Why Exactly Does the Ringing Get Louder When You Plug Your Ears?

We all know that tinnitus gets louder when we plug our ears. This is so obvious and common that there's little need to debate it.

But *why* does this happen?

One common theory is that by blocking off all outside sounds, you reduce further the ability for natural sound waves to get to the cochlea/brain, and thereby increase the impovershed sound state further. But does this really make sense? If you put your finger in your ear, in out in out in out, your tinnitus immediately goes up down up down up down. Could the brain really react to this "impovershment" so quickly? Seems unlikely to me that the up-/down-filtering of the gain of the auditory system would happen on such a timescale (our hearing would be bouncing around like a pinata at all times if that were the case).

Another common theory - probably the most common one - is that by blocking out the rest of the world, we lose all natural masking, and so hear the tinnitus more clearly. But let's think about this one too: when I'm in the car, and I put in my musician plugs and block out 15 decibels or so, what that means is that the 80 dB engine of my car is now reduced down to a nice, comfortable 65 decibels. This is still louder than a moderate office environment, and about the same volume as a normal conversation from 3 feet. And yet, because my plugs are in, my tinnitus can blare above the constant 65 dB car engine that should normally do a pretty darn good job of masking. So what gives here?

Anyone else have any thoughts/insights?

-Matt

 

I would go with your 2nd theory why the T increases.

 

outside noises and cause something call residual inhibition and when you plug your ears the phantom ringing is all you hear.

 

Okay...but in the car I can still hear the engine noise all around me. It's everywhere. It's just dampened to 65dB. So it's not really fair to call that a sensory deprivation situation, is it?

 

Yeah not sure.

 

Another theory: tinnitus isn't a "phantom sound" at all. Rather, there actually is a sound being emitted by neurons extremely close to, or in, our cochlea. When we block our ears, the sound increases because it has no place to escape (ie. it leads to an occlusion effect).

This effect would occur, regardless of whether you were in a quiet or a loud environment - in either case, occlusion should occur. And it would have nothing to do (directly) with masking, or residual inhibition, or any of that stuff.

 

If this were true (and I'm not saying it is, but let's go with it for the moment, see where it takes us), then the problem may not be that our ears/brains are creating a phantom sound, but rather that they are not properly inhibiting the natural neuronal sounds that occur. Because these neurons are always firing in everyone's ear...it's just that most people have mechanisms to filter out that sound so it doesn't reach conscious awareness. Maybe for us, that filtering mechanism has broken? (This would fit perfectly for pulsatile tinnitus, but maybe it fits for all tinnitus)?