The diagnosis of amyotrophic lateral sclerosis (ALS) remains problematic, with current diagnostic criteria (revised El Escorial [rEEC] and Awaji) being complex and prone to error. Consequently, the diagnostic utility of the recently proposed Gold Coast criteria was determined in ALS. Methods: We retrospectively reviewed 506 patients (302 males, 204 females) to compare the diagnostic accuracy of the Gold Coast criteria to that of the Awaji and rEEC criteria (defined by the proportion of patients categorized as definite, probable, or possible ALS) in accordance with standards of reporting of diagnostic accuracy criteria. Results: The sensitivity of Gold Coast criteria (92%, 95% confidence interval [CI] = 88.7-94.6%) was comparable to that of Awaji (90.3%, 95% CI = 86.69-93.2%) and rEEC (88.6, 95% CI = 84.8-91.7%) criteria. Additionally, the Gold Coast criteria sensitivity was maintained across different subgroups, defined by site of onset, disease duration, and functional disability. In atypical ALS phenotypes, the Gold Coast criteria exhibited greater sensitivity and specificity. Interpretation: The present study established the diagnostic utility of the Gold Coast criteria in ALS, with benefits evident in bulbar and limb onset disease patients, as well as atypical phenotypes. The Gold Coast criteria should be considered in clinical practice and therapeutic trials.

IntroductionWe sought to evaluate the reproducibility of the motor unit number index (MUNIX) and MScanFit motor unit number estimation (MScan) when recording was performed over intrinsic hand muscles.MethodsThe compound muscle action potential (CMAP) amplitude, MUNIX, and MScan were measured from the abductor pollicis brevis (APB), first dorsal interosseous (FDI), and abductor digit minimi (ADM) muscles from 15 healthy volunteers on three different occasions.ResultsThe reproducibility of CMAP amplitudes was excellent, with intraclass correlation coefficients (ICC) of 0.86 (APB), 0.90 (FDI), and 0.96 (ADM). Motor unit number index (ICCAPB 0.73, ICCFDI 0.85, ICCADM 0.85) and MScan (ICCAPB 0.86, ICCFDI 0.83, ICCADM 0.81) were highly reproducible across the three muscles. There were no significant correlations between MUNIX and MScan coefficients of variation (CV) and CMAP amplitude CVs.DiscussionReproducibility of MUNIX and MScan was not significantly different across the intrinsic hand muscles and was independent of CMAP amplitude variability.

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