Motor sequence awareness is impaired in dystonia despite normal performance.

OBJECTIVE

Dystonia is a movement disorder that has been associated with impaired motor learning and sequence recognition. However, despite evidence that patients with dystonia have a reduced sense of agency, it is unclear whether dystonia is specifically associated with impaired recognition of a movement sequence. We have shown previously that performance consistency in the temporal and kinematic domains predicts awareness of underlying motor patterns in a finger-tapping task. Since movements in dystonia are characterized by high variability, we predicted that subjects with dystonia would have decreased motor sequence awareness.

METHODS

Subjects with dystonia (n = 20) and healthy control adults (n = 30) performed finger-tapping sequences with a common motor pattern and changing stimulus-to-response mappings. Subjects were said to be "aware" of the motor pattern if they recognized that their fingers moved in the same order during each stimulus-to-response remapping.

RESULTS

Subjects with dystonia had decreased motor pattern awareness, but those differences were not due to greater performance variability. Subjects with dystonia tapped sequences as series of discrete movements, rather than as a combined series.

INTERPRETATION

Dystonia is associated with impaired recognition of a repeating movement pattern. This difference may result from a strategy of separating sequential elements and attending to them individually. Ann Neurol 2018;83:52-60.