Abnormal sensorimotor processing in pianists with focal dystonia.
Focal dystonia is a task-specific sensorimotor disorder that is characterized by sustained muscle contractions, which may cause twisting, repetitive movements, or abnormal postures. In the current study, the contingent negative variation was recorded in a group of professional pianists with focal dystonia (musicians' cramp) and compared to pianist controls. The CNV is composed of an early stimulus processing component and a later response preparation component. The CNV can be elicited in tasks that require movement and nonmovement. A subtractive analysis with a nonmovement condition was used to minimize effects of the CNV not related to response preparation. The current results revealed no group differences for the early CNV (processing of stimulus properties). In contrast, a significant group difference was found in the late CNV (movement preparation) between patients and controls, with the patients showing significantly higher activation prior to movement. The current study demonstrates an increase in overall sensorimotor activity prior to movement in patients with musicians' cramp. This overexcitation of the cortex may be the result of a dysfunction in the globus pallidus, resulting in a lack of inhibition and/or an increase in excitation.
D000328:Adult; D000368:Aged; D001931:Brain Mapping; D003265:Contingent Negative Variation / Q000502:physiology; D020821:Dystonic Disorders / Q000503:physiopathology*; D004569:Electroencephalography / Q000295:instrumentation / Q000379:methods; D004576:Electromyography / Q000295:instrumentation / Q000379:methods; D006801:Humans; D008297:Male; D008875:Middle Aged; D009068:Movement / Q000502:physiology; D009069:Movement Disorders / Q000503:physiopathology; D009146:Music; D010812:Physical Stimulation; D011930:Reaction Time; D013003:Somatosensory Cortex / Q000002:abnormalities*