Eline Borch Petersen

Hearing loss impacts neural alpha oscillations under adverse listening conditions

Degradations in external, acoustic stimulation have long been suspected to increase the load on working memory (WM). One neural signature of WM load is enhanced power of alpha oscillations (6–12 Hz). However, it is unknown to what extent common internal, auditory degradation, that is, hearing impairment, affects the neural mechanisms of WM when audibility has been ensured via amplification. Using an adapted auditory Sternberg paradigm, we varied the orthogonal factors memory load and background noise level, while the electroencephalogram was recorded. In each trial, participants were presented with 2, 4, or 6 spoken digits embedded in one of three different levels of background noise. After a stimulus-free delay interval, participants indicated whether a probe digit had appeared in the sequence of digits. Participants were healthy older adults (62–86 years), with normal to moderately impaired hearing. Importantly, the background noise levels were individually adjusted and participants were wearing hearing aids to equalize audibility across participants. Irrespective of hearing loss (HL), behavioral performance improved with lower memory load and also with lower levels of background noise. Interestingly, the alpha power in the stimulus-free delay interval was dependent on the interplay between task demands (memory load and noise level) and HL; while alpha power increased with HL during low and intermediate levels of memory load and background noise, it dropped for participants with the relatively most severe HL under the highest memory load and background noise level. These findings suggest that adaptive neural mechanisms for coping with adverse listening conditions break down for higher degrees of HL, even when adequate hearing aid amplification is in place.

Danish reading span data from 283 hearing-aid users, including a sub-group analysis of their relationship to speech-in-noise performance

Abstract Objective: This study provides descriptive statistics of the Danish reading span (RS) test for hearing-impaired adults. The combined effect of hearing loss, RS score, and age on speech-in-noise performance in different spatial settings was evaluated in a subset of participants. Design: Data from published and unpublished studies were re-analysed. Data regarding speech-in-noise performance with co-located or spatially separated sound sources were available for a subset of participants. Study sample: RS scores from 283 hearing-impaired participants were extracted from past studies, and 239 of these participants had completed a speech-in-noise test. Results: RS scores (mean = 41.91%, standard deviation = 11.29%) were related to age (p <0.01), but not pure-tone average (PTA) (p = 0.29). Speech-in-noise performance for co-located sound sources was related to PTA and RS score (both p < 0.01, adjusted R-squared = 0.226). Performance for spatially separated sounds was related to PTA (p < 0.01, adjusted R-squared = 0.10) but not RS score (p = 0.484). We found no differences between the standardized coefficients of the two regression models. Conclusions: The distribution of RS scores indicated a high test difficulty. We found that age should be controlled when RS scores are compared across populations. The experimental setup of the speech-in-noise test may influence the relationship between performance and RS score.

Cognitive Hearing Aids? - Insights and Possibilities

The working memory plays an important role in successfully overcoming adverse listening conditions andshould consequently be considered when designing and testing hearing aids. A number of studies ...