Table 2.

N9 and N20 characteristics

	Median		Ulnar
	Controls	ALS	Controls	ALS
N9
Latency	10.7±0.2	10.8±0.2	11.4±0.2	11.3±0.2
CVp	65.9±0.9	66.6±0.7	62.1±0.9	63.5±1.1
Amplitude	6.1±0.5	5.1±0.5	5.3±0.8	4.2±0.4
N20
Latency	19.0±0.4	19.5±0.3	19.2±0.3	19.6±0.3
CVc	31.5±1.2	28.3±1.0*	33.4±1.4	30.3±1.2
Amplitude	7.4±0.2	7.2±0.2	7.4±0.2	7.0±0.2

Latency: mean peak latency (ms±1 SEM) of N9 recorded at the Erb point, and of N20 recorded at the level of primary somatosensory cortex (S1) for median and ulnar nerves, in controls and patients with amyotrophic lateral sclerosis. CVp: peripheral conduction velocity (m/s±1 SEM) according to N9 peak latency and the distance between stimulation site and C7 vertebra. CVc: central conduction velocity (m/s±1 SEM) according to the difference between N20 and N9 peak latencies and the distance between C7 vertebra and recording site, in front of S1. Amplitude: peak-to-peak amplitude of N9 and peak amplitude of N20 (μV).

*p<0.05.