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. 2021 Jan 29;12:625144. doi: 10.3389/fneur.2021.625144

Figure 2.

Figure 2

Motor nerve conduction studies of patient 1 (A,B) compared to a healthy control subject (C,D). Amplitude and duration of the negative phase of compound muscle action potentials (CMAPs) were measured at a sensitivity of 0.5 mV with a 2 Hz low frequency filter. The cut-off values for distal CMAP duration are according to reported normal values + 2 SD (12). (A) median nerve: distal CMAP amplitude is reduced (4.2 mV), distal motor latency (DML) is normal (3.9 ms), distal CMAP duration is increased (9.3 ms, 127% of upper limit of normal = 7.3 ms), conduction velocity (CV) is 48 m/s. CMAP amplitude and duration did not change between proximal and distal stimulation. Note the broadening and smooth contour of the negative phase of the distal CMAP and the reduction of the ensuing positive phase compared to panel (C) (CMAP duration = 5.7 ms); (B) ulnar nerve: distal CMAP amplitude is slightly reduced (5.7 mV), DML is normal (2.9 ms), distal CMAP duration is increased (13.7 ms, 183% upper limit of normal = 7.5 ms), CV is 55 m/s. CMAP amplitude and duration did not change with proximal stimulation. Note the very prolonged negative phase of the distal CMAP with a long tail and the absence of the ensuing positive phase compared to panel (D) (CMAP duration = 6.3 ms).