Music is neurologically special in the way that it stimulates many parts of the brain at once. This means that even if parts of the brain are damaged, music can still reach other parts.
Evidence for the power of music generally
A major review in 2017 confirmed that ‘among sensory simulation interventions, the only convincingly effective intervention for reducing behavioural symptoms (specifically agitation and aggressive behaviour) was music therapy’. that year showed “music intervention significantly reduces agitated behaviours in demented people.”
In 2018, a concluded that there was a need for more research in the area, in part because of the lack of consistency in methodologies across different studies. The reviewers were reasonably confident that music could affect mood and depression in people with dementia but could not draw definitive conclusions about other effects. They recommended that future research should specifically consider the duration of effects in relation to the duration of sessions.
The power of playlists
Practice of Playlist for Life is based upon the evidence-based developed over the course of twenty years at Stanford University. In particular, Playlist for Life promotes the use of i.e. timing listening sessions for thirty minutes before difficult times or activities.
The protocol describes how correct use of playlists is proven to bring about reductions in (1) use of psychotropic medication (2) use of restraints (3) stress and distress (4) wandering.