Inclusion Criteria1. Damage to the following areas of the brain, all of which may be involved in coordination of reach to grasp confirmed by CT scan: parietal, cerebellar, internal capsule and basal ganglia,
2. A score of 6 or more on the arm section of the Rivermead Motor Assessment (able to reach and pick up a tennis ball and release on thigh),
3. Time between start of hand opening and start of hand transport > 60 ms (measured with GRASP).
Exclusion Criteria1. Cognitive dysfunction which prevents understanding of the task,
2. Severe concurrent medical problems that prevent repetitive reaching (including shoulder pain),
3. A diagnosis of Parkinson's disease, or
4. Lack of informed consent.