Hearing loss is one of the most common forms of sensory impairment, affecting individuals from all walks of life, but particularly those of advancing years. Recent studies have drawn a link between living in a muted world, a result of unmanaged hearing loss, to cognitive decline and the progression of dementia.
Research increasingly points to a correlation between diminished auditory stimulation and cognitive decline, even dementia. Researchers from the John Hopkins School of Medicine and other institutes conducted an experiment looking at 639 different adults aged between 36 and 90 years old. Over the period of 1990-1994 they underwent a series of tests to determine their cognitive and aural health and were monitored until the end of May of 2008. The researchers observed any potential development of Alzheimer's and dementia.
Of the participants, 125 had mild hearing loss (25 to 40 decibels), 53 had moderate hearing loss (41 to 70 decibels) and six had severe hearing loss (more than 70 decibels). During a median (midpoint) follow-up of 11.9 years, 58 individuals were diagnosed with dementia, including 37 who had Alzheimer's disease. The risk of dementia was increased among those with hearing loss of greater than 25 decibels, with further increases in risk observed among those with moderate or severe hearing loss as compared with mild hearing loss. For participants age 60 and older, more than one-third (36.4 percent) of the risk of dementia was associated with hearing loss. The risk of developing Alzheimer's disease specifically also increased with hearing loss, such that for every 10 decibels of hearing loss, the extra risk increased by 20 percent. There was no association between self-reported use of hearing aids and a reduction in dementia or Alzheimer's disease risk.
How does Hearing Diminish Late in Life?
The process involved in ‘hearing’ is a complex one, but on a primary level charts the capture and transfer of sound vibration, the conversion into electrical impulses and subsequent translation by the brain. Capture of sound vibration is achieved by means of tiny hair like receptors within the cochlea of the inner ear. As the body matures, these receptors die or decrease in quality. When a sufficient number of hair cells deteriorate the effective transfer of sound information is compromised and resultant hearing difficulties ensue. A cochlea loss is permanent in nature, largely due to the inability of the hair cells to regrow or regenerate. It is perhaps unsurprising then that many look towards some form of hearing assistance in order to mitigate the effect and indeed, maintain effective communication.
What are the Signs of Age Related Hearing Loss?
Losses attributed to age (presbycusis) and noise trauma (noise induced hearing loss) both damage the hair cells in the cochlea of the inner ear, although the rate of deterioration may be precipitated in the latter, depending on the length and intensity of exposure. Age-related hearing loss is largely gradational and may occur, albeit almost imperceptibly, for a number of years before someone recognizes any degree of hearing difficulty. The rate of decline varies between individuals but common signs, indicative of a resultant loss, include:
- Hearing loss which is often observed in both ears
- The perception that people are mumbling or speaking indistinctly
- The increasing need for people to repeat themselves.
- Marked difficulty understanding conversation in high levels of background noise.
- Awareness that the volume of the television /radio is too loud for others.
- Possible difficulty hearing the telephone ringing or the incoming voice.
How to Manage Hearing Loss?
For suspected hearing loss it is important to access a full diagnostic assessment, typically via referral from your doctor, through the local hospital audiology department, or, alternatively through a local hearing centre. The general recommendation, particularly for initial consultations, is that someone is accompanied, primarily to ensure the results are understood (and of course, heard) but also to help decide on the appropriate course of intervention. For most age-related losses, some form of targeted amplification can help to redress associative deficits in hearing but moreover, maintain access to communication in general:
Hearing Aids – Perhaps the most publicized hearing aids, whilst not able to restore ‘normal’ hearing, may provide sound amplification to mitigate a loss in a certain frequency range. The device sits inside, over or behind the ear and is designed to stimulate those remaining hair cells responsible for the transfer of sound via the auditory nerve to the brain.
Pros of Hearing Aids –There are different access routes offering a diversity of fitting prescriptions and range of types. Hearing aids have known (and measurable) benefits and can offer support in most acoustic environments. The scope of processing capability alongside the continued pursuance or miniaturised options means that the demands of most people can be met both acoustically and cosmetically.
Cons of Hearing Aids – Most devices are susceptible to water ingress and use in ‘extreme’ conditions may be contraindicated. For the majority of people, the option to wear the system at night is also not practicable. In spite of every move towards refining the cosmetic design, for those who are self-conscious about wearing a hearing system, Behind-the-Ear options, in particular, may still be seen as both cumbersome and too ‘apparent’.
Amplified Phones – As a long distance, communication medium, landline and mobile telephones are still the most popular choice. Standard designs however are often incompatible for those with a hearing impairment, on two counts – insufficient ringer volume and poor sound volume/ fidelity of the incoming voice. Amplified phones are designed to transcend these limitations by offering amplification levels of up to 60dB (against 8dB for normal phones), enhanced ringer volume control and oftentimes, a corresponding visual alert to signal incoming calls.
Pros of Amplified Phones - Devices often include visual enhancements such as large buttons and backlit keypads which may be used to address dual sensory needs, both visual and aural. Cordless or duo options (corded and cordless) increase accessibility and allow for flexibility in terms of moving between locations. Many designs are often very simple to use, with a ‘plug-n-play’ set-up configuration.
Cons of Amplified Phones – Certain models require their own power source to the mains and will not work in a power cut. The level of choice may make the selection process seem overly complex and discourage many from exploring options within this product range. These devices, whether corded, cordless or mobile, are only available from the private sector.
Alerting Devices – Often standalone products designed to ‘alert’ or capture the user’s attention. They may be used in forewarning against potential hazards, such as amplified smoke detectors, or to draw one’s attention to internal communication alerts, such as the telephone or doorbell ringing.
Pros of Alerting Devices – Certain models are portable and can be moved around the home as well as taken on the road. Devices often include a second sensory trigger in the form of a vibration function, whether on the device or as an added vibration pad.
Cons of Alerting Devices – May also wake or draw attention to other household members or, in extreme cases, one’s next-door neighbor. Certain devices are battery powered and therefore will not function when the battery is depleted.
The above is a sample of the various technological frameworks which may help to minimize the isolating effects of hearing impairment. The use of hearing aid amplification, alongside Assistive Listening Devices, cannot ‘cure’ hearing loss but can certainly help to safeguard against (or at least inhibit) the associated isolation, frustration and cognitive decline often seen in ‘unmanaged’ cases.