Cho 2016.

Methods	RCT (parallel) with 3 groups. Intervention provided in October 2015, for 4 weeks
Participants	Country: USA. Veterans Affairs skilled nursing home facility 52 people with dementia were randomised, and 35 or 36 (for different outcomes) were included in the analyses (experimental group: 14; control group 1: 14; control group 2: 7 for quality of life and 8 for affect outcomes). Age, mean (SD), range: experimental group: 85.1 (SD 8.7), 67–99 years; control group 1: 87.9 (SD 5.9), 75–98 years; control group 2: 87.0 (SD 6.0), 74–97 years. There were only 3 women in each of the 3 groups of experimental group: 18; control group 1: 17; control group 2: 17. Mean BIMS scores (SD): experimental group: 10.2 (SD 4.4); control group 1: 10.2 (SD 4.0); control group 2: 9.9 (SD 3.6) (BIMS scores 8–12 refer to moderate impairment). All participants were Caucasians. Residents were included when they had a diagnosis of dementia, were aged ≥ 65 years, had no significant hearing impairment and were able to sit in a chair or wheelchair for ≥ 1 hour. Residents with severe psychiatric conditions, or receptive or expressive language problems were excluded.
Interventions	Experimental group: music therapy‐singing group: by "a music therapist with over 15 years of experience with dementia care." Control group 1: music listening group by nursing home activity assistants (for the purpose of our review, we regarded this as a control condition). The assistants "did not have same level of training as the music therapist, especially in facilitating a group process." Control group 2: TV watching group: control condition, watching a DVD All 3 groups ran 8 × 40‐minute sessions in a period of 4 weeks (twice a week)
Outcomes	Outcome: quality of life (QOL‐AD). Quality of life was assessed directly from the person with dementia. It was evaluated twice, once before the first intervention session and once after the last (8th) intervention session. An additional research question referred to differences in quality and affect over time between the 3 BIMS categories.
Notes	Specific population (more men than usual in nursing home populations) Randomisation was stratified by dementia severity (mild, moderate, severe based on BIMS score). Other outcomes were general positive affect and negative affect measured with the PANAS. Funding (author personal communication): institutional support with no external funding
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	For the random assignment, the list of participants was given to another nursing home activity assistant with specially assigned numbers in place of the participants' names.
Allocation concealment (selection bias)	Low risk	The participants' names were not revealed to the nursing home activity assistant who was responsible for the random assignment until the randomisation process was completed to ensure allocation concealment. The nursing home activity assistant randomly assigned participants to 1 of the 3 conditions within each stratum of the BIMS score using a random number table from a statistical text book.
Blinding of participants and personnel (performance bias) All outcomes	High risk
Blinding of outcome assessment (detection bias) All outcomes	High risk	Nursing home activity assistants who were involved in assessing the outcomes were not blinded.
Incomplete outcome data (attrition bias) All outcomes	High risk	Of the 17 participants who were assigned to the control (TV watching) group, only 8 (47%) completed the intervention. Dropout in this group was larger than for the other groups (with 83% in music therapy‐singing group and 82% in music listening group completed). Quote: "Furthermore, the participants' preferences for the TV group were not assessed, whereas music programs for singing and listening group were created based on their music preferences. This may have closely related to the inconsistent results regarding affect in the TV group, as well as the highest drop‐out rate of participants assigned to the TV group. Out of 17 participants who were assigned to the TV group, nine dropped out over the course of the study, and only eight completed the intervention."
Selective reporting (reporting bias)	Unclear risk	The study was not registered.
Other bias	Low risk