How cognition might influence hearing aid-design, fitting, and outcomes

Native and Non-native Speech Perception by Hearing-Impaired Listeners in Noise- and Speech Maskers

This study evaluated how hearing-impaired listeners perceive native (Swedish) and nonnative (English) speech in the presence of noise- and speech maskers. Speech reception thresholds were measured for four different masker types for each target language. The maskers consisted of stationary and fluctuating noise and two-talker babble in Swedish and English. Twenty-three hearing-impaired native Swedish listeners participated, aged between 28 and 65 years. The participants also performed cognitive tests of working memory capacity in Swedish and English, nonverbal reasoning, and an English proficiency test. Results indicated that the speech maskers were more interfering than the noise maskers in both target languages. The larger need for phonetic and semantic cues in a nonnative language makes a stationary masker relatively more challenging than a fluctuating-noise masker. Better hearing acuity (pure tone average) was associated with better perception of the target speech in Swedish, and better English proficiency was associated with better speech perception in English. Larger working memory and better pure tone averages were related to the better perception of speech masked with fluctuating noise in the nonnative language. This suggests that both are relevant in highly taxing conditions. A large variance in performance between the listeners was observed, especially for speech perception in the nonnative language.

Cognitive spare capacity and speech communication: a narrative overview

Background noise can make speech communication tiring and cognitively taxing, especially for individuals with hearing impairment. It is now well established that better working memory capacity is associated with better ability to understand speech under adverse conditions as well as better ability to benefit from the advanced signal processing in modern hearing aids. Recent work has shown that although such processing cannot overcome hearing handicap, it can increase cognitive spare capacity, that is, the ability to engage in higher level processing of speech. This paper surveys recent work on cognitive spare capacity and suggests new avenues of investigation.

Older adults expend more listening effort than young adults recognizing speech in noise

PURPOSE

Listening in noisy situations is a challenging experience for many older adults. The authors hypothesized that older adults exert more listening effort compared with young adults. Listening effort involves the attention and cognitive resources required to understand speech. The purpose was (a) to quantify the amount of listening effort that young and older adults expend when they listen to speech in noise and (b) to examine the relationship between self-reported listening effort and objective measures.

METHOD

A dual-task paradigm was used to objectively evaluate the listening effort of 25 young and 25 older adults. The primary task involved a closed-set sentence-recognition test, and the secondary task involved a vibrotactile pattern recognition test. Participants performed each task separately and concurrently under 2 experimental conditions: (a) when the level of noise was the same and (b) when baseline word recognition performance did not differ between groups.

RESULTS

Older adults expended more listening effort than young adults under both experimental conditions. Subjective estimates of listening effort did not correlate with any of the objective dual-task measures.

CONCLUSIONS

Older adults require more processing resources to understand speech in noise. Dual-task measures and subjective ratings tap different aspects of listening effort.