We have developed a novel electronic musical instrument with a pre-programmed score, called Cymis, to help the disabled enjoy playing musical pieces. In 2008, eld experiments commenced at a nursing home (capacity 52 clients; average age 58.6; cerebral palsy 32 clients). The purpose of the present study was to demonstrate that Cymis is useful and effective for helping the severely disabled maintain or improve their quality of life. First, the accessibility of Cymis was revealed by the fact that 34 clients (63%) played Cymis for an average of 5.6 years. Second, each client s progress in performance, which possibly re ects improvements of upper-limb motor control function, was examined for the longest duration of over 7 years. Among 31 clients, 13 (42%) showed progress, 17 (55%) showed no change (5 of whom showed progress initially but then regressed to their original status), and 1 (3%) revealed deterioration in condition. Third, psychological effects were measured using an original Face Scale before and after playing Cymis, for a total of 395 performances by 38 clients. Clients became happier in 208 performances (53%), showed no changes in 139 (35%), and became sadder in 48 (12%). Finally, with respect to their care plans, 19 of 52 clients (37%) selected Cymis in 2015, and this number itself implies the importance of Cymis. Basic reasons for selection were investigated by care workers assessments from mental and psychological perspectives. In conclusion, Cymis was useful, effective, and attractive to the disabled; it permitted them to enjoy playing music that might not otherwise be possible, and some evidence of therapeutic effect was found.