Gait and gait-related activities and fatigue in Parkinson's disease: what is the relationship?

PURPOSE: To explore the relationship between gait and gait-related activities and fatigue in Parkinson's disease (PD). METHOD: Twenty people with idiopathic PD (12 male, 8 female; mean age 64.6 +/- 7.96) and 10 age, sex and education matched controls (6 male, 4 female; mean age 63.5 +/- 7.03) wore an activity monitor for approximately 24 h, from which the percentage time walking and standing, the number of periods of walking greater than 10 sec were derived. Prior to monitoring, levels of fatigue (Multi-dimensional Fatigue Index, MFI) were evaluated. RESULTS: Activity data related to gait were compared for the waking hours of the day, reflected by the period between 6 am and 10 pm. Overall, PD subjects demonstrated reduced activity compared to controls, however there was no significant difference between PD and controls for the percentage time spent walking (p = 0.149), standing (p = 1.0) or engaged in periods of walking that were greater than 10 sec (p = 0.059). Significantly greater levels of fatigue were experienced by PD subjects in all MFI domains compared to controls (physical p = 0.001; activity p = 0.001; general p = 0.001; mental p = 0.028; motivation p = 0.024). There was no clear association between activity and fatigue in PD subjects. CONCLUSIONS: Evidence of increased fatigue is not supported by evidence of significantly decreased levels of activity in PD subjects. The relationship between activity and fatigue therefore remains unclear, highlighting the complex nature of the relationship between these factors. Further work is required to increase our understanding of the impact of fatigue on gait and gait-related activity so that improved management can be explored