Investigation of the electromyographic reaction times of wrist dorsiflexion in periodic auditory stimulation

Abstract

This study investigated the effect of increased periodic counts of auditory stimuli on the changes in electromyographic reaction time (EMG-RT) and the effect of different stimulation frequencies on the changes in the EMG-RT. Twenty-one healthy subjects (16 males and 5 females; average age, 25.5 ± 5.2 years) were enrolled and provided informed consent. The conditions for auditory stimulation were as follows: 1 Hz stimulation frequency, 70 dB stimulation intensity, 1 kHz auditory frequency, and 15 stimulations per trial. The auditory stimulus was delivered via headphones. The subjects were required to raise their right wrist quickly in response to each auditory stimulus signal. The results suggest that the EMG-RT of the 2nd to 15th auditory stimuli were shorter than the EMG-RT of the first stimulus as the stimulation frequency changed. Similarly, the EMG-RT of the 3rd to 15th stimuli were shorter than that of the 2nd. There was no significant difference between the 3rd and 15th auditory stimuli EMG-RT. From these results, it can be hypothesized that the first stimulation acted as a warning signal and increased attention to the task. We think that EMG-RT was shortened compared to the stimulation frequency. This difference might be due to both the difference in histology and repetition of tasks, and the function of the central nervous system was streamlined.