External Focus Instructions Reduce Postural Instability in Individuals With Parkinson Disease

Abstract

Postural instability while standing, walking, and interacting with objects or the environment places individuals with Parkinson disease (PD) at risk for falls, injuries, and self-imposed restrictions in activity. Recent research with motor skills, including those demanding postural stability, has demonstrated performance and learning advantages when performers are instructed to adopt an external rather than an internal focus of attention. Despite the potential benefits in stability-related risk reduction and enhanced movement effectiveness, attentional focus research in individuals challenged with postural instability is limited. The present translational research study examined the generalizability of the attentional focus effect to balance in older adults with PD. A within-participant design was used to account for potentially substantial individual variations in balancing capabilities. Fourteen participants diagnosed with idiopathic PD (Hoehn and Yahr stages II and III) participated in the experiment. They were asked to balance on an unstable surface (inflated rubber disk). In counterbalanced orders, they were instructed to focus on reducing movements of their feet (internal focus) or the disk (external focus), or they were not given attentional focus instructions (control). The adoption of an external focus resulted in less postural sway relative to both internal focus and control conditions. There was no difference between the internal focus and control conditions. Mental functioning was not formally assessed, and comprehensive clinical profiles of participants were not obtained. The results are consistent with previous findings on attentional focus in samples of patients and people without disabilities. Subtle wording distinctions that direct attention to movement effects external to the mover reduce postural instability during standing for individuals with PD relative to an internal focus. The findings have potentially important implications for instructions given by clinicians and the reduction of fall risk.