Occlusion effect is when you feel kind of opacity and resonance of your voice. It happens if your ear canal is blocked by some foreign body. In fact, what happens, is that the skull bone vibrations created by talking or eating, "collide" with the foreign body and this creates the strange echo.
Normally, these vibrations can "escape" through the outer ear canal and out into space and you don’t feel them. The thing is, that if a hearing aid blocks the open channel, the vibrations cannot escape, and they return to the eardrum. This phenomenon is significant mainly at low frequencies.
Generally speaking, the more the hearing aid is clogging the canal, the more this phenomenon is felt. And vice versa, the more the ear is ventilated, the less you’ll feel the effect.
So, things are better with CIC than they are with ITC or ITE since the later block a bigger portion of the canal.
BUT - if you compare CIC devices to Open-fit devices or to BTE devices with skeleton earmold, things are worse on the CIC option. That’s because open-fit and skeleton earmold keeps the ear ventilated.
We hope this answer helps. If you got any further questions, don't hesitate. Click here to get to our Questions & Answer page where you can ask your question. We would love to try and answer any hearing aids related question.
You could also find there some additional questions we already answered.