Task dialogue between normal-hearing and hearing-impaired talkers in quiet and noise
Maintaining an interactive conversation requires more resources than just understanding speech. Previous studies of the timing of turn taking in conversations suggest that interlocutors have to predict the end of each other’s turn to sustain the rapid interaction that makes up normal, fluid conversation. Thus, while the presence of noise and hearing loss can make understanding speech more difficult, it should also make it more difficult to maintain the same fluid turn-taking dynamics in conversation.
In the present study, we recorded conversations between 12 pairs of native Danish young normal-hearing (NH) and older hearing-impaired (HI) listeners with mild presbyacusis in quiet and three levels of multitalker babble. The conversations involved solving the Diapix task, a spot-the-difference task between two almost identical pictures. Overall, the time the pairs took to complete the task increased with increasing noise level, suggesting that communication efficiency was impaired by the noise. Floor transfer offsets (FTOs), the intervals from when one talker stops and the other starts, were measured and the distributions were compared across conditions. With increasing background noise, both the median FTO and the standard deviation of the distribution increased. In addition, talkers held their turns significantly longer in increasing noise levels, which allows more time for speech planning and understanding. The HI’s speech rates were constant over the four conditions, whereas the NH decreased their speech rates to match that of the HI in the loudest noises.