Slow pentatonic sequences facilitate sleep onset

Previous literature on the effects of musical stimuli in facilitating sleep onset has produced mixed results. This study aimed to test the efficacy of very slow pentatonic melodic sequences in facilitating sleep onset compared with a silence control condition. Twenty-two participants slept for four nights in a sleep lab with polysomnographic recording. The four nights included a first adaptation night and three experimental nights. Two nights included musical stimulation with speed in the delta and sub-delta range (1 Hz and 0.2 Hz, respectively), and one night included silence (control). The two musical stimulations consisted of pentatonic melodic sequences. Music was played from lights off until the onset of the slow-wave sleep (SWS) stage. Sleep onset latency, N1 duration, N2 latency, first N2 duration, SWS latency, sleep architecture, and spectral power of the interval from lights off to sleep onset were assessed from polysomnographic recordings. The results showed shorter latencies for sleep onset, N2, and SWS latencies with 0.2 Hz pentatonic sequences. Spectral analysis of the electroencephalography (EEG) data from lights off to sleep onset showed a significant increase in delta EEG oscillations in both musical conditions. Very slow musical stimulation can facilitate sleep onset.