Study protocol for PIANo-1: Personalized Investigation of music's effect on Attention in a series of N-of-1 trials

Focus and concentration are influenced by various environmental factors, such as listening to music. Recent research highlights the individualized nature of music's effects on concentration, as responses vary significantly between individuals based on music genres and personal preference. Traditional population-based studies often obscure these between-person differences, while N-of-1 trials, which are individual crossover trials, can provide a personalized approach by allowing each participant to serve as their own control. This study design is particularly suited for examining how self-selected music genres might enhance or alter concentration in each individual. By leveraging an N-of-1 trial design, this study aims to contribute to the growing body of research investigating personalized cognitive interventions, providing insights into individual effects and variations in response to music.

The study will include approximately 23 participants, who will be allocated to a block-randomized sequence with two cycles, each consisting of 3-min periods of listening to music (intervention, A) and 3 min of no music (control, B) in random order. Study participants will select one of fourteen predefined music genres, with or without lyrics, as their intervention. A playlist with preselected songs from this genre will be played and compared to not listening to music. To minimize the effects of carryover and concentration loss during the study, a 1-min break is planned between each period, resulting in a total duration of around 15 min. Concentration will be assessed by the number of correct classifications of a digital version of the Stroop test within each period. After each period, a short questionnaire will be administered to collect self-assessed concentration and stress scores. Additionally, physiological biomarkers will be assessed using wearables such as Electroencephalography, Heart Rate Variability, Electrodermal Activity, and eye- and pupil-movement data. In the statistical analysis, Bayesian generalized linear mixed models will be used to estimate the intervention effects of music on correct answers of the Stroop task on the individual level and population level.

This study will provide insights into the personalized effects of music on concentration, providing a blueprint for individuals on how they may test and improve their concentration.