Prospective Study on the Efficiency of Neurophysiological Index Applicated at Posterior Tibial Nerve/Abductor Pollicis Longus in Patients With Amyotrophic Lateral Sclerosis

ABSTRACT

BACKGROUND: Neurophysiological Index (NI) is a sensitive measure of changes during the course of amyotrophic lateral sclerosis (ALS). However, NI applied at the ulnar nerve has limitation in that the initial manifestation of ALS is different among individual patients. This study was aimed to evaluate the efficiency of NI applied to the posterior tibial nerve system in a prospective study of progression in ALS patients. METHODS: The subjects of the study were 22 patients with definite or probable ALS based on revised EL Escorial criteria. NI applied to the ulnar nerve/abductor digiti minimi muscle and the posterior tibial nerve/abductor hallucis muslce, revised ALS functional rating scale, Norris scale, and grip power were obtained at four and eight months of the follow-up. RESULTS: Overall, NI at both ulnar and posterior tibial nerve systems showed a significant interval change at 4 and 8 months. Although NI in both nerve systems showed significant changes at an interval of 4 months in patients with upper limb onset, NI obtained from the ulnar nerve did not show a difference from the baseline in the lower limb onset patients. Moreover, there was a significant change of NI in the early stage ALS patients, compared to the late stage patients. CONCLUSIONS: In the lower limb onset patients, NI obtained from the posterior tibial nerve is more useful in evaluating the disease progression pattern. Moreover, NI is more effective in the evaluation of the patients in the early stage.