Somatosensory Processing in Focal Hand Dystonia

Patients with focal dystonia experience uncontrollable movements of the hand during certain types of skilled movements. Though the origin of the disorder is not fully understood, it is thought that brain areas involved in moving the hands and receiving touch information from the hands, are involved. For example, patients with dystonia affecting the hand show changes in their ability to perceive touch - this is something that typically escapes the patients own awareness. Further, the area of the brain receiving touch information has a disrupted representation of the finger skin surfaces.

The goal of our research is to improve dystonia symptoms in patients with hand dystonia. We will attempt to achieve this goal by implementing an intensive training treatment that requires patients to attend to, and use touch information applied to specific fingertips. Previous work has attempted to alter touch perception using sensory training and improvements in motor control (hand writing) of dystonia patients were observed. For example, learning to read Braille improves tactile perception and handwriting in focal hand dystonia. A different approach to treat focal hand dystonia involves a technique called repetitive transcranial magnetic stimulation (rTMS), and this can also temporarily improve hand writing in dystonia patients. The proposed research will attempt to alter touch processing using touch training alone, or in combination with rTMS. Rather than train using Braille reading, the sensory training will be applied using a systematic, experimenter controlled stimulus set that focuses on touch stimuli applied to individual digits. Importantly patients will have to associate certain types of touch information with rewards and other touch input with the lack of a reward.