Video Game-based Therapy for Arm Weakness In Progressive Multiple Sclerosis

Participants will receive intensive therapy through a video game in their own homes for 1 month. The game is operated by movements of the body (no controller needed) and acts like a virtual therapist. Participants will agree to play the game for 30 hours. They will also receive 4 home visits from a therapist designed to increase use of their arm for daily activities that are important to them. Participants will also receive a smart watch that will measure use of their weaker arm and alert them when their arm is not participating in activities. Arm strength and function will be measured before and after the therapy program.