Standardizing music characteristics for the management of pain: A systematic review and meta-analysis of clinical trials

Purpose: To evaluate if music characteristics like tempo, harmony, melody, instrumentation, volume, and pitch, as defined by musical theory, are described in randomized clinical trials (RCTs) evaluating the effects of music listening on the quantified pain perception of adults, and if these characteristics influence music's overall therapeutic effect. Methods: A systematic review and meta-analysis of RCTs evaluating music-listening for pain management on adults was performed according to the Preferred Reporting Items for Systematic Review and Meta-Analyses statement. The databases Pubmed, Scopus, SCIELO, SpringerLink, Global Health Library, Cochrane, EMBASE, and LILACS were searched. Studies published between 2004 and 2017 with quantified measurements of pain were included. Quality was evaluated using the Scottish Intercollegiate Guidelines Network methodology checklist for RCT, and effect sizes were reported with standardized mean differences. Results: A total of 85 studies were included for qualitative analysis but only 56.47% described at least one music characteristic. Overall meta-analysis found a significant effect, with high heterogeneity, of music for pain management (SMD -0.59, I2 = 85%). Only instrumentation characteristics (lack of lyrics, of percussion or of nature sounds), and 60-80 bpm tempo were described sufficiently for analysis. All three instrumentation characteristics had significant effects, but only the lack of lyrics showed an acceptable heterogeneity. Conclusions: Results show that music without lyrics is effective for the management of pain. Due to insufficient data, no ideal music characteristics for the management of pain were identified suggesting that music, as an intervention, needs standardization through an objective language such as that of music theory.