Fig. 2

a Determination of the transverse plane peak - X. Zero on the time axis marks the stimulus onset, and X was determined as the global extreme with a shorter latency to the stimulus. b Three graphs showing representative 12 epochs (4 pads × 3 current amplitudes) of the twitch protocol (vertical dotted lines separate the individual twitch epochs) from one twitch protocol of one patient. The top panel shows the stimulus trains, with black bars marking the individual train timing, duration and intensity. The middle and bottom panels show the foot angular velocities in the sagittal and transverse planes, respectively. The X and Y peaks are marked with different symbols for each twitch epoch. Blue symbols mark the movements classified as UP, green - DOWN and orange - RIGHT. c Bottom panel shows the estimated twitch points (X, Y) in a 2D coordinate system. The symbols and color-coding correspond to those from (b). The points with the highest Q factors are circled with a black line. For selected representative set epochs, none of the twitches was classified as LEFT (i.e., IV)