Auditory Aging: A Look at Hearing Loss in Older Adults Based on an article by Kathleen M. Cienkowski, Ph.D.
- The natural aging process affects not only the ability to detect sounds at soft levels (hearing thresholds), but also the ability to understand speech at typical conversational volumes.
- No single factor is the cause of presbycusis, or age-related hearing loss. Changes are seen throughout the hearing system. Many people who have presbycusis report that they hear speech, but have difficulty understanding, particularly in the presence of background noise.
- Because presbycusis results in permanent sensorineural hearing loss, hearing instruments are the treatment of choice.
- Many older adults do not report any hearing difficulties in quiet situations or for one-on-one communication. Even if a hearing loss is present, they will seem to be able to get by. However, in environments with lots of noise or echo (reverberation), older adults identify fewer words correctly than younger adults with equivalent hearing.
- When listening to speech, sounds are available for only a few fleeting moments before they disappear, and within that timeframe, the listener is expected to understand what has been said. Age affects one's ability to process rapidly changing auditory information.
- The central auditory system coordinates information between the ear and brain. It plays an important role in processing complex information such as understanding speech in the presence of background noise or detecting differences in signal loudness or duration. Deterioration of neurons in the central auditory pathways (the pathways that transmit information from the cochlea to the auditory cortex in the brain) may limit an individual's ability to separate out important components of complex signals.
- It has also been suggested that changes in global cognitive ability may underlie some aspect of the speech perception difficulties. These are changes in cognitive skills such as memory and attention, independent of hearing ability. Investigators have suggested that reductions in working memory and other facets of cognitive function may impact word recognition ability.
- There is some evidence to suggest that memory performance declines for older adults with hearing loss because of increased demands on attention. It is possible that hearing loss places more demands on auditory attention when distracting signals are present.
- In studies of working memory and brain imaging, researchers found older adults activated more brain regions than young adults for the same task. This has led some researchers to speculate that older brains activate new areas in order to compensate for declines in other areas. This highlights the potential for brain plasticity (the ability of the brain to learn and change) across the life span.
