Análise da fadiga muscular em membros superiores de pessoas com ELA submetidas à intervenção com HD-tDCS: relato de dois casos

Abstract

It is known that individuals with amyotrophic lateral sclerosis (ALS) exhibit an imbalance in the excitatory and inhibitory mechanisms of the cortical motor circuits, which may be associated with muscle fatigue, a highly prevalent and disabling symptom. This study aims to analyze the effects of High-Definition Transcranial Direct Current Stimulation (HD-tDCS) on muscle fatigue in two individuals with ALS. The participants underwent an intervention that combined HD-tDCS with the performance of functional activities for five consecutive days. Each session lasted 20 minutes. Fatigue was assessed using the Fatigue Severity Scale and surface electromyography, with values of root mean square (RMS), mean frequency (MNF), and continuous wavelet transform. Both participants showed a reduction in the Fatigue Severity Scale scores compared to the initial evaluation and follow-up. Electromyographic assessment evidenced the presence of muscle fatigue in both participants in the week before the intervention, after the intervention, and in the follow-up evaluation (the second week after the intervention conclusion). Participant 1 showed a reduction in fatigue for the activity of opening a bottle bilaterally; Participant 2 showed a reduction in fatigue in the elbow flexion movement bilaterally and in pointing with the right upper limb. The results indicate a reduction in the level of fatigue following the application of HD-tDCS; however, such results should not be generalized as they are case reports. Therefore, the need for more studies in this line of research is evident to better understand the effects of HD-tDCS on muscle fatigue in individuals with ALS.