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.

Temporal and kinematic consistency predict sequence awareness.

Many human motor skills can be represented as a hierarchical series of movement patterns. Awareness of underlying patterns can improve performance and decrease cognitive load. Subjects (n = 30) tapped a finger sequence with changing stimulus-to-response mapping and a common movement sequence. Thirteen subjects (43 %) became aware that they were tapping a familiar movement sequence during the experiment. Subjects who became aware of the underlying motor pattern tapped with greater kinematic and temporal consistency from task onset, but consistency was not sufficient for awareness. We found no effect of age, musical experience, tapping evenness, or inter-key-interval on awareness of the pattern in the motor response. We propose that temporal or kinematic consistency reinforces a pattern representation, but cognitive engagement with the contents of the sequence is necessary to bring the pattern to conscious awareness. These findings predict benefit for movement strategies that limit temporal and kinematic variability during motor learning.