Music therapy works because music activates multiple neural systems at once:

• Rhythmic Auditory Stimulation (RAS) uses steady beats to retrain gait in stroke and Parkinson's patients. The brain's motor cortex syncs to the rhythm, and patients walk more smoothly.
• Melodic Intonation Therapy helps stroke patients who have lost speech. Singing uses different neural pathways than speaking, so patients who cannot talk can often sing, then gradually shift back to speech.
• ISO principle — therapists match the music to the patient's current emotional state, then gradually shift the tempo and mood to guide them to a healthier one.