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. 2015 Aug 13;2015(8):CD010459. doi: 10.1002/14651858.CD010459.pub2

Chang 2012.

Methods Randomised controlled trial
Design: 2‐arm parallel group design
Blindness: single‐blinded, technician scoring PSG and researchers responsible for statistical analysis not aware of group allocation
Participants Adults who experienced insomnia for at least 1 month, documented by a PSQI score > 5
N: 50
Age: mean 32 (SD 11) years; range 22 to 58 years
Sex: 3 males; 47 females
Setting: sleep laboratory
Country: Taiwan
Interventions

  1. Music group (N = 25)

    1. participants were encouraged to bring their own preferred music to listen to (N = 10)

    2. those who did not bring their own music, listened to researcher selected music (N = 15)

  2. Control group (N = 25)

    1. no intervention


Music characteristics: Rural Spring Field, Woman under the Moon (Chinese music), Going Home (Czech music), Destiny, Heart Lotus (Taiwanese music), and Memory (composed by the authors). Tempos ranged from 60 to 85 bpm, minor tonalities, smooth melodies, and no dramatic changes in volume or rhythm. The music was expected to be familiar to participants
Length of sessions: 45 minutes
Frequency of sessions: daily at bedtime
Duration of intervention period: 3 consecutive days
Outcomes

  • Sleep onset latency, minutes (PSG and morning questionnaire)

    • mean (SD) at baseline

    • GEE analysis estimating group differences post‐intervention

  • TST, minutes (PSG and morning questionnaire)

    • mean (SD) at baseline

    • GEE analysis estimating group differences post‐intervention

  • Sleep interruption, minutes (PSG, wake after sleep onset)

    • mean (SD) at baseline

    • GEE analysis estimating group differences post‐intervention

  • Sleep interruption (PSG and morning questionnaire, number of awakenings)

    • mean (SD) at baseline

    • GEE analysis estimating group differences post‐intervention

  • Sleep efficiency, % (PSG)

    • mean (SD) at baseline

    • GEE analysis estimating group differences post‐intervention

  • Stage 1, % of TST (PSG)

    • mean (SD) at baseline

    • GEE analysis estimating group differences post‐intervention

  • Stage 2, % of TST (PSG)

    • mean (SD) at baseline

    • GEE analysis estimating group differences post‐intervention

  • Stage 3 and 4, % of TST (PSG)

    • mean (SD) at baseline

    • GEE analysis estimating group differences post‐intervention

  • Stage REM, % of TST (PSG)

    • mean (SD) at baseline

    • GEE analysis estimating group differences post‐intervention.

  • Rested rating (morning questionnaire)

    • not included in this review (not part of primary or secondary outcomes defined in the protocol)


We contacted the author 16 December 2014 to obtain data on the raw post‐scores, but we have not yet received a reply
Notes Trial start and end dates: the trial was conducted from May 2010 to June 2011
Funding sources: the trial was funded by the National Science Counsil, Taiwan
Risk of bias
Bias Authors' judgement Support for judgement
Random sequence generation (selection bias) Low risk "Participants were randomly assigned (...), using the drawing of lots" (Chang 2012; p 924)
Allocation concealment (selection bias) Low risk "All lots (labels) are packed in a jar that was prepared by another person. Researchers therefore did not know beforehand which group each participant would be assigned to" (Chang 2012; p 924)
Blinding of participants and personnel (performance bias) 
 All outcomes High risk Due to the nature of the intervention, blinding of participants was not possible. It is unclear if this affected the objective sleep measures, but likely that it affected the subjective measures of sleep. Blinding of personnel at the sleep laboratory was not reported. Since the intervention was music, it is likely that they were not blinded
Blinding of outcome assessment (detection bias) 
 All outcomes Low risk The technician scoring the polysomnography and the researchers doing the statistical analyses were not aware to which group the data belonged
Incomplete outcome data (attrition bias) 
 All outcomes Low risk No dropouts and no missing data
Selective reporting (reporting bias) Unclear risk We found no published protocol on this study. Sleep efficiency, based on a self‐report questionnaire, was not reported. All other measures of interest were included in the analysis
Other bias High risk Baseline differences in measures of depression and self‐reported number of awakenings, with the music group experiencing significantly more depression and arousals than the control group