Lord 1993

Methods	RCT (parallel), total duration of 6 months. No information provided about begin and end dates of the study.
Participants	Country: USA. N = 60 (42 female, 18 male) residents in a privately funded home for older people. Age range : 72 to 103 years. Diagnosis of dementia: all clinically diagnosed with dementia of the Alzheimer's type (method not specified). The 60 participants were "randomly selected from approximately 200 patients clinically diagnosed as having Alzheimer disease".
Interventions	(1) Mixed active‐receptive group intervention with music listening and playing along (30‐minute sessions delivered 6 times per week for a period of 6 months). (2) Jigsaw puzzle activities (30‐minute sessions 6 times per week for a period of 6 months). (3) No special treatment, but involved in usual recreational activities of drawing, painting, and watching television.
Outcomes	Cognition, social skills (interaction) and emotional well‐being as assessed with a self‐made questionnaire: general impressions (assessed before and after intervention period) + participants' disposition and social coaction (assessed with a focused 30‐sec, observation on 1 subject for 3 periods during each activity session for the first 2 weeks and final 2 weeks of the study (resulting in 36 observations for each participant in the first 2 weeks and 36 observations in the last 2 weeks).
Notes	No information reported about funding. Randomization was stratified by gender.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	High risk	Quote: "The patients were non‐systematically separated into three groups of equal size".
Allocation concealment (selection bias)	High risk	Quote: "To assure equal representation by gender, the random division was implemented first with the female and then with the male patients". No further information provided on the method to conceal the allocation sequence.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Not possible to blind the convener and participants.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	No information was provided on blinding of the outcome assessors.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	No information provided.
Selective reporting (reporting bias)	Unclear risk	Not enough detail was reported about the outcome measures. No study protocol available.
Other bias	High risk	We were unable to reproduce the results. No statistical tests were reported for the between‐group comparisons, only for the within‐group. The article reports that the number of correct answers for each of the 3 groups was summed for baseline and post treatment, and then a 1‐way analysis of variance conducted. No information on how the data were analysed, whether the baseline was used as a covariate. Table 1 analysis of variance, although showing significant differences between the 3 therapies, does not seem valid. For example, the degrees of freedom within groups are not correct. To interpret this table far more information is required. Even if the results in table 2 are accepted, all that can be deduced is that the treatments were different. They may be different in the level of participation in the therapies, but that does not explain whether the therapy itself brought any benefit.