People With Parkinson's Disease Who Freeze Exhibit Altered Quality of Daily-Life Walking Compared to Those Without Freezing.

People with Parkinson's disease and freezing of gait (PD+FOG) exhibit altered gait and turning compared to nonfreezing peers with PD (PD-FOG). However, less work has examined the effects of FOG status on daily-life mobility. Therefore, we compared daily-life gait and turning across PD+FOG and PD-FOG and related gait deficits to self-reported FOG severity and health-related quality of life (QOL). We collected daily-life mobility data over 7 days from 119 people with PD (PD+FOG = 47). Inertial sensors on the feet and lower back assessed 33 gait and balance outcomes. One-way ANCOVAs assessed the effect of FOG status on mobility. Five variables reflecting gait and turning quality were significantly worse in PD+FOG compared to PD-FOG after Holm correction: smaller turn angles, smaller foot pitch at initial contact, and increased variability of double-support time, stride length, and pitch at toe-off. Of these outcomes, two (turn angle & stride length variability) were significantly correlated with freezing severity, and 4 (turn angle, stride length variability, pitch at initial contact and pitch at toe-off variability) related to QOL. Turns per hour also related to QOL. In sum, PD+FOG exhibited worse daily-life gait quality (small turn angle and foot angle at heel strike and increased gait variability) and these outcomes were related to QOL and FOG severity. Daily-life gait quantity (number of turns, strides, and gait bouts per hour) was less affected by FOG. These results provide insight into daily-life mobility of PD+FOG, and support interventions aimed at quality of gait and turning for PD+FOG.