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Causes of Hearing Loss (by Robert Donnan, York Hearing Practice)

By November 21, 2017March 22nd, 2018No Comments

Ear wax (or Cerumen) Is the most common cause of sudden mechanical hearing loss (‘conductive hearing loss’ being commonly a blockage in the outer or middle ear or a fault in the middle ear causing loss of sound transmission). Ear wax is an accumulation of secretions from secreting glands in the first third of the ear canal. A hearing loss will only occur if the wax blocks the whole diameter of the canal. It is more common in swimmers (as water swells the wax, and bacteria present encourage more secretions), those who use cotton buds (as they just push the wax further into the ear and damage the delicate hairs on the surface that move the ear wax out normally), and persons with hairy ear canals (as the wax accumulates and knots on the hair).  Treatment can include initially olive oil drops, safe irrigation usually by a nurse, and / or micro-suction usually by a suitably qualified dispenser or an ENT consultant / nurse). We can check your ears for excessive wax, show you a video screen picture of the problem and offer micro suction of ear wax.                  

Presbycusis (age related hearing loss, often associated with hereditary traits) The most common form of hearing loss that results in a slow, progressive deterioration of the hearing. Although there are varying pathologies that can result in presbyacusis, the most common cause is hair cell degeneration within the cochlea leading to fewer electrical impulse signals being sent to the brain. This degeneration is commonly caused by noise exposure, but can also be brought on by circulatory / blood quality changes (vascular), dietary (Diabetes for example), smoking and stress-related problems amongst many others. Presbycusis is permanent and is usually treated with the prescription of hearing aids.

However, most sufferers take several years to recognise presbycusis as it is a slow and progressive deterioration, using excuses such as ‘other people are mumbling’, ‘the TV adverts go up in volume’, ‘people don’t speak properly any more’, ‘if you would just speak clearly’, etc.  Speech components can be loosely described as being low middle and high frequency. The vowels being low frequency, deeper resonating elements that are powerful in their sound pressure, or energy.  The middle frequency parts are the flatter consonants, such as the m, n sounds, which are weaker in energy. The high frequency content would be the fricative consonants, like the quieter ‘t’ and ‘s’ that start and end words, and define clarity (the quietest being ‘th’, some 600 times weaker than the ‘ohh’ in ‘talk’. As presbyacusis has more impact on the higher frequencies, a sufferer may hear the volume of speech (the vowel content) but will inevitably miss the clarity (the fricative consonant content).

Thus  they will generally cope much better in one-to-one conversation where the brain can contextualise (fill in the gaps they are missing), than when in background noise  and the brain is bombarded with unwanted vowel sounds (unfortunately, background usually arrives at our ears as low frequency energy). Or in a situation where unconscious lip-reading is not possible. Digital hearing aids are mostly developed for this commonest form of hearing loss and wearers who address the problem soon enough will normally enjoy a very successful outcome. Those who wait over 7 years can expect a longer rehabilitation time.      

Noise induced hearing loss: Noise-induced hearing loss can be caused by long duration exposure to noise of seemingly acceptable levels that the person gets used to over a long time (such as factory machinery) or; by sudden high-intensity exposure (bangs, such as boiler-making, artillery or gun-fire), or by a combination of both. Explosive noise type exposure can often cause severe high frequency damage whilst very minimal low frequency damage (a ‘ski-slope’ loss). This means that a sufferer may hear low frequency volume of speech just as ably as a child, but may miss the high frequency clarity completely. As such, these persons can be in denial for longer periods and find it harder to accept the wearing of hearing aids, as they hear most sounds loud enough. RIC hearing aids usually overcome this type of loss, restoring clarity, whilst providing a comfortable, discreet often very successful solution.

Perforated Eardrums: May result from violent changes in pressure (diving trauma, a slap or explosion etc), direct trauma to the membrane (a cotton bud or hair clip) or excessive pressure build-up of fluid (infective or post-infective) within the middle ear. Patients suffering from perforated eardrums should seek medical attention prior to being fitted with hearing aids as some perforations can heal spontaneously, or may not have been operated on initially but maybe now can be. Permanent perforations can normally be easily treated with modern hearing aids, but wearers should give extra attention to cleaning and maintenance of the hearing aids so as to minimize the increased risk of infection. Some doctors may advise against the use of hearing aids altogether for this reason. Hearing aid results are variable in such a case.                                                                                  

Otosclerosis: A growth of extra spongy-type bone that forms on the middle ear bones that gradually hardens preventing transmission of the sound signal to pass from the stapes bone to the cochlea. It is a hereditary disease affecting 1 in 200 of the population, onset occurring usually between the ages of 20 and 30 years, commoner in women who have had children, often in one ear only. Patients with otosclerosis should seek medical assistance as surgery may be offered to solve the problem, normally in the form of a ‘stapedectomy’. Surgery is the treatment of choice but eventually the bony outgrowth may form back. There are contra-indications to surgery for some clients, and it should be noted that surgery is not always successful, which can in the worst cases lead to complete deafness. Hearing aids are usually successful in overcoming this type of hearing loss.                                 

Meniere’s Disorder (‘disease’, ‘syndrome’): ‘Meniere’s’ is the condition whereby there is abnormal pressure changes in the balance and hearing organs, due to over- and under- production of fluid within the inner ear. Symptoms include mild – severe attacks of dizziness and nausea, fluctuating, often worsening hearing loss (often one-sided, often reverse slope in shape) and possibly severe tinnitus. It can occur at any age but more frequently from 20 and 50 with the majority of sufferers being over 40. Around 10% of sufferers have a family history of the problem. A client suspected of having Meniere’s must be referred for medical attention prior to being fitted with hearing aids as amplification can induce attacks, and there may be more suitable alternative treatments. For those who have already received medical advice, and where any severe symptoms have diminished or disappeared, and who wish to receive treatment with hearing aids, those hearing aids with a volume control or remote control to counter any fluctuations in the hearing loss, and to open ear types to reduce the chance of any pressure change on the ear drum. Meniere’s sufferers will experience wildly variable results from hearing aids, although the majority can expect mostly successful outcomes, more so as the condition diminishes over time.                                                                                                                                              

Otitis Media: A build-up of fluid in the middle ear causing a conductive loss, usually as a result of blockage in the Eustachian tube (leading to the back of the throat). Patients with Otitis media should seek medical help urgently, and those that have been treated before, but with chronic recurrence should seek medical help on a regular basis as this condition can lead to other complications in the long term.  Chronic sufferers should only be treated with hearing aids when all other avenues have been exhausted and the ENT consultant has allowed this. Results from hearing aids in this case will often be poor.                                                                                                                                                                          

Bacterial infections / ototoxic drugs: Infections within the bloodstream can cause damage to the inner ear. These normally result in more rapid and severe losses and can also be congenital, being passed from mother to the unborn child. These hearing losses can often be treated with hearing aids, but with variable results.

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