Hearing Loss Impacts the Temporal Patterning of Pupillary Dilation in Processing Spoken Stories

It has been well established that inserting silent pauses into normal rate and time-compressed speech improves recall and comprehension of recorded passages. However, the insertion of silent pauses does not restore recall performance equivalently across all contexts. The aim of the present experiment was to test if age-related hearing loss reduces the beneficial effect of restored processing time in extended narrative passages. Of special interest was the relationship between hearing ability and the cognitive effort deployed throughout the time course of the passage.

A group of older adults (N = 42) recruited across a range of hearing acuities were tested on their ability to listen to and recall multisentence recorded vignettes played at either a normal speech rate, time-compressed to 55% of their original playing time, or with silent pauses inserted into time-compressed vignettes (time-restoration). Pupil dilation was measured as participants listened to the passages as an index of cognitive effort.

Results demonstrated that the beneficial effect of inserted pauses into time-compressed speech was reduced for individuals with more severe hearing impairments. Measurement of pupil size revealed a general pattern in which poorer hearing was associated with larger pupillary responses at the beginning of a narrative, with this effect diminishing over the course of the narrative.

These data suggest that the magnitude of the impact of hearing acuity on the pupillary response is dependent on the time after speech onset. Results are discussed in terms of the dynamic relationship between hearing acuity, cognitive effort, and task demands.

https://doi.org/10.23641/asha.29585936.