62 CHAPTER 3 Supplementary Materials Normalized error rates Efficiency analysis To control for any potential group differences in speed-accuracy trade-off during the task, we additionally calculated the efficiency scores for each condition (i.e. divided the normalized error rates by the median reaction times). We performed a 3-factor mixed ANOVA with between-group factor GROUP (neuralgic amyotrophy patients, healthy control subjects) and repeated factors LATERALITY (left, right), ROTATION (-135, -105, -75, -45, 45, 75, 105, 135 degrees) for efficiency scores, as supplementary analyses (see Supplementary Table 1). The interaction between GROUP and LATERALITY remained significant when correcting error rates for reaction times by running the same analysis on efficiency scores confirming that group differences in speed-accuracy trade-off did not influence our results. Supplementary Figure 1 Normalized error rates These graphs show the normalized error rates for the different rotations for unaffected nondominant left A. and affected dominant right B. hands for factors LATERALITY, ROTATION and GROUP. In panel C. the data have been collapsed across ROTATION, to illustrate the LATERALITY x GROUP interaction and the between- and within-group differences. Individual data points are provided. NA = neuralgic amyotrophy patients; HC = healthy controls; a.u. = arbitrary units. Error bars ± 1 standard error. * significant difference at p < 0.01. Supplementary Table 1