VOLUNTARY AND INVOLUNTARY ADAPTATION OF GAIT IN PARKINSONS-DISEASE

Voluntary and involuntary adaptation of gait in Parkinson's disease (P D) were studied in two separate experiments. In the first experiment, effects of changes in voluntary control were studied by asking PD pati ents and age-matched healthy subjects to adapt their walking pattern t o visual cues resulting in spatial constraints, and auditory cues resu lting in temporal constraints on stepping movements. In the second exp eriment, the adaptation to increases in speed during overground and tr eadmill walking was studied. Most patients were able to adapt their wa lking patterns in accordance with instructions. Notwithstanding consis tent differences in step length, the adaptation to different condition s under study was highly similar in PD patients and healthy subjects. Only during walking with visually guided step length were the observed adaptations in PD patients less consistent. Contrary to these dissimi larities, the involuntary adaptation of timing of support and swing ph ases within the stride cycle was very similar between groups. In all c onditions, only with changes in step length could a change in relative timing be observed. Our findings show that voluntary adaptation of ga it is possible in PD and that basic involuntary coordination mechanism s are preserved. The observed disturbances in stride length regulation probably reflect an inability to perform fast movements in PD. (C) 19 98 Elsevier Science B.V.