Table 2.

Nerves examined with NCS and frequency of fulfillment of the electrodiagnostic demyelination criteria.

Nerve	Of 203 patients	%	% positive
			Any criterion	I‐A	I‐B	I‐C	I‐D	I‐E	I‐F	I‐G	II
Median	183	90.1	39.5	n.a.	13.0	7.7	4.8	7.7	4.3	20.2	6.3
Ulnar	115	56.7	38.5	11.8	10.3	6.6	4.4	8.1	3.7	19.9	5.9
Tibial	199	98.0	51.7	16.4	7.4	1.5	8.0	13.9	31.8	10.9	n.a.
Peroneal	27	13.3	34.1	11.8	5.9	0.0	11.8	5.9	8.8	8.8	2.9

Criteria as defined by EFNS/PNS ⁵ : I‐A: Motor distal latency prolongation ≥50% above ULN. I‐B: Reduction of motor conduction velocity ≥30% below LLN. I‐C: Prolongation of F‐wave latency ≥30% above ULN (≥50% if amplitude of distal negative peak CMAP <80% of LLN values). I‐D: Absence of F‐waves if the nerve has a distal negative peak CMAP amplitudes ≥20% of LLN. I‐E: Partial motor conduction block: ≥50% amplitude reduction of the proximal negative peak CMAP relative to distal, if distal negative peak CMAP ≥20% of LLN. I‐F: Abnormal temporal dispersion (>30% duration increase between the proximal and distal negative peak CMAP). I‐G: Distal CMAP duration (interval between onset of the first negative peak and return to baseline of the last negative peak) increase (median ≥6.6 msec, ulnar ≥6.7 msec, peroneal ≥7.6 msec, and tibial ≥8.8 msec). II: ≥30% amplitude reduction of the proximal negative peak CMAP relative to distal, excluding the posterior tibial nerve, if distal negative peak CMAP ≥20% of LLN.

NCS, nerve conduction studies; ULN, upper limit of normal; LLN, lower limit of normal; CMAP, compound muscle action potential.