The effects of noise on objective and subjective measures during speech recognition tasks as stress indicators: preliminary results

Objective indicators of stress associated with annoyance scales are essential tools to advance knowledge in the area. Electrodermal activity (EDA) can be used to evaluate physiological responses, providing a picture of autonomic nervous system. Twenty-five adults were evaluated at three situations of speech recognition tasks with monosyllables: in quiet, competitive noise at 65 dBA and 75 dBA. After each situation with noise, the annoyance scale was applied. After, low-pass filtering was used, and phasic phase was analyzed. Results showed that the percentage of speech recognition hits decreased significantly with noise at 75 dBA (p<0.01), when compared to the situation without noise. Furthermore, it was found that annoyance increased significantly as noise at 75 dBA (p<0.01), when compared to 65 dBA. In relation to EDA, there was a significant increase in the number of peaks when comparing speech recognition situations without noise and with noise at 75 dBA (p<0.01), but not for noise at 65 dBA. Regarding the amplitude of the first skin conductance response peak, there was no significant difference between the three situations. These findings suggest that higher noise levels impact on speech recognition and annoyance, causing greater listening effort and increasing stress levels.