The common knowledge -general practice- is it does only partially before properly removed. Serious lesions can result from unskilled attempts of removing it, particularly when it is a compact mass. Swelling by water -i.e. during bath-shower and swimming will cause some hearing diminution but not deafness.

hypotetically long term blockage by wax might initially result in temporary loss of receptors in auditory neuroanl synapses with consequent impairment of hearing but hardly deafness. 

just a thought, Arne Brun

My understanding is that a loss of up to 20 dB HL can be attributed to a wax "plug" which is completely occluding the meatus. i.e any PTA returning 40 dB HL loss needs to be investigated otoscopically. Best practice however is to be doing otoscopy prior to PTA ;)

I imagine that a long term wax occlusion, could have similar impacts on the auditory neurons or auditory cortex as longterm otitis media - due to auditory deprivation. I have not seen any research or clinical evidence to back this up though.

"Swelling by water -i.e. during bath-shower and swimming will cause some hearing diminution but not deafness."

I don't think swelling in itself causes any hearing loss.   If however a small gap through is blocked then sudden deafness results.  I do not know how great, but Politzer says he never saw a case of complete deafness from wax.

"My understanding is that a loss of up to 20 dB HL can be attributed to a wax "plug" which is completely occluding the meatus"

Do you or anyone else have a source for this?

"Best practice however is to be doing otoscopy prior to PTA"

One of the consultants in the ENT clinic at a famous teaching hospital always sent his new patients for a PTA before seeing them and checking for wax.  I strongly disapproved of this, but have to admit he got away with it, rather supporting the theory that wax does not usually affect the hearing. 

"I imagine that a long term wax occlusion, could have similar impacts on the auditory neurons or auditory cortex as longterm otitis media - due to auditory deprivation. I have not seen any research or clinical evidence to back this up though."

There are reports of "impacted wax" correlating with degree of dementia.  I doubt if this is a direct causal link, but this may just be a risk marker for the well established link between PTA loss and later dementia.  There is also at least one intriguing report of impacted wax in chronic schizophrenia.

Cerumen or earwax is produced by cells in the external auditory canal. The function of earwax is to protect the outer, middle and possibly inner ear from external foreign objects and possible infection. However, when the earwax is impacted, deeply located and not removed, it may cause pain in the ear and tinnitus. If left untreated, earwax may lead to hearing loss. However, it is not certain if earwax could lead to nerve deafness. There may be association between accumulated earwax and use of hearing aids, especially among older people. 

The concluding wax can cause conductive hearing loss.

My clinical experience: Even if you have a free passage in the ear canal with a small visualisation of the tympanic membrane + a normal tympanometry you will most likely have a conductive effect on 6-8 kHz. Take it for granted! With an occluded wax plug you cannot rely on the PTA if there is any form air-bone gap found on the audiogram. Always tympanometry to find out if it´s occluded. Removal of wax is crucial for PTA.

If the question is referring to sensorineural components in long term conductive loss, there are some articles on the subject but haven´t read them more than the abstract so cannot discern on this matter. One example: 

Liberman, M. C., Liberman, L. D., & Maison, S. F. (2015). Chronic conductive hearing loss leads to cochlear degeneration: E0142341. PLoS One, 10(11) doi:10.1371/journal.pone.0142341 

An animal study about cochlear degeneration from chronic conductive hearing loss. Not exacty the same subject but could probably gain some knowledge about the neurophysiological consequenses of conductive hearing loss.

"you will most likely have a conductive effect on 6-8 kHz."

Are you saying there is a conductive hearing loss, worse at high tones, with an audimetric air-bone gap?  Such losses are generally unrecognised, even in audiology textbooks, and hence undiagnosed.   The cases known to me have all been due to elastic tissue in the ossicular chain, so I am not clear how wax could mimic this.

This is just a temporary loss due to wax and nothing more than a temporary conductive loss, of course. Nothing to do with the ossicular chain or any part of the middle ear. Nothing to be diagnosed. The air bone-gaps are not shown on the audiogram since you´re not measuring bone conduction at 6-8 kHz. Instead it shows itself as a "false asymmetry".

Speaking at an acoustic level you understand that the higher the frequency, the more likely the risk of diffraction or an attenuation of thresholds due to the wax. Just physical laws possible to calculate if necessary. Therefor you cannot trust what looks like an asymmetry on higher frequencies, because if you could measure bone conduction at those Hz you would get an air-bone gap due to wax. Even if it is not occluded.

On tympanometry you get no compliance or peak pressure and you get a small ear canal volume, if it is occluded. Then you do have a guaranteed conductive component at most of the frequencies. If the ear canal is not blocked but rich in cerumen you can´t rely on 6-8 kHz thresholds because it shows as a temporary conductive attenuation. Hope I make myself clear. You can have a perfect audiogram even though richly cerumen are present but the risk of getting a conductive component that is just some cerumen blocking the pure tones on it´s way to the tympanic membrane is possible, according to my experience.

Adobamen, P. R., & Ogisi, F. O. (2012). Hearing loss due to wax impaction. Nigerian Quarterly Journal of Hospital Medicine, 22(2), 117-120.

Subha, S. T., & Raman, R. (2006). Role of impacted cerumen in hearing loss. Ear, Nose and Throat Journal, 85(10), 650-653.

If it is impacted, yes it causes a conductive deafness.

The ear wax when disrupted through the use of items can expose the inner ear to direct attack by external influences and in severe cases could lead to conductive deafness

I think a large amount of ear wax can cause at worst temporary deafness. Once the wax build-up is removed, then normal hearing should resume.

"On tympanometry you get no compliance or peak pressure and you get a small ear canal volume, if it is occluded. Then you do have a guaranteed conductive component at most of the frequencies."

Agreed.

"If the ear canal is not blocked but rich in cerumen you can´t rely on 6-8 kHz thresholds because it shows as a temporary conductive attenuation. Hope I make myself clear. You can have a perfect audiogram even though richly cerumen are present but the risk of getting a conductive component that is just some cerumen blocking the pure tones on it´s way to the tympanic membrane is possible, according to my experience."

This is news to me (and to others!), and I am rather sceptical. If you have not already done so, this is worth writing up for an ENT journal.

" I think a large amount of ear wax can cause at worst temporary deafness."

So which is the one ref from a peer-reviewed journal that confirms this? (Large amount needs to be distinguished from total occlusion)

"If it is impacted, yes it causes a conductive deafness"

What is meant by impacted? Hard, compressed or airtight (totally blocking off the meatal route to air and sound)?

Frequent formation of wax indicates anesthesia of ext. aud. meatus. Some times they behave like cholesteatoma, granulation. Search neurological problem for a cure.@

This is independent evidence for the link between bile and ear wax:

"Zoonomia, Or, The Laws of Organic Life: In Three Parts

books.google.co.uk › books

Erasmus Darwin · 1803

In inflammatory or fenfitive fevers with debility , deafness may fometimes arife from a greater fecretion and abforption of the ear - wax , which is very fimilar to the bile , and is liable to fill the meatus auditorius , when it is too ...FOUND INSIDE – PAGE 128"

I think bile reaches the ear via the "new" connective tissue organ that connects many internal body parts. Other substances appearing rarely in the ear canal from distant body areas include urine, blood, viruses, cancer cells, etc.