Effects of broadband music and audible band music on relaxation states and cognitive function in young adults: a randomized controlled trial.

Background: Although broadband music with inaudible high-frequency components may benefit human well-being, this research area is largely unexplored and lacks sufficient studies on the topic. This study aimed to investigate and compare the effects of broadband and audible band music on relaxation states and cognitive function in young adults.

Methods: A single-blind randomized controlled trial was conducted in a professional soundproof laboratory from December 22, 2022, to January 18, 2023 with 32 participants randomly assigned to two groups, "Day 1 broadband + Day 2 audible band" (n = 16) and "Day 1 audible band + Day 2 broadband" (n = 16), listening to either broadband or audible band music (the same music piece played on the piano and harp) for two sessions of 15 min each on two consecutive days. Cognitive function was measured using CNS Vital Signs at pre-listening, after the 1st session, and after the 2nd session, while heart rate was monitored throughout the experiment. Visual Analog Scale was also administered for self-reported arousal, stress, thinking ability, and attention following each listening session.

Results: No significant differences were found in heart rate, cognitive flexibility, and executive function between the broadband listening group and the audible band-listening group (p > 0.05). However, the broadband group exhibited significant differences in mean heart rate at several time points, as well as a significant improvement in VAS stress level during the 2nd listening session compared to the 1st (p < 0.05). On the other hand, significant improvements in cognitive flexibility and executive function were observed in the audible band group across different time points (p < 0.05).

Conclusion: Comparative analysis showed that broadband and audible band music influenced cognitive function differently. Short-term audible band music listening significantly improved cognitive flexibility and executive function, while short-term broadband music listening significantly reduced reaction time in cognitive tests. Additionally, broadband music consistently resulted in lower mean heart rates compared to audible band music at all time points, suggesting that it may be more effective in promoting relaxation and reducing stress, although these differences were not statistically significant. Since the cognitive enhancing effects of broadband music may be counteracted by the drowsy effect of the selected relaxing music, using different types of music may be necessary to confirm its effects in future studies.