The purpose of this study was to compare and contrast within and between participant performance on three different measures of listening effort: a dual-task paradigm, pupillometry, and skin conductance; participants also subjectively rated the difficulty of their experience. A repeated measures design was used to address the reliability and validity of each measure. 20 participants were recruited and attended two sessions; the second occurred a minimum of one week after the first. Participants listened to sentences presented in stationary noise at four different signal-to-noise ratios: quiet, 0, -3, and -5 dB SNR. The variables of interest were: change in peak-to-peak pupil diameter, change in reaction time from baseline, skin conductance response amplitude, and skin conductance response quantity.
The results indicated that as SNR decreased, speech perception performance decreased and subjective listening effort increased. Participants accurately and consistently rated the more difficult conditions as requiring more listening effort. The change in reaction time from baseline, peak-to-peak pupil diameter, and skin conductance response quantity increased as SNR decreased; skin conductance response amplitude did not vary as task difficulty increased, but skin conductance response amplitude was larger for incorrect responses than it was for correct responses. There was a significant practice effect observed for the reaction time data. The dual-task paradigm and pupillometry measures had the greatest reliability and validity. This study demonstrated that listening effort can successfully be quantified both subjectively and objectively by using a variety of tasks. Future studies may be able to use these measures to further assess listening effort in the clinic and in the real-world.