Given the limited efficacy of pharmacological treatments, the use of musical intervention as a non-drug treatment for patients with Alzheimer's disease is strongly recommended. Musical interventions appear to improve the socio-emotional and cognitive functioning of these patients, and benefits increase when patients' motor skills are engaged. Our study evaluates the factors that may influence patients' socio-emotional and motor engagement during musical activities and measures their sensorimotor synchronisation (SMS) abilities. Participants were asked to tap in time to a metronomic or musical rhythm, in the presence of a musician who performed the task with them. The musician's presence was either physical (live condition) or virtual (video condition). Two tempos were tested: a slow tempo (inter-onset interval of 800 ms) and a fast tempo (inter-onset interval of 667 ms). The results showed that patients spontaneously produced more rhythmic movements in response to the music than to the metronome. However, the consistency and accuracy of sensorimotor synchronisation was better with the metronome than with the music and was also better when the musician was present through the video rather than in person. These effects were modulated by the tempo of the auditory sequences. These results confirm the importance of the musical context and social interactions on these different performances. By simultaneously evaluating the sensorimotor synchronisation of the hands, spontaneous motor behaviours, and socio-emotional behaviours using quantitative and controlled measurements, this study validates a multimodal approach to evaluating patients' engagement in a musical task. These initial results provide promising prospects in terms of application while providing clinicians and researchers with a rigorous methodology for understanding the factors that are at the origin of the therapeutic benefits of musical activities on the behaviour and well-being of patients and their caregivers.
Keywords: Alzheimer's disease; motor activity; music therapy; social interaction.