Auditory Countermeasures for Sleep Inertia: An Ecological Study Examining the Influence of Melody and Rhythm.

Sleep inertia is the potentially harmful decline in cognition that occurs upon and following awakening. Sound has been shown to counteract the negative symptoms of sleep inertia, with a recent study revealing that an alarm perceived as melodic by participants displayed a significant relationship to reports of reductions in perceived sleep inertia. This current research builds on these findings by specifically testing the effect melodic and rhythmic stimuli exhibit on sleep inertia for subjects awakening in their habitual environments. Two test Groups (A & B; N = 10 equally) completed an online psychomotor experiment and questionnaire in two separate test sessions immediately following awakening from nocturnal sleep epochs. Both groups responded to a Control stimulus in the first session, while in the second session, Group A experienced a Melodic treatment, and Group B the Rhythmic. The results show that the melodic treatment significantly decreased attentional Lapses, False Starts and had a significantly improved PVT Performance Score than the Control. There was no significant result for Reaction Time or Response Speed. Additionally, no significant difference was observed for all PVT metrics between the Control - Rhythmic conditions. The results support melodies potential to counteract symptoms of sleep inertia by the observed increase in participant vigilance following waking. Specifically, a melodically rhythmic contour is highlighted as a significant musical treatment noteworthy of consideration when designing alarm compositions for the reduction of sleep inertia. As auditory assisted awakening is a common within modern society, improvements in alarm sound design may have advantages in domestic and commercial settings.