Our ears are constantly working, constantly receiving. Perceiving and identifying sounds is a highly complex operation. An array of anatomical structures and processes are responsible for ensuring that signals are picked up from our environment, then processed correctly in the brain. But what exactly is hearing loss and how does it manifest itself?
Hearing loss is a partial or total inability to hear. The spectrum of hearing loss ranges from mild to profound and the causes are many and various. One common feature is that people affected by hearing loss are frequently unaware that there is a problem at first as the symptoms rarely set in suddenly. Hearing difficulties typically develop gradually, over a long period of time. People get used to incipient hearing loss and do not initially feel significantly disadvantaged as the brain can offset the hearing deficits for quite a while. Usually, it is people who are in close contact with the affected person who confront him or her with unpleasant questions. For instance, they might ask why the TV is turned up so high. Or friends might get frustrated when the person concerned is once again unable to accurately follow the storyline in some form of entertainment.
One of the main causes of hearing loss is noise. We are permanently surrounded by sounds: whether the roar of traffic, the clatter of building sites or the din of loud music, our ears have to deal with a veritable barrage of input. But high-volume noise is not the only cause – disease, accidents, stress, hereditary health conditions, or quite simply the natural ageing process can lead to hearing loss as well.
So there may come a time when we have to face the fact that our hearing is no longer working the way it should. A variety of measures can be taken, depending on the precise causes of the hearing loss.
One of the commonest causes of hearing loss is a build-up of compacted earwax. Attempting to remove earwax from the external auditory canal using Q-Tips often has the opposite effect: too much wax is removed, the sensitive skin – or even the eardrum – is damaged and earwax is pushed deeper into the auditory canal. As a result, the self-cleaning mechanism is impaired and the earwax forms a plug which can ultimately block the auditory canal. However, retained fluid or foreign bodies can also lead to acute hearing loss.
Inflammations, build-up of fluid behind the eardrum, perforation of the eardrum, and otosclerosis (hardening of the tiny bones in the middle ear known as ossicles) are among the most common problems affecting the inner ear. Babies and children are particularly susceptible to acute middle-ear infections – and an infection will often make a person vulnerable to follow-on infections.
It is in the inner ear that the actual process of hearing takes places. The hearing organ, the cochlea, is the control center where incoming sound waves are processed and converted into nerve impulses. As we now know, the auditory system is extremely sensitive to loudness, whether this be sustained exposure to noise or a one-off blast of sound. Repeated, intensive exposure or long-term exposure to sound impairs the function of the cochlea. In order to protect themselves from excessive volume, the sensitive hair cells inside the inner ear “mute” themselves, as it were – they reduce their activity. They can regenerate for a while, assuming there is enough time for recovery. However, if the ears continue to be exposed to sustained loud sounds and noise, chronic hearing loss may ensue.
Besides age-related wear and tear, tinnitus, sudden deafness, inflammation of the inner ear or a tumor may also be causes of hearing loss. Hearing loss in the inner ear cannot be treated medically but can be alleviated with hearing aids.