Analyzing Entrainment of Finger Tapping and Auditory Stimuli in Humans

Accuracy and precision in synchronization and phase coherence have often been used to assess entrainment. However, discrepancies between neural entrainment and behavioral performance have been reported. This study aimed to evaluate motor entrainment to auditory stimuli through phase synchronization measured via finger tapping. Twenty healthy adults participated in a tapping task synchronized with auditory tones presented at six inter-tone intervals (400, 500, 600, 750, 1000, and 2000 ms) over a five-minute period per condition. Phase synchronization strength was quantified from the time-series data of auditory cues and tapping responses. Surrogate data analysis was used to assess the significance of phase synchronization, and effect sizes (Cohen's d) were calculated for each condition. Results showed significant phase coherence at 400, 500, 600, 750, and 1000 ms, with the strongest effect size observed at 400 ms. This condition also had the lowest likelihood of false positives in entrainment detection, suggesting that the 400 ms interval is the most reliable for evaluating motor-auditory entrainment.