Abstracts of the 8th Meeting of the Italian Peripheral Nerve Study Group: 7

Abstract

The pathological hallmark of amyotrophic lateral sclerosis (ALS) is the progressive death of upper and lower motor neurons, leading to a clinical pictures mainly characterized by weakness, muscle wasting, brisk reflexes and Babinski sign. Routine electromyographic and electroneurographic studies are mandatory to a correct diagnosis but are unable to precisely quantify the pathological changes in the motor unit. Motor unit number estimation (MUNE) is a recent neurophysiological technique that allows to estimate number and amplitude of motor units in single muscles in order to assess the severity of ALS and to follow‐up the progression of the disease. We applied this technique in 15 patients (12 male and 3 female; mean age ± SD: 65.7 ± 9.5 yrs, range 45–82), affected by definite or probable ALS according to El Escorial Criteria, and in 11 healthy subjects (4 male and 7 female; mean age ± SD: 63.7 ± 8.2 yrs, range 50–76), in order to assess changes in motor unit features of abductor digiti minimi (ADM) and tibialis anterior (TA) muscles. We found a significant difference (p < 0.05) in the mean number of motor units between the two groups: 75 in ADM and 51,8 in TA in the ALS cohort vs. 283,5 in ADM and 96,9 in the healthy subjects. Conversely, the differences in the mean and maximal area between the two groups did not reach the statistical significance (ALS patients: max area 34.7 mVms, mean area 1.9 mVms; healthy subjects: max area 18.2 mVms, mean area 0.9 mVms). Our preliminary results confirm that MUNE is able to quantify the pathological changes in motor unit parameter and represents an adequate follow‐up tool for disease progression and effectiveness of pharmacological treatment.