BACKGROUND: Dementia is a common and serious neuropsychiatric syndrome, characterised by progressive cognitive and functional decline. The majority of people with dementia develop behavioural disturbances, also known as behavioural and psychological symptoms of dementia (BPSD). Several non-pharmacological interventions have been evaluated to treat BPSD in people with dementia. Simulated presence therapy (SPT), an intervention that uses video or audiotape recordings of family members played to the person with dementia, is a possible approach to treat BPSD. OBJECTIVES: To assess the effects of SPT on behavioural and psychological symptoms and quality of life in people with dementia. SEARCH METHODS: We searched ALOIS (the Specialised Register of the Cochrane Dementia and Cognitive Improvement Group), CENTRAL (The Cochrane Library) (9 February 2016), MEDLINE Ovid SP (1946 to 6 January 2017), Embase Ovid SP (1972 to 6 January 2017), PsycINFO Ovid SP (1806 to 6 January 2017), CINAHL via EBSCOhost (1980 to 6 January 2017), LILACS via BIREME (all dates to 6 January 2017), ClinicalTrials.gov (ClinicalTrials.gov) (all dates to 6 January 2017), and the World Health Organization (WHO) Portal (apps.who.int/trialsearch) (all dates to 6 January 2017). We also checked the reference lists of relevant articles to identify any additional studies. SELECTION CRITERIA: Randomised and quasi-randomised controlled trials, including cross-over studies, that evaluated the efficacy of SPT, consisting of personalised audio or videotape recordings of family members, in people with any form of dementia. DATA COLLECTION AND ANALYSIS: Two authors independently selected studies, assessed risk of bias and extracted data. No meta-analyses were conducted because of substantial heterogeneity among the included studies. MAIN RESULTS: 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 resultsNone of the studies evaluated quality of life or any of our secondary outcome measures (performance of activities of daily living, dropout and carer burden). AUTHORS' CONCLUSIONS: 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.