Eligible for inclusion were randomised controlled trials (RCTs), controlled clinical trials, and cohort studies that evaluated one music-related experience or a combination of music-related experiences, such as singing, listening, performing, rhythmic exercising, and improvising. Uncontrolled before-and-after studies and case studies were excluded. Participants had to be older people formally diagnosed with any type of dementia. Primary outcomes of interest were changes in psychological symptoms (depression and anxiety), and behaviour (agitation, apathy, elation, and irritability). Secondary outcomes of interest were changes in cognitive function, and activities of daily living.
Over half of the included studies were conducted in Asia; the rest were conducted in Europe (none in the UK), the USA, or Australia. Patients had senile dementia of Alzheimer's type, vascular type, Parkinson's type, or mild-to-severe mixed types. The mean age (where reported) ranged from 72.6 years to 89.5 years. Most studies were of combined music-related experiences, often based on music that was familiar to participants. The comparators were usual care (not defined). Various professionals (most of whom were music therapists) or students delivered the interventions, which lasted (on average) for 36 minutes per day, on two-to-three days a week, for 10 weeks. Various outcome measures were used (reported in the paper).
Two reviewers independently selected studies for inclusion. Disagreements were resolved by consensus, or with the involvement of a third reviewer, if necessary.