Affiliations: [a] School of Rehabilitation and Communication Sciences, Idaho State University, Meridian, ID, USA
| [b]
University of North Texas Health Science Center, Fort Worth, TX, USA
| [c]
University of the Pacific, Sacramento, CA, USA
Correspondence:
[*]
Address for correspondence: Evan V. Papa, PT, DPT, PhD, School of Rehabilitation and Communication Sciences, Idaho State University, Meridian, ID, USA. E-mail: [email protected].
Abstract: BACKGROUND:Nearly half of persons with Parkinson disease (PD) report fatigue as a factor in their fall history. However, it is unknown whether these self-reported falls are caused by a sensation of fatigue or performance fatigue. OBJECTIVE:We sought to investigate the influences of performance fatigue and age on postural control in persons with PD. METHODS:Individuals with PD (n = 14) underwent postural control assessments before (T0) and immediately after (T1) fatiguing exercise. Biomechanical data were gathered on participants completing a treadmill-induced, posterior-directed fall. Performance fatigue was produced using lower extremity resistance exercise on an isokinetic ergometer. Repeated measures ANCOVAs were used with age as a covariate to determine the effects of performance fatigue on biomechanical variables. RESULTS:After adjustment for age, there was a statistically significant difference in peak center of pressure (COP) latency during the support phase of recovery. Pairwise comparisons demonstrated a decrease in peak ankle displacement from T0 to T1. Age was also found to be significantly related to reaction time and peak knee displacement while participants were fatigued. CONCLUSIONS:The decreased peak COP latency, along with decreased ankle angular displacement, suggest that persons with PD adopt a stiffening strategy in response to backward directed falls. Postural stiffening is not uncommon in persons with PD and could be a risk factor for falls. Older individuals with PD demonstrate slower mobility scores and decreased reaction times in the setting of fatigue, suggesting a combined effect of the aging and fatigue processes.
Keywords: Parkinson’s disease, balance, falls, fatigue, performance fatigue
