It continually astounds my family that I can pick up a muttered word in another part of the house on an average quiet evening but that I cannot hear someone four feet away shouting, "Marnie! Marnie!" while the tap is running. That I can hear my mule braying from a mile away but that a person speaking to me in a moderately noisy auditorium might as well be a Martian speaking utter gobbledegook. That I can understand you perfectly when we speak face-to-face but that if you approach and speak to me while I'm already in a conversation my brain may completely paint you out of the picture. Why I ignore you when I've been listening to the TV, or the radio, or another person. Why I act as if you don't exist.
I think my brain has learned to shut out sounds that it can't cope with, reducing the confusion of monaural hearing by listening to as little as it can at any one time. Here's an example: when I'm walking with my family and hear a truck passing on the highway a mile away, I suddenly become deaf to words. I only hear the vehicle, and I can't tune back in to what's around me until I identify its location. My brain screams, "truck!" and my thoughts scatter like sheep.
I was looking for online information about clinical research today—hoping, actually, to sneak into some sort of tinnitus study—and I found an article that was, in its own way, cheering. It was published by the National Institute for Rehabilitation Technology, and this is the relevant paragraph:
"The human brain processes the signals from the two ears in a very special, coordinated way. One of the most important of these brain processes is that which cancels background noises so that the person can better discriminate and understand a person's voice that is mixed in with all the background noise (as in a factory, motorboat, party with loud music, etc.). Another of these brain processes enables a person with two good ears, to hear three or four people speaking at the same time - in a place without background noise - and be able to listen to just the one voice that is of interest. EXCEPTIONS to these benefits occur when a person has lost most or all of the hearing in one ear. (1) Unaided, this person understands very little of human speech under either of the conditions just described." (Emphasis mine).
It's true. It's bizarre. It belies the high functioning of my useful ear, which does a pretty good job most of the time, and it's hard to explain. "Why," my loved ones must ask themselves, "can she not hear me? Why, when she's not really that deaf?"
Some good news—a friend of mine who used to be an audiologist tells me that CROS (contralateral routing of signal) systems do help people like me. After talking with her and doing a little research, I really want to try it. Without health insurance I don't think I'll be trying it soon, but it is exciting to think that there might be a way to give my brain a little of the audible stimuli it's been lacking—a way to hear more than one thing at a time again, and maybe get a better picture where that truck is coming from.