Abstract: Three trials with 144 participants met the inclusion criteria. Two of the trials had a randomised cross-over design, one was a cross-over trial which we classified as quasi-randomised. Participants in the included studies were people with dementia living in nursing homes. They were predominantly women and had a mean age of over 80 years. SPT was performed using an audio or video recording prepared by family members or surrogates. It varied in its content, frequency of administration and duration. All the studies compared multiple treatments. In one study, SPT was compared with two other interventions; in the other two studies, it was compared with three other interventions. Specifically, SPT was compared to usual care, personalised music (two studies), a 'placebo' audiotape containing the voice of a person (two studies), and one-to-one social interaction performed by trained research assistants (one study). In terms of outcomes evaluated, one study considered agitation and withdrawn behaviour (both assessed with three methods); the second study evaluated verbal disruptive behaviour (assessed with three methods); and the third study evaluated physically agitated behaviour and verbally agitated behaviour (the method used was not clearly described). According to the GRADE criteria, the overall quality of the evidence was very low due to very small numbers of participants and risk of bias in the included studies; (none of the trials was at low risk of selection bias; all the trials were at high risk of performance bias; one trial was at high risk of attrition bias; and all had unclear selective reporting). Because of variation in the participants, the format of SPT, the comparison interventions, and the measures used to assess outcomes, we judged the results unsuitable for a meta-analysis. Within each trial, the effect of SPT on behaviour, compared to usual care, was mixed and depended on the measure used. Two trials which included a personalised music intervention reported no significant differences between simulated presence and music on behavioural outcomes. Because the overall quality of the evidence was very low, we were very uncertain regarding all the results None of the studies evaluated quality of life or any of our secondary outcome measures (performance of activities of daily living, dropout and carer burden). We were unable to draw any conclusions about the efficacy of SPT for treating behavioural and psychological symptoms and improving quality of life of people with dementia. New high-quality studies are needed to investigate the effect of SPT.

Plain-language summary: We looked for trials which compared SPT to usual care or to another treatment. Ideally, people with dementia should have been randomly allocated to one or other treatment, but we also included trials even if treatment allocation was not strictly random. We found three trials which met our inclusion criteria. The 144 participants were all living in nursing homes. The majority were women with an average age of over 80 years and severe dementia. The way SPT was administered was different in each trial. All the trials used more than one comparison treatment, which differed between trials. The trials all attempted to measure an effect on agitated behaviours, but used different approaches. Because the trials were so different from each other, we were not able to pool the results. Individually, each trial reported different methods to assess the effect of SPT on behavioural problems and the results varied depending on the method used to measure the outcome. None of the studies assessed quality of life, effect on daily activities, effects on caregivers, or how likely participants were to drop out of the study. The studies were small and all had problems with their methods which could have biased their results. Hence, we thought the overall quality of the evidence was very low, meaning we cannot be at all confident in the results. Not enough high-quality research has been done to allow us to judge whether SPT can help people with dementia who are distressed or agitated.