Background and purpose: The aim of the study was to electrophysiologically examine the peripheral nervous system, mainly its autonomic part in the course of amyotrophic lateral sclerosis (ALS).
Material and methods: 19 patients with clinically definite or probable ALS were examined twice (group A and B). 20 healthy subjects were included in the study (group C). Motor conduction study (ulnar, peroneal nerve) with F wave examination, sensory conduction study (ulnar, sural nerve), EMG from 4 muscles, sympathetic skin response (SSR) and heart rate variability test at rest were performed.
Results: In the motor conduction study we revealed a significant lowering of the muscle action potential amplitude in the patient group compared with controls and its lowering in the course of ALS. F wave latencies were significantly longer in patients when compared with controls with no progression in the course of ALS. Sensory conduction parameters and heart rate variability parameters at rest did not differ significantly in groups A, B and C. SSR amplitudes were significantly lower and SSR latencies were significantly longer in the patient group in comparison with the control group. There was a significant progression of these parameters during the ALS course.
Conclusions: Loss of motor fibres creating ventral roots and sudomotor fibres lesion are the integral parts of the ALS clinical picture. They tend to worsen during the ALS course.