Intra- and inter-rater reliability and agreement of stimulus electrodiagnostic tests in post-COVID-19 patients

Background. COVID-19 patients may present sequelae, such as neuromuscular electrophysiological disorders (NED), that can be assessed using the stimulus electrodiagnostic test (SET). However, little is known about the reliability and agreement of the SET in post-COVID-19 patients. Objective. We aimed to verify the intra–inter-rater reliability and agreement of SET measurements in the rectus femoris, vastus medialis, vastus lateralis, tibialis anterior, and gastrocnemius lateralis (GL) in post-COVID-19 participants. Methods. We designed an observational prospective study to evaluate 20 (10 males and 10 females) post-COVID-19 patients, age: 44.95 ± 11.07 years, weight: 87.99 ± 19.08 kg, height: 1.69 ± 0.09 m. Two independent raters took two evaluations using the SET on selected muscles. The intra-class correlation coefficient (ICC) and 95% limits of the agreement defined the quality and magnitude of the measures. Results. For intra-rater reliability, all measurements presented correlations classified as high or very high (ICC: 0.71–1.0). For inter-rater reliability, the rheobase, chronaxie, accommodation, and accommodation index presented high or very high correlations, except for the accommodation index of the GL (ICC = 0.65), which was moderate. Conclusion. The reliability of the SET obtained by independent raters was very high, except for the GL accommodation, which presented moderate ICC. Therefore, the SET is a reliable tool for evaluating NED in post-COVID-19 patients.