March 13, 2007 - Scientists at University College London and Imperial College London have shown how the brain makes sense of speech in a noisy environment, such as a pub or in a crowd. The research suggests that various regions of the brain work together to make sense of what it hears, but that when the speech is completely incomprehensible, the brain appears to give up trying.
The study was intended to simulate the everyday experience of people who rely on cochlear implants, a surgically-implanted electronic device that can help provide a sense of sound to a person who is profoundly deaf or who has severe hearing problems.
Using MRI scans of the brain, the researchers identified the importance of one particular region, the angular gyrus, in decoding distorted sentences. The findings are published in the Journal of Neuroscience.
In an ordinary setting, where background noise is minimal and a person’s speech is clear, it is mainly the left and right temporal lobes that are involved in interpreting speech. However, the researchers have found that when hearing is impaired by background noise, other regions of the brain are engaged, such as the angular gyrus, the area of the brain also responsible for verbal working memory – but only when the sentence is predictable.
“In a noisy environment, when we hear speech that appears to be predictable, it seems that more regions of the brain are engaged,” explains Dr Jonas Obleser, who did the research whilst based at the Institute of Cognitive Neuroscience (ICN), UCL. “We believe this is because the brain stores the sentence in short-term memory. Here it juggles the different interpretations of what it has heard until the result fits in with the context of the conversation.”
The researchers hope that by understanding how the brain interprets distorted speech, they will be able to improve the experience of people with cochlear implants, which can distort speech and have a high 
level of background noise.
“The idea behind the study was to simulate the experience of having a cochlear implant, where speech can sound like a very distorted, harsh whisper,” says Professor Sophie Scott, a Wellcome Trust Senior Research Fellow at the ICN. “Further down the line, we hope to study variation in the hearing of people with implants – why is it that some people do better at understanding speech than others. We hope that this will help inform speech and hearing therapy in the future.”
August 19, 2008 at 12:32 pm
DEAR SIR,
I AM PROFOUND DEAF HAD DISCUSSED TO THE DOCTOR FOR THE IMPLANT COCHLEAR EAR . THE DOCTOR DON’T AMDIT ME TO SURGERY IT IMPLANT. THAT IS WHY I NOT EXPERINCED IN BACKGROUND SCHOOL.MY MAINSTEAM SCHOOL HEARING WAS THERE. I WAS SPEND A SPEECH THERAPHY SO MANY YEARS THAT I WAS GROW UP TO RISE.BUT I DID NOT GOOD SPEECH IN EXPERINCE THAT THE DOCTOR SAID.THEY WERE NOT FAIR THEM SAID SORRY FOR ME.I ALMOST VERY SAD AND DISTRESS MYSELF PERSONAITIY .IN AUSTRALIA,I ALWAYS HAD CRYING AND PAINING WITHOUT IT ONE YEAR.THE DOCTOR BELIEVED TO ALLOW THE DEAF WHO EXPERINCE IN LIPREAD OR ORAL IN THE ORAL SCHOOL FOR FREE.I SURE I AM SUICIDE WHY IT USELESS FOR ME USE.
September 1, 2008 at 7:17 am
What?
September 1, 2008 at 7:18 am
I’m not sure I understand what is the test is all about.
September 22, 2008 at 10:49 am
This research give indications as to what parts of the brain is in function when the sound is garbled or difficult to comprehend (as it very often is after a cochlea implant). This gives scientist clues about 1, how the brain functions 2. how the brain functions after implanting a CI, how it tries to compensate for the lack of familiar sounds.
It could also help determine, via MRI scans, if any problems occur, wether the problem lie in the brain or in the implant itself.