Finger tapping as a proxy for gait: Similar effects on movement variability during external and self-generated cueing in people with Parkinson's disease and healthy older adults

Background: Rhythmic auditory cueing has been widely studied for gait rehabilitation in Parkinson's disease (PD). Our research group previously showed that externally generated cues (i.e., music) increased gait variability measures from uncued gait, whereas self-generated cues (i.e., mental singing) did not. These different effects may be due to differences in underlying neural mechanisms that could be discerned via neuroimaging; however, movement types that can be studied with neuroimaging are limited. Objective: The primary aim of the present study was to investigate the effects of different cue types on gait, finger tapping, and foot tapping, to determine whether tapping can be used as a surrogate for gait in future neuroimaging studies. The secondary aim of this study was to investigate whether rhythm skills or auditory imagery abilities are associated with responses to these different cue types. Methods: In this cross-sectional study, controls (n = 24) and individuals with PD (n = 33) performed gait, finger tapping, and foot tapping at their preferred pace (UNCUED) and to externally generated (MUSIC) and self-generated (MENTAL) cues. Spatiotemporal parameters of gait and temporal parameters of finger tapping and foot tapping were collected. The Beat Alignment Task (BAT) and Bucknell Auditory Imagery Scale (BAIS) were also administered. Results: The MUSIC cues elicited higher movement variability than did MENTAL cues across all movements. The MUSIC cues also elicited higher movement variability than the UNCUED condition for gait and finger tapping. Conclusions: This study shows that different cue types affect gait and finger tapping similarly. Finger tapping may be an adequate proxy for gait in studying the underlying neural mechanisms of these cue types.