Ear Impressions

[frohike]

Ear impressions are a mold of the ear canal that is used to make custom earplugs.
These plugs are used to block or filter sound, and fit your ear so well, that you can swim without losing them. Check the ears of musician on stage and you'll see them.

Etymotic is a popular brand that provides earplugs with noise reduction from 9dB up to 25. Some of them even have circuitry that amplifies or reduces the volume to keep it on a safe range.

Searching youtube for "ear impressions" outputs a dozen videos of the procedure:

They put a blocking foam or cottom on your earplug attached to a thread, then they push the impression material inside the ear canal. If the "otoblock", as they call it, doesn't completely block the ear canal, the pressure of teh impression material can perforate the membrane and invade deep inside the ear, causing a devastating effect, and possibly a bonus chemical damange due to absorption of the material through the skin. But of course, the idea is for the block to block, so none of this happens.

This is a guideline for taking ear impressions (PDF) from the College Of Audiologists & Speech-Language Pathologists Of Ontario

This is a live seminar: Preventing Medical Errors for Audiologists - 2011 Update Look for the section "Ear Impressions". Some words of caution on it:

In our experience, the taking of ear impressions is by far the riskiest procedure that audiologists perform. With proper training and experience, ear impressions can be performed safely, and it is an integral part of our practice. We need to be diligent with ear impressions because it is an invasive procedure and can have unforeseen problems.

I collected this information because I'm thinking on getting an ear impression myself. So here it is, in case someone else is curious.