Effect of musical cues on gait in individuals with Parkinson disease with comorbid dementia

Background: Individuals with Parkinson disease and comorbid dementia (PDD) demonstrate gait impairments, but little is known about how these individuals respond to interventions for gait dysfunction. Rhythmic auditory stimulation (RAS), which utilizes music or other auditory cues to alter gait, has been shown to be effective for improving gait in individuals with PD without dementia, but has not been explored in individuals with PDD. Research question: Can individuals with PDD modulate their gait in response to music and mental singing cues? Methods: This single center, cross-sectional, interventional study included 17 individuals with PDD. Participants received Music and Mental singing cues at tempos of 90 %, 100 %, 110 %, and 120 % of their uncued walking cadence. Participants were instructed to walk to the beat of the song. Gait variables were collected using APDM Opal sensors. Data were analyzed using mixed effect models to explore the impact of tempo and cue type (Music vs Mental) on selected gait parameters of velocity, cadence, and stride length. Results: Mixed effects models showed a significant effect of tempo but not for cue type for velocity (F=11.51, p <.001), cadence (F=11.13, p <.001), and stride length (F=5.68, p =.002). When looking at the marginal means, velocity at a cue rate of 90 % was significantly different from 100 %, indicating participants walked slower with a cue rate of 90 %. Participants did not significantly increase their velocity, cadence, or stride length with faster cue rates of 110 % and 120 % Significance: Individuals with PDD appear to be able to slow their velocity in response to slower cues, but do not appear to be able to increase their velocity, cadence, or stride length in response to faster cue tempos. This is different from what has been reported in individuals with PD without dementia. Further research is necessary to understand the underlying mechanism for these differences.