Fully intact contact heat evoked potentials in patients with amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is typically considered to be a disease of motor, not sensory, neurons. However, reports exist of sensory system involvement in ALS. In this study we aimed to study the characteristic of contact heat-evoked potentials (CHEPs) in patients with ALS and to evaluate the nociceptive pathway in these patients. Sixty patients with ALS and 60 controls had pain elicited by a CHEP stimulator with an accelerated velocity of 70 degrees C/s. Thermal stimuli were sent at 54.5 degrees C to three body sites: the dorsum of the hand, the proximal volar forearm, and the skin near C7. CHEPs were recorded from Cz and Pz. The onset negative peak latencies were 561.2 +/- 28.6 ms, 540.1 +/- 39.2 ms, and 502.4 +/- 26.2 ms when the dorsum of the hand, the proximal volar forearm, and skin near C7 were stimulated, respectively. There were no significant differences between the ALS patients and the controls with CHEP (P > 0.05). Our results suggest that the nociceptive pathway is intact and support the idea that small fibers and their sensory pathway are spared in ALS.