Rhythmic movements mimicking tremor under different metronome conditions.

Rhythmic movements mimicking tremor are commonly used as a control condition in tremor physiology studies, yet the influence of different metronome modalities on performance has not been systematically examined. We compared auditory, visual, and combined auditory-visual metronome guidance in terms of frequency accuracy, temporal stability, and persistence following cueing removal to identify a suitable metronome condition for tremor simulation. Nineteen healthy volunteers performed 2 Hz thumb abduction-adduction movements under auditory, visual, and combined auditory-visual metronome conditions. Each trial included a 30 s metronome-guided phase followed by a 30 s post-metronome phase. Surface EMG recordings were analyzed using repeated-measures ANOVA and correlation analyses. Frequency accuracy and temporal stability did not differ significantly between metronome types. However, auditory and combined auditory-visual cueing descriptively showed lower frequency error than visual cueing during metronome guidance. Guided-to-unguided temporal stability correlations were significant for auditory and combined auditory-visual cueing, but not for visual cueing, with combined cueing showing a relatively higher correlation. Although no significant group-level superiority was observed, the overall pattern of findings suggested that the combined auditory-visual metronome may represent a suitable metronome condition for rhythmic movements mimicking tremor.