Control of Gait Cadence Transitions Are Abnormal in Parkinson's Disease
Over fifty percent of people with Parkinson’s disease (PD) will eventually experience freezing of gait (FOG). FOG predominantly occurs during gait transitions (e.g. slowing down, turning), but little is known about the relationships between step length, gait speed, and cadence during transitions. We hypothesized that healthy young adults (HYA), but not people with PD and FOG, would maintain linear relationships of gait speed to cadence and gait speed to step length.
Fourteen healthy young adults and eight participants with PD (68 +/- 5 years, 4 with FOG) walked a 10m-long figure-eight path under four conditions: (1) walking at their natural cadence (uncued), (2) walking while cued (with tones) at their natural cadence or (3) at 120% of their natural cadence (fast), and (4) trials where the cues randomly transitioned between natural and fast cadences. The slope and correlation coefficients (R^2 values) of the three primary gait relationships (cadence-to-speed, cadence-to-step length, and step length-to-gait speed) in three walking states (steady state, during cadence transitions, and prior to turns) were calculated.
A linear mixed model ANOVA on the cadence-to-speed slopes showed a significant effect of group (p < 0.005), but not walking state, with HYAs showing larger positive slopes and R2 values than PD. There were no significant differences in the other relationships. Cadence-to-step length slopes were near zero for HYA, while 5 of 8 PD exhibited negative slopes. Most participants had significant positive relationships between step length and gait speed for all states.
In conclusion, HYAs use a consistent strategy to predictably control the relationship between cadence and gait speed during steady-state and gait transitions, but this relationship was not maintained in PD. This research could help identify alterations in the neural control system associated with Parkinson’s disease gait impairment, including FOG.