Beyond the Metronome: Auditory Events and Music May Afford More than Just Interval Durations as Gait Cues in Parkinson's Disease

An explanation for these improvements is that the cerebellar-thalamocortical circuits in the brain that support detection and synchronization to regular perceptual events are relatively preserved in PD, whereas the basal ganglia-thalamocotrical network that supports actions to one's own internal beat are impaired by the disease (Dalla Bella et al., 2015). Because the timing for action is externalized in RAS, each movement (step) can be matched to each perceptual cue (beat), resulting in a more stable gait pattern with larger steps (Nombela et al., 2013). According to the model, inherited from research on sensorimotor synchronization (SMS) more generally, successfully cued performance is defined as the adjustment of intervals between movement boundaries such that each movement begins/ends at the same moment in time as the onset of the perceptual event (beat). [...]the idealization of gait cueing as SMS may place an insurmountable burden on PD patients, and indeed is likely an unrealistic picture of what actually occurs during RAS gait cueing, given that most reported research is vague about how participants are instructed to “walk to the sounds” and generally analyse effects on global measures of gait (e.g., average step cadence) rather than step-to-beat synchronization. [...]the action-relevant gravel sounds specified parameters of walking beyond merely step-to-step intervals which was useful in guiding stepping movements in people with PD. Music as Richly-Structured, Action-Relevant Sound Events One rich source of action-relevant auditory events is music.