Figure 1
From: Slowed Movement Stopping in Parkinson’s Disease and Focal Dystonia is Improved by Standard Treatment
Validity and reliability of optimum combination stop signal reaction time (ocSSRT) compared to average stop signal reaction time (avSSRT). (A) Scatter plot showing association between avSSRT and ocSSRT. The intra-class correlation coefficient (ICC) of ocSSRT and avSSRT in 20 healthy volunteers was 0.79 (p = 0.001). The line of best fit (dotted line) shows a linear relationship between two measures. (B) Box and whisker plot compares the median difference and inter-quartile range (IQR, a measure of dispersion) of ocSSRT and avSSRT between two sets (baseline test and retest) of stop signal tasks (with an interval of one month) completed in 14 healthy individuals. The graph shows that test-retest difference of ocSSRT was significantly lower than avSSRT (Wilcoxon signed ranks test, p = 0.048). The dispersion of test-retest difference was significantly more for avSSRT (Fligner-Killeen test; p = 0.009). There is therefore an increased variability and reduced precision of avSSRT compared to ocSSRT.
