A new study has shed light on the impact of aging and asymmetrical hearing loss on speech discrimination (SpD). Published this week in Communications Medicine, the research examined data from over 2,700 participants aged 10 to 99 years.
This comprehensive retrospective study aimed to explore the relationship between age, pure-tone audiometry (PTA) outcomes, and SpD, with a particular focus on how differences in hearing thresholds between the left and right ears influence speech understanding.
The Relationship Between Aging and Speech Discrimination
The study revealed a noticeable decline in SpD as age increased, particularly among the oldest participants. The analysis showed that SpD scores were significantly lower in older age groups (70-99 years) compared to younger ones (10-39 years), highlighting a clear deterioration in speech discrimination abilities with aging.
This decline was consistent across mild, moderate, and severe hearing loss categories, highlighting that aging itself plays a critical role in reducing speech understanding.
One of the key findings was that even when controlling for hearing loss severity, older individuals consistently showed poorer speech discrimination abilities. This suggests that aging itself, independent of the degree of hearing loss, plays a crucial role in diminishing speech understanding. This decline in SpD with age underscores the importance of early detection and proactive management of hearing loss, especially as the global population continues to age.
Impact of Asymmetrical Hearing Loss
In addition to the effects of aging, the study also explored how differences in hearing thresholds between the left and right ears (asymmetrical hearing loss) impacted SpD. The researchers found that in cases of moderate to severe hearing loss, significant differences in SpD were observed between the better-hearing ear and the worse-hearing ear when the threshold difference was 20 dB or more. This was particularly evident in the nondominant ear, where speech discrimination abilities were significantly worse.
The study’s findings suggest that asymmetrical hearing loss, where one ear is significantly worse than the other, can lead to a marked decline in the ability to understand speech. For example, nondominant ears with a threshold difference of 20 dB or more consistently showed lower SpD scores regardless of the individual’s age group.
The researchers emphasized the importance of fitting hearing aids in both ears, even if one ear is significantly better than the other, to maintain speech discrimination abilities and improve overall communication.
Clinical Implications and Future Research
The implications of this study are significant for clinical practice. The findings suggest that traditional hearing screening methods, which often focus solely on pure-tone audiometry, may not be sufficient to fully assess an individual’s hearing capabilities, particularly in older adults.
The researchers advocate for including speech discrimination tests in standard hearing assessments, especially for older patients, to ensure that their ability to understand speech is accurately evaluated.
Moreover, the study raises important questions about the management of asymmetrical hearing loss. Given the clear impact on speech discrimination, there is a need for innovative approaches to hearing aid fitting that take into account the differences between the ears. This could involve more personalized hearing aid settings or the development of new technologies aimed at improving speech discrimination in the worse-hearing ear.
Future research is expected to further explore the relationship between asymmetrical hearing loss and SpD, particularly through longitudinal studies that follow individuals over time. Such research could provide deeper insights into how early intervention with hearing aids or other audiological treatments might preserve speech discrimination abilities and enhance the quality of life for those with hearing loss.
Reference:
Wasano, K., Nakagawa, T., Kaga, K. et al. The effect of aging and asymmetrical hearing on speech discrimination. Commun Med 4, 166 (2024). https://doi.org/10.1038/s43856-024-00587-8
Source: Nature
