A systematic narrative synthesis of acute amplification-induced improvements in cognitive ability in hearing-impaired adults

Are Current Data Sufficient to Infer that Hearing Aids Contribute to Postural Control and Balance in Older Adults? A Systematic Review

INTRODUCTION

Balance and postural control are related to hearing and hearing loss, but whether they can be improved with hearing aid use in older adults is not clear. We systematically reviewed controlled studies in which balance and hearing were tested in experienced older hearing aid users to determine the potential effects of hearing aid use on balance.

METHODS

The review was pre-registered in PROSPERO and performed in accordance with PRISMA. The question, inclusion, and exclusion criteria were defined using the Population, Intervention, Control, Outcomes and Study design (PICOS) framework. Older adults with hearing loss and no experience with hearing aids, or balance tests conducted without hearing aids in hearing aid users served as controls.

RESULTS

A total of 803 studies were screened, eight of which met the inclusion and exclusion criteria and were included in the final review. Five of the eight studies found a significant correlation between the use of hearing aids and the outcomes of the balance tests. The quality of the studies was limited or moderate. Key Discussion: The role of hearing aids in balance and postural control is unclear because of the quality of the papers and the sparse reporting of hearing status and hearing aids quality of fitting and use.

Relationship between cognitive domains and hearing ability in memory clinic patients: How did the relationship change after 6 months of introducing a hearing aid?

OBJECTIVE

We aimed to evaluate the relationship between hearing ability and cognitive domains and determine how the relationship changes after 6 months of introducing a hearing aid.

METHODS

We conducted a 6-month hearing aid lending study between September 2014 and March 2019, including 59 older participants who visited the Memory Clinic at the National Center for Geriatrics and Gerontology. The hearing level was assessed using pure tone audiometry. Speech intelligibility was measured using the monosyllabic word discrimination score. We assessed the relationship between hearing ability and cognitive domains using the Mini-Mental State Examination (MMSE) total score and four subscale scores (orientation, memory, attention, and language). Differences in the cognitive function between baseline (pre-) and 6 months later (post-) after introducing a hearing aid were also assessed.

RESULTS

The pre-orientation score was significantly associated with the pure-tone average (p = 0.013), and the pre-language score was significantly associated with speech intelligibility (p = 0.006) after adjusting for confounders. None of the MMSE subscale scores were significantly different between pre- and post-scores, however, an expectation of improvement with continuous hearing aid use was implied in the attention domain.

CONCLUSION

We found a significant association between hearing ability and cognitive domains in individuals whose cognitive functions were not considered healthy. The presence of a potential relationship between cognitive domains, hearing ability, and auditory compensation is suggested.

Speech Perception in Older Adults: An Interplay of Hearing, Cognition, and Learning?

Older adults with age-related hearing loss exhibit substantial individual differences in speech perception in adverse listening conditions. We propose that the ability to rapidly adapt to changes in the auditory environment (i.e., perceptual learning) is among the processes contributing to these individual differences, in addition to the cognitive and sensory processes that were explored in the past. Seventy older adults with age-related hearing loss participated in this study. We assessed the relative contribution of hearing acuity, cognitive factors (working memory, vocabulary, and selective attention), rapid perceptual learning of time-compressed speech, and hearing aid use to the perception of speech presented at a natural fast rate (fast speech), speech embedded in babble noise (speech in noise), and competing speech (dichotic listening). Speech perception was modeled as a function of the other variables. For fast speech, age [odds ratio (OR) = 0.79], hearing acuity (OR = 0.62), pre-learning (baseline) perception of time-compressed speech (OR = 1.47), and rapid perceptual learning (OR = 1.36) were all significant predictors. For speech in noise, only hearing and pre-learning perception of time-compressed speech were significant predictors (OR = 0.51 and OR = 1.53, respectively). Consistent with previous findings, the severity of hearing loss and auditory processing (as captured by pre-learning perception of time-compressed speech) was strong contributors to individual differences in fast speech and speech in noise perception. Furthermore, older adults with good rapid perceptual learning can use this capacity to partially offset the effects of age and hearing loss on the perception of speech presented at fast conversational rates. Our results highlight the potential contribution of dynamic processes to speech perception.

Plastic changes in speech perception in older adults with hearing impairment following hearing aid use: a systematic review

OBJECTIVE

Whether hearing aid use in older adults modifies speech perception over time is not clear. To address this question, we systematically reviewed studies in which older first-time hearing aid users and controls were followed over time.

DESIGN

The review was pre-registered in PROSPERO and performed in accordance with the statement on Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). The question, inclusion and exclusion criteria were defined using the Population, Intervention, Control, Outcomes and Study design (PICOS) framework. Studies with no controls, studies in which participants and controls were tested at only one-time point, with no follow-up and no pre-fitting measures, or when outcome measures did not include speech measures, were excluded.

STUDY SAMPLE

6113 studies were screened, out of which 12 studies, published between 1996 and 2021, met the inclusion and exclusion criteria and were included in the final review.

RESULTS

9 of the 12 studies found evidence for amplification-induced auditory plasticity in older adults, expressed in improved speech perception.

CONCLUSIONS

The results suggest amplification-induced improvements in speech perception over time, but findings should be interpreted with caution because overall improvements were small, and the studies' quality was moderate.

The Effect of Cognition on the Aided Benefit in Terms of Speech Understanding and Listening Effort Obtained With Digital Hearing Aids: A Systematic Review

Purpose Hearing aids are the primary rehabilitation devices used to compensate for presbycusis, though large intersubject variability in hearing aid benefit has been reported. This systematic review aimed to investigate how intersubject differences in cognition could influence the aided benefit for speech understanding and listening effort with bilateral digital hearing aids. Method Articles were selected through systematic searches in MEDLINE, Embase, Central, and reference lists. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed. Results The initial search resulted in 1,092 unique hits, of which 16 were included. The effect of cognition on the aided benefit in terms of speech understanding and listening effort was examined in 12 and four studies, respectively. The aided speech and listening effort benefit obtained from hearing aid use in general or from a specific digital feature (i.e., microphone directionality, noise reduction, amplitude compression, and frequency compression) was associated with four cognitive functions (i.e., working memory, processing speed, selective attention, and executive functions). Conclusions Hearing aid users with poorer cognitive functioning derived more aided benefit in terms of speech understanding from hearing aid settings facilitating the matching process between the incoming auditory signal and representations stored in long-term memory. However, since the number of included studies was limited, this trend should be interpreted with caution. Supplemental Material https://doi.org/10.23641/asha.13626509.