Long-term motor learning in focal hand dystonia

Abstract

Objective: Because focal hand dystonia usually occurs in the over-learned stage, it would be valuable to know long-term motor learning characteristics and underlying pathophysiological features that might predispose to dystonia.

Methods: We conducted a case-control exploratory study of 15 visits over 12 weeks in the non-affected hand of a 4-finger sequence of 8 key presses in eight patients with FHD compared with eight age- and sex-matched, healthy volunteers (HVs). We studied the behavioral data and the physiological changes of the brain, including motor cortical excitability and cortical oscillations.

Results: There was no significant difference in the time to reach 100 % accuracy between FHD and HV during the 80-day follow-up period. There was a statistically significant difference in the accuracy of sequential finger movement tasks between patients with FHD compared with HVs over 12 weeks, but post-hoc analysis with multiple comparion correction did not show difference. There were no significant differences in recruitment curve changes and task-related power changes of alpha and beta bands.

Conclusion: Over 12 weeks, FHD have motor learning capacity comparable to HVs and do not show pathophysiological abnormalities.

Significance: Further studies would be valuable with more patients, more extended periods of practice, and more detailed electrophysiological explorations.

Keywords: Electroencephalography; Focal hand dystonia; Long-term; Motor learning; Transcranial magnetic stimulation; Writer’s cramp.