Piano playing in Alzheimer's disease: Longitudinal study of a single case

Preserved musical performance by patients with Alzheimer's disease (AD) has been attributed to an intact system for implicit musical cognition which may be localized in the right hemisphere. To examine this idea more thoroughly, we studied patient ML, a woman with AD who learned to play the piano as a child. Over three yearly evaluations, ML exhibited progressive deterioration in the following domains: language, visuospatial functions, attention, sequencing, picture priming, recognition of familiar songs, and discrimination of rhythm, meter, transposition, and major from minor keys, but pursuit rotor learning remained intact. By the third year of testing, ML also exhibited severe limb apraxia, but showed only subtle losses in the quality of her piano playing of familiar songs. She also showed immediate and accurate transfer of her playing skill from the piano to the xylophone. Preserved musical performance in AD seems to depend on circuits involving the basal ganglia, cerebellum and motor areas of the thalamus and cerebral cortex that remain relatively intact until the late stages of the disease, but there is no evidence that the right hemisphere plays a special role in this phenomenon.