Active and Passive Rhythmic Music Therapy Interventions Differentially Modulate Sympathetic Autonomic Nervous System Activity.

Dysregulation of the autonomic nervous system (ANS) and the hypothalamic-pituitary-adrenal (HPA) axis has been implicated in psychiatric disorders. Music therapy (MT) has been shown to modulate heart-rate variability (HRV) and salivary stress markers, physiological markers of the ANS and HPA axes, respectively. Given the prominent role of arousal and stress physiology in many psychiatric disorders, MT has the potential to provide therapeutic benefits in psychiatry. Active MT requires patients to engage rhythmically with music; in contrast, passive MT requires patients to listen to music, eliminating the rhythmic movement seen in active MT. Yet, it remains unknown whether active or passive MT differentially modulates arousal and stress physiology. We contrasted the effects of active and passive MT experiences to examine the differential impact of rhythmic movement on the ANS and HPA axes in healthy participants. Individuals (N = 16) participated in a crossover study of 40 min of an active MT and a passive MT intervention. HRV recordings and saliva samples were collected both before and after each intervention. The high-frequency component (HF) and the ratio of low-frequency to high-frequency components (LF/HF) were calculated as cardiac markers of parasympathetic and sympathetic ANS activation, respectively. Saliva samples were analyzed for alpha-amylase and cortisol, markers of the sympathetic ANS and HPA axes, respectively. Active MT and passive MT interventions differentially modulated LF/HF, where active MT decreased LF/HF and passive MT increased LF/HF. These results indicate that MT affects the ANS and suggests that differences in engagement between active MT and passive MT lead to a differential modulation of the sympathetic ANS.

Intrinsic Rhythmicity Predicts Synchronization-Continuation Entrainment Performance.

Rhythmic entrainment-defined as a stable temporal relationship between external periodic signals and endogenous rhythmic processes-allows individuals to coordinate with environmental rhythms. However, the impact of inter-individual differences on entrainment processes as a function of the tempo of external periodic signals remain poorly understood. To better understand the effects of endogenous differences and varying tempos on rhythmic entrainment, 20 young healthy adults participated in a spontaneous motor tempo (SMT) task and synchronization-continuation tasks at three experimental tempos (50, 70, and 128 bpm; 1200, 857, and 469 ms inter onset interval (IOI)). We hypothesized that SMT task performance and tempo would influence externally paced synchronization-continuation task behavior. Indeed, intrinsic rhythmicity assessed through the SMT task predicted performance in the externally paced task, allowing us to characterize differences in entrainment behavior between participants with low and high endogenous rhythmicity. High rhythmicity individuals, defined by better SMT performance, deviated from externally paced pulses sooner than individuals with low rhythmicity, who were able to maintain externally paced pulses for longer. The magnitude of these behavioral differences depended on the experimental tempo of the synchronization-continuation task. Our results indicate that differences in intrinsic rhythmicity vary between individuals and relate to tempo-dependent entrainment performance.