" phase of the levodopa medication cycle. The second case investi gates the biomechanics and motor control of turning during walking in a pat ient with Parkinson disease compared with elderly and young control subject s. The results are interpreted in light of the need for gait analysis to in vestigate complex functional walking tasks rather than confining assessment to straight line walking, which has been the trend to date. (C) 2001 Elsev ier Science Ltd. All rights reserved.