Music tuned to 432 Hz versus music tuned to 440 Hz for improving sleep in patients with spinal cord injuries: a double-blind cross-over pilot study

Among people with spinal cord injuries, sleep disorders are considered one of the top well-being priorities. Some studies suggest that listening to music promotes sleep and improves its quality. These studies usually used music standardised at the frequency of 440 Hz. The aim of the present study is to compare the effects of listening to music tuned to 440 Hz and music tuned to 432 Hz on sleep in patients with spinal cord injuries.

Double-blind cross-over pilot study in a single Italian Spinal Unit. 12 patients with spinal injuries were provided with mp3 players loaded with their favourite music tuned to 440 Hz or 432 Hz. They were invited to listen to music for 30 minutes each day, in the two periods of the study. "Sleep Scale for Medical Study" modified for this study, and the "Perceived Stress Scale" were chosen.

The participants were eight males (mean age =58.12, SD ±13.62), and four females (mean age =56.25, SD ±14.17). Five were quadriplegics and seven were paraplegics. Listening times and wash-out periods were variable. The stress decreased, but not significantly, with listening to music at both frequencies. After listening to music at 432 Hz there was a significant improvement in sleep scores (+3.6, p=0.02), while there was no improvement in sleep scores listening to music at 440 Hz (-1.50, p=0.34).

The results suggest that further studies on music interventions at 432 Hz should be performed. It is advisable to increase sample sizes and use a range of different research methods.