A study published in the Journal of the Association for Research in Otolaryngology (JARO) reports that people with normal hearing can train their brains to better understand speech in low signal-to-noise environments.
From The Brighter Side:
For the training, participants in the 40-person experimental group compared multiple series of rapid tones (think beeps or clicks) in nine sessions over three weeks. Compared to members of the 37-person control group, who were asked to detect a single tone in , those in the experimental group showed overall improvement.
The rate discrimination study is the first to show that "auditory training promotes neural changes in the brain, known as neuroplasticity," Gordon-Salant said. "The results offer great hope in developing clinically feasible auditory training programs that can improve older listeners' ability to communicate in difficult situations."
When I'm in a noisy restaurant, I often think of author Douglas Coupland's account of sneezing up a piece of living tissue and how he became hypersensitive to noise after that:
I quit smoking on Halloween 1988. In December 1988 I was walking to work in a snowstorm when I had the biggest sneeze of my life and afterwards found in my hand a clump of living tissue the size, shape, and colour of a Thompson seedless green grape. It had veins. Of course this freaked me out, and I went right to a doctor, who said that I should actually be thankful, because "At least it's not inside you any more." He made sense. But from that morning on, my hearing became hyperacute and hasn't wavered since. It's not just noises (of any sort) that shut me down (and by "shut me down," I mean they stop my body in mid-motion). Leaf blowers and hammers are the worst. But after the morning of the nasal incident, I also lost my ability to focus sounds. Restaurants are the worst. Or people in Europe who use cellphones on trains — people who use their outdoor voices indoors. I carry cards in my wallet to this effect. They read, I AM UNABLE TO "FOCUS" SOUND AND AM UNABLE TO HEAR YOU PROPERLY. PLEASE HAVE PATIENCE. I hand them out mostly to airline employees and hotel front desk staff. At first, they tend to think I'm running a charity scam, and then they realize I'm for real. I no longer attend large events that take place in big rooms. Also, in the 7,000 or so nights since then, I've not once been able to sleep without earplugs, and at its very worst, in 1993, I couldn't stay in hotels or do any work of any sort until late at night and into the early morning, when most people are asleep. So when I found out that Marshall's hearing went cuckoo after they took a lump out of his head, I said, "Yes, this is someone I want to write a biography about."