The effect of directing attention during walking under dual-task conditions in Parkinson's disease.

The aim of this study was to investigate the effect of directing attention on walking performance under dual-task conditions in people with Parkinson's disease (PD). Twelve subjects with mild to moderate PD were tested 'on' medication. Subjects walked at comfortable speed under 2 baseline conditions: (i) walking with hands-free, no specific instructions and (ii) walking carrying a tray and glasses, no specific instructions; and 2 experimental conditions: (i) walking carrying a tray and glasses with instructions to direct attention towards walking and (ii) walking carrying a tray and glasses with instructions to direct attention towards the tray and glasses. When instructed to direct their attention towards walking while carrying the tray and glasses, subjects walked faster (P=0.003) and with longer strides (P<0.001) than when they were given no specific instructions. These improvements in walking were achieved without any significant adverse effect on carrying the tray of glasses. The improvement obtained was to a level comparable to that achieved when subjects walked with their hands-free. This suggests that specific instructions can be used to manipulate attention to enhance the performance of everyday dual-tasks in people with mild to moderate PD.