Long-term motor learning in focal hand dystonia

•Focal hand dystonia (FHD) usually occurs in the over-learned stage.•To know long-term motor learning characteristics and underlying pathophysiological features possibly predisposing to dystonia.•FHD have motor learning capacity comparable to healthy volunteers and do not show pathophysiological abnormalities. 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. 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. 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. Over 12 weeks, FHD have motor learning capacity comparable to HVs and do not show pathophysiological abnormalities. Further studies would be valuable with more patients, more extended periods of practice, and more detailed electrophysiological explorations.