Hearing loss in the adult
Posted on 30 November 2020
For adults, hearing loss can also be divided in conductive and sensori-neural (nerve) groups. Some conditions, characteristically associated with hearing loss in childhood, can also present in adulthood – serous otitis media (fluid in the middle ear) for one. According to Dr Ludwig de Jager, ENT at Mediclinic Potchefstroom, “The irony is that congenital hearing loss (hearing loss present at birth) first might manifest in early adulthood.”
The two most prevalent types of hearing loss in adults fall in the sensori-neural cadre: noise induced hearing loss and hearing loss of age – presbycusis.
Noise induced hearing loss mainly has an industrial and recreational base. Shooting is probably the prime recreational activity associated with noise induced hearing loss. Defiance in terms of using hearing protection in general unfortunately renders many individuals unnecessarily vulnerable. The potential detrimental effects of personal listening devices also should not be underestimated.
Dr de Jager explains that “Noise induced hearing loss intuitively implicates prolonged exposure to harmful levels of noise (as in a factory) but exposure to a single loud sound (e.g. shout, rifle fired close to the ear, fire cracker, horn or siren going off in close proximity) might cause ‘acoustic trauma’ which could result in temporary but often permanent hearing loss.”
“Noise induced hearing loss characteristically targets the higher frequencies: 3 – 6 kHz resulting in the typically notched audiogram. It is possible that only one side could be involved – with asymmetrical hearing loss resulting. The situation can be further complicated when the effects of hearing loss of age are superimposed,” he continues.
According to Dr de Jager, hearing loss of age (presbycusis) can in a sense be considered a congenital issue: we are (genetically) programmed to age. But there is another side to it: this type of hearing loss also has a ‘wear and tear’ component with the latter the result of the sum of the sound (or noise) that we have been exposed to during our lifetimes. To boot, other health issues could also damage the inner ear and contribute to hearing loss – hypertension, vascular disease, and diabetes only to name a few.
Dr de Jager explains that the hearing loss (in presbycusis) initially is subtle and ironically often noticed more by others than the patient. Patients typically have difficulty hearing when there is competing background noise, or more than one person involved in conversation. Many a time they fare better with male voices. A common finding is the paradoxical hypersensitivity to loud sounds. This results from disordered processing of sound in the inner ear.
The hallmark of presbycusis is progressive, symmetric high frequency hearing loss over many years. It is interesting to note that it affects more than 50% of adults by age 75, most adults over 80 and nearly all adults older than 90. It is also more common in men.
Both noise induced hearing loss and presbycusis may have another annoying accompanying symptom: tinnitus. Tinnitus is commonly perceived as a steady ringing, rushing or static sound (in the ears or head). It is the result of damage inflicted to the neural elements in the inner ear (organ of Corti).
Management of hearing loss in the adult is no different compared to that in the child: medicine or surgery might be able to restore hearing in the conductive group. A hearing aid could also be considered where surgery for whatever reason is not possible. Compensating for the loss is relevant in the sensorineural contingent. Patients with moderate to severe loss should benefit from hearing aids but those with profound loss will theoretically do better with cochlear implantation. Bone anchored hearing aids could be considered in patients with conductive loss where surgery for whatever reason is not considered.
Dr de Jager admits that there is unfortunately a group of patients who experience significant difficulty with speech discrimination despite appropriate amplification. This is a huge dilemma and patients compensate with lip reading and avoid having conversations where there is background noise. There also are other assistive listening devices which could come in handy to make life easier for the hard of hearing: TV amplifiers, telephone devices, doorbell sensors and smoke alarms only to name a few. As assisting in diagnosis our audiology colleagues play a significant role in the management of patients with hearing disabilities.
What are the risks of untreated hearing loss in the adult?
Dr de Jager believes that the potential effects of hearing loss in the adult, and particularly the older adult, should not be underestimated. It significantly impacts everyday life causing loneliness, isolation, dependence, huge frustration and even anger. Hearing loss may add to the perception that an older person is ’slow’ or worse still; losing his or her faculties, which is usually not the case. This negative perception from others can result in negative self-perception, which in turn leads to lower self-esteem, frustration and even depression.
But it is potential cognitive decline in the hard of hearing that has become a talking point and particularly the association of hearing loss with dementia. Hearing loss and dementia have become accidental partners in that they share common risk factors: old age, vascular conditions (caused by diabetes and smoking) and social factors. But the plot thickens: in selecting for loneliness and feelings of social isolation, the risk of those with hearing loss developing dementia potentially increases. And hearing loss may place an additional load on the mental resources of the already vulnerable brain in that the person who has difficulty hearing now needs to work harder to decode and process sounds, resulting in fewer resources for memory and other cognitive functions.
There is also evidence of a potential ‘second hit’ with a physical manifestation: decreased input from auditory signals may result in accelerated rates of whole brain atrophy as well as specific volume declines in areas of the brain which are important not only for spoken language processing, but also for semantic memory and sensory integration and are involved in early stages of cognitive impairment or early Alzheimer disease. Hearing loss thus might be more than just an accidental partner when it comes to dementia but could in itself be a potential cause of dementia. According to Dr de Jager, research is ongoing in this field.
And how is this managed? Lifestyle changes that may reduce the risk of developing dementia – healthy eating, regular exercise, challenging the mind, keeping socially active and of course: manage hearing loss.
Hearing connects us to people enabling us to communicate in a way that none of our other senses can achieve. And language defines us as human beings. Its loss takes that away from us. This is reason enough to do what we can to preserve our own hearing but also to have empathy with those suffering hearing loss and deafness and to do all we can to prevent them falling into the abyss of loneliness and frustration and humiliation.
Further reading: Hearing loss in children