Dystonia is a neurological movement disorder characterized by sustained or intermittent muscle contractions causing unwanted involuntary movements. The disorder may be focal (affecting one body region) or more generalized;it is likely that the two entities have different etiologies. Focal hand dystonia (FHD) is characterized by involuntary muscle contractions in the fingers and hand. It has increased incidence in instrumental musicians, and, when it occurs in the professional, is usually career ending. Musicians with FHD demonstrate deficiencies in motor learning and an under-activation of brain structures associated with automatic motor control. Motor sequence learning and performance is generally thought to be either under cognitive or automatic control;cognitive control requires attention directed to the motor movements while automatic performance allows freedom for executive function. When playing an instrument, musicians require both cognitive and automatic control over finger movements, so exquisite performance likely takes place at the interface of these two control mechanisms. This project will investigate the role of automatic and cognitive control in FHD. The overall hypothesis is that FHD results from impaired neural circuitry at the interface between cognitive and automatic control of a specific over-learned task. Furthermore, this interface is likely to be less affected in non-focal forms of dystonia. Musicians with FHD, age-matched musicians without dystonia, non-musicians with non-focal dystonia that involve the hand, and non-musicians without dystonia will perform a battery of sequential finger-tapping tasks while wearing an instrumented glove to record detailed movement kinematics. The tasks will probe the variables that differ between cognitive and automatic control: tapping speed, retention, and explicit knowledge of underlying sequence patterns. The results will provide important information about the neural circuitry responsible for loss of motor control in musicians with FHD. Of immediate practical importance, the results of this project will determine whether a cognitive strategy-based therapy may provide benefit for musicians with FHD. Future studies will involve application of these findings to protective learning strategies in the context of skil learning requiring high repetition.
Instrumental musicians are at risk for developing focal hand dystonia, a career-ending neurological disorder where the fingers involuntary flex or extend while playing the instrument. There are many details involved in skilled musical performance. A professional musician has to decide on an ongoing basis which details require attention and which details can be performed automatically without thinking about the movements. The immediate goal of this project is to determine whether this balance between conscious control and automatic control is impaired in focal hand dystonia in musicians, and whether a learning-based therapy may be a treatment option for this disorder.