Retraining Reaching in Cerebellar Ataxia

Damage to the cerebellum produces characteristic deficits in movement coordination, known as "ataxia." Reaching movements become curved, tremulous, and over- or undershoot targets, thus affecting nearly all activities of daily living. Sitting and standing balance becomes unsteady, and walking has a characteristic 'drunken' appearance with lateral veering and a widening of the base of support. People with many types of neurological diseases (e.g. autosomal dominant ataxias (e.g. SCAs), multiple sclerosis, cerebral palsy, stroke, Freidreich's ataxia) often have disabling ataxia.

In past work the investigators have shown that many individuals with ataxia from cerebellar disease can learn simple visuomotor tasks using reinforcement learning paradigms. The investigators do not know if individuals with ataxia from cerebellar disease can improve more complex motor patterns. In general, there are few rehabilitation studies on ataxia, with most focusing on balance and walking. Yet, arm ataxia is a significant problem that affects most all activities of daily living (e.g. eating, cooking, bathing, dressing, working). Many studies have assessed reaching ataxia on single days in order to try to better understand the fundamental basis for ataxic arm movements. Based on previous literary searches, there are only a couple of small studies that have tested whether training over weeks can mitigate arm ataxia. Each of these was a case series of either 3 or 4 people, and all patients had ataxia from lesions that included structures outside of the cerebellum. Both showed some positive effects but responses varied across patients. This work that the investigators propose will look at the affects of a longer training regimen of upper limb reaching in people with cerebellar ataxia.

The investigators will study cerebellar patients that have shown the ability to learn from previous work. Subjects with cerebellar ataxia will be randomized into two groups to receive either reinforcement training or standard practice training over a 12 week period. Subjects will train for 45 minutes a day, 3 times per week for two weeks for each type of training, with a two week 'rest' period in between. After training, subjects will be asked to return for two visits to test for retention. On each training day, reinforcement training (or standard practice) will be done using an Oculus Rift and Touch 3D headset. Training encompasses reaching to a 3D target with either online visual feedback or binary feedback 400 times. Motion tracking sensors will be placed on the shoulder, elbow, wrist, and finger, in order to track movement data in real time. These studies will provide important new information about upper limb long term training with visual feedback in individuals with Cerebellar Ataxia

Inclusion criteria

• Cerebellar damage from stroke, tumor or degeneration
• Age 22-80

Exclusion criteria

• Clinical or MRI evidence of damage to extracerebellar brain (e.g. multiple system atrophy)
• Extrapyramidal symptoms, peripheral vestibular loss, or sensory neuropathy
• Dementia ( Mini-Mental State exam > 22)
• Pain that interferes with the tasks
• Vision loss that interferes with the tasks