5. Neurophysiological measures correlate with functional outcomes in ALS

Abstract

Objective To identify links between neurophysiological and functional outcome measures in ALS. Methods Clinical function was assessed in 53 ALS patients (age 54 ± 10.3 years) via ALSFRS-r scale, hand grip strength and Forced Vital capacity (FVC). Compound muscle action potential (CMAP) amplitude, F-wave persistence, neurophysiological index (NI) were measured from the ulnar nerve, recording at the Abductor Digiti Minimi (ADM) muscle. Results The total ALSFRS-r scale demonstrated moderate positive correlations with CMAP amplitude (r = .354, p = .016), F-wave persistence (r = .362, p = .014) and NI (r = .431, p = .003). Measures of neurophysiological function were strongly positively correlated with the fine-motor subscale of the ALSFRS-r scale (CMAP r = .579, p .001, NI r = .579, p .001). Average grip strength showed a strong positive correlation with CMAP amplitude (r = .553, p .001), and NI (r = .570, p .001), and a moderate positive correlation with F-wave persistence (r = .300, p = .040). FVC demonstrated a moderate positive correlation with CMAP amplitude (r = .302, p = .041), and NI (r = .386, p = .008). Conclusions Neurophysiological measures correlate with functional outcomes in ALS, specifically those relating to fine-motor function. Significance Identifying links between objective neurophysiological markers and patient reported outcomes are important to assess the impact of clinical interventions.