Christoph Neuwirth1, Christian Burkhardt2, Markus Weber2. 1. Neuromuscular Diseases Centre, ALS Clinic, Kantonsspital St. Gallen, Rorschacherstrasse 95, CH-9007, St. Gallen, Switzerland. christoph.neuwirth@kssg.ch. 2. Neuromuscular Diseases Centre, ALS Clinic, Kantonsspital St. Gallen, Rorschacherstrasse 95, CH-9007, St. Gallen, Switzerland.
Abstract
INTRODUCTION: Motor unit number index (MUNIX) is a quick and feasible electrophysiological technique that estimates the number of motor neurons in limb muscles in healthy and amyotrophic lateral sclerosis (ALS) subjects. In this study we explored the feasibility, reliability, and differences of MUNIX in nasalis muscles in healthy subjects and ALS patients. METHODS: MUNIX of the nasalis muscle of 50 healthy and 20 ALS subjects with bulbar involvement was compared. Functional impairment was evaluated by the ALS Functional Rating Scale-Revised and its bulbar subscore. RESULTS: MUNIX was well tolerated and quickly performed. Bulbar ALS patients showed non-significant lower nasalis MUNIX values and a lower functional bulbar subscore. Intra- and interrater reliability showed high intraclass correlation coefficients (ICCs) in healthy subjects (0.87) and ALS patients (0.92). CONCLUSION: MUNIX of the nasalis muscle is a reproducible method, but it showed no significant difference between healthy and bulbar ALS subjects and seems not to be a useful marker of disease progression in ALS. Muscle Nerve 54: 733-737, 2016.
INTRODUCTION: Motor unit number index (MUNIX) is a quick and feasible electrophysiological technique that estimates the number of motor neurons in limb muscles in healthy and amyotrophic lateral sclerosis (ALS) subjects. In this study we explored the feasibility, reliability, and differences of MUNIX in nasalis muscles in healthy subjects and ALSpatients. METHODS: MUNIX of the nasalis muscle of 50 healthy and 20 ALS subjects with bulbar involvement was compared. Functional impairment was evaluated by the ALS Functional Rating Scale-Revised and its bulbar subscore. RESULTS: MUNIX was well tolerated and quickly performed. Bulbar ALSpatients showed non-significant lower nasalis MUNIX values and a lower functional bulbar subscore. Intra- and interrater reliability showed high intraclass correlation coefficients (ICCs) in healthy subjects (0.87) and ALSpatients (0.92). CONCLUSION: MUNIX of the nasalis muscle is a reproducible method, but it showed no significant difference between healthy and bulbar ALS subjects and seems not to be a useful marker of disease progression in ALS. Muscle Nerve 54: 733-737, 2016.