Neurophysiologic studies and survival in amyotrophic lateral sclerosis

Abstract

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease. Neurophysiology techniques support the diagnosis. Evaluate the relationship between nerve conduction studies (NCS)/EMG and survival of ALS patients. 15 consecutive cases of ALS fulfilling El Escorial-Awaji Shima criteria in the Instituto Nacional de Nutrición Salvador Zubirán at Mexico City, from 2016 to 2019. Other etiologies were excluded with laboratorial and imaging studies. We collected informed consent, clinico-epidemiological data and performed a standard NCS/EMG to each patient, the relationship between NCS/EMG parameters and survival was evaluated by Spearman and Pearson correlation in SPSS® version 25 software. 10 male, mean age was 57.7 ± 13.1 years. The gap between symptoms onset and diagnosis was 12.8±16 months; cervical was the most common first presentation, 4 patients (26.7%) were diabetics; normal findings on MRI was found in 80%. NCS showed that the most affected nerves were: median (distal latency (DL) averages: 3.85 m/s, Compound muscle action potential (CMAP) amplitudes: 2.97 μV, conduction velocities (CV): 43.3 m/s. Ulnar nerves: DL: 3.32 m/s, CMAP amplitudes: 3.98 μV, CV: 50.37 m/s) (Table 1). F waves latencies were found abnormal in 4/15 patients in median, cubital and peroneal nerves; sensory affection was found in 4/15 patients in peroneal and sural nerves. EMG revealed denervation changes, poor recruitment in all the studied muscles including paraspinals; the muscle unit action potentials (MUAP) parameters showed reinnervation changes (Table 2). We found a bilateral good correlation between tongue MUAP duration (p = 0.047) and months of life. NCS showed predominantly an axonal damage in the studied nerves. Tongue MUAP's duration was correlated with a shorter survival time (Graph 1).