Paul There is a fair amount of information concerning CIMT available on the Internet that is worth investigating. It is relatively easy to apply for pianists as gravity helps in immobilisation. I could start the therapy without devices to immobilise compensation simply by keeping non-participating digits at rest over the keys, and using the other hand to finger tap until the fingers could work by themselves. Other people have to use devices to 'kill off' unwanted compensatory movement. The central tenant is that the compensatory digit/digits and/or other, more subtle body movements that are partners in crime are totally excluded from therapy so that welded association is eventually broken. Over time this break becomes clean and permanent. When this happens the dystonic digit - isolated from its accomplices - experiences something akin to palsy. Continuation of more complex CIMT together with gentle introduction of suitable pieces, played at moderate tempo with a light touch that minimises tension in the larger muscles - in your case the FPL muscle - overcomes this. My later therapy included moving the thumb closer to and away from the static index on the completion of each cycle. It is at this stage that change in posture and technique reaps dividends. For example, positioning your thumb in scale passages so that it mimics thumb position when playing in 3rds.
Finally your thumb may well change shape. Mine used to be permanently hooked - like holding a pencil between the thumb and side of the hand - so much so that one specialist told me I had trigger thumb. When at rest it is now straight.
Paul
