Non-invasive fasciculation assessment of gastrocnemius failed to show diagnostic or prognostic utility in ALS

ObjectivesAmyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder, affecting both upper and lower motor neurons. High-density surface electromyography is a non-invasive measure of muscle fasciculations, a phenomenon prevalent early in the disease. Previous studies highlighted the clinical importance of these measures from the biceps brachii muscle. Our study aimed to investigate the diagnostic and prognostic value of the medial gastrocnemius muscle. MethodsWe performed a retrospective study of 49 ALS and 25 control participants. Means comparisons, logistic regression, receiver operating characteristic analysis, Kaplan-Meier analysis, and a multilevel Cox model were used to determine the predictive utility of fasciculation potential (FP) parameters including FP frequency, median amplitude, and amplitude dispersion. ResultsFP parameters demonstrated a poor ability to differentiate between ALS and controls, with ROC analysis producing areas under the curve between 0.58 and 0.63. Furthermore, there was no association between FP parameters and ALS prognosis in the Cox model. ConclusionsFP parameters from the medial gastrocnemius muscle are not useful for the diagnosis or prognosis of ALS patients. SignificanceOur results highlight the poor clinical utility of fasciculation quantification in the medial gastrocnemius muscle. Future studies should focus on recordings from more clinically relevant muscles earlier in the disease. HighlightsO_LIFasciculation parameters from the medial gastrocnemius muscle have poor ability to differentiate ALS patients from controls. C_LIO_LIFasciculation parameters from the medial gastrocnemius muscle cannot reliably predict the prognosis of ALS patients. C_LIO_LIFuture studies should measure more clinically relevant muscles at an earlier stage in the disease course over a protracted period. C_LI