The world’s population is ageing rapidly and the number of people with severe age-related brain diseases is increasing. 1 More than 80% of the heavy economic burden of chronic brain diseases is due to costs other than acute treatment and care.2,3 This burden has raised the need to pursue new cost-effective, easily applicable rehabilitation strategies, both independent of and complementary to traditional methods such as physiotherapy, occupational therapy, and speech therapy. Since neurogenesis in the adult brain has no known clinically meaningful effect on brain recovery, functional restoration relies upon the ability of spared neurons to compensate for lost function by growing neurites and forming new synapses to rebuild and remodel the injured networks.4–8
This functional restoration is thought to be achieved in traditional rehabilitation strategies by targeted training of the weakened function.9–12 An alternative strategy is to increase the overall level of brain activity through sensory and cognitive stimulation.13
Music listening improves neuronal connectivity in specific brain regions of healthy participants,14–17 and musical activities, such as playing an instrument, promote neural plasticity and induce grey and white matter changes in multiple brain regions, especially frontotemporal areas.18–20 Music listening was efficacious in the recovery of postoperative patients who had various types of major surgery, as measured by several outcomes such as levels of pain and anxiety, use of analgesics, and patient satisfaction,21 suggesting that music might also enhance neurological rehabilitation.
Formal music-based intervention can be defined as active intervention (eg, creating music, playing an instrument, singing, or musical improvisation) or receptive intervention (eg, music listening) that is administered by a credentialed music therapist (panel).
Although a Cochrane review evaluated the effect of music intervention on recovery of acquired brain injury,22 a comprehensive overview of music-related interventions in the rehabilitation of the major neurological diseases, including degenerative ones, is needed. In this Review, we appraise the randomised controlled trials investigating the effects of music-based interventions in the rehabilitation of patients with stroke, dementia, Parkinson’s disease, epilepsy, or multiple sclerosis. For comparison of the studies included, we define the effect sizes of improvements in the specified outcome as small (Cohen’s d≥0•2), medium (d≥0•5), or large (d≥0•8). Effect size was defined as the mean change in outcome before and after treatment in the treatment group minus the mean pre–post change in the control group, divided by the pooled pretest standard deviation.
Music-based interventions for stroke
Stroke is one of the leading causes of long-term disability worldwide.23 Of the major neurological disorders, the strongest evidence for efficacy of music-based interventions has been reported for stroke. We identified 16 randomised controlled trials that used music as an add-on therapy for stroke-related neurological and neuropsychiatric disturbances (table).24–39 The assessed outcomes included motor functions, such as gait and upper extremity function;24,25,27,30,31,34–39 language functions;26,28,29 cognitive functions, such as memory and attention;28,33 mood;28,33,36 and quality of life.30,36 These outcomes were measured with various standard motor tests (eg, Fugl-Meyer Assessment,
the Box and Blocks Test, Berg Balance Scale, and NineHole Peg Test), clinical neuropsychological assessments (eg, CogniSpeed, Revised Wechsler Memory Scale), standard language function assessments (eg, Boston Diagnostic Aphasia Examination), and questionnaires (eg, Stroke Impact Scale, Profile of Mood States, and Stroke and Aphasia Quality of Life Scale-39).
Additionally, computer-based movement analyses,30,35,38,39 MRI analysis,28,31,33 magnetoencephalography,31 or electroencephalography34 were used to assess motor performance and neuroplasticity. Metronome-like rhythmic stimulus was used in five studies of stroke-related motor paresis.30,31,36,37,38 The participants’ favourite music, selected through interview, was used in three studies,28,32,33 although the genres of favourite music were not reported.
