Sir Sean Connery
A 62-year-old woman is providing new insights into how the human brain works after becoming the first person to be diagnosed with a condition that leaves her unable to recognise voices. The successful British businesswoman, who is normal in every other way, is the first known case of someone being born with developmental phonagnosia, which leaves her unable to recognise even the voices of her own family. Her condition is so profound that she often avoids using the telephone and struggles to identify people speaking on the radio. Neuroscientists have now performed a series of tests and brain scans while asking her to listen to a range of recorded voices.
They found that while she was perfectly able to understand what was being said, she was unable to identify a speaker as someone she had been listening to a few minutes earlier. Researchers are finding that her condition goes beyond a simple inability to remember voices, as she even has difficulty discriminating between two voices played back to back. Brain scans taken as she listened to voices showed her brain reacted differently from most people’s, suggesting it is unable to process information from voices about speaker identity.
Professor Belin has been working with Dr Brad Duchaine, from University College London’s Institute of Cognitive Neuroscience, who was the first to recognise that the woman, identified only as KH, suffered from phonagnosia. She came forward after reading about work that Dr Duchaine had been doing on prosopagnosia, a condition where people are unable to recognise and remember faces. The woman, who is a management consultant, agreed to take part in a series of tests and has now undergone brain scans in Glasgow.
She revealed that she has struggled with recognising voices all her life and even has difficulty recognising her daughter. She avoids using the telephone and only answers calls that have been booked in advance so she knows who she is talking to. In one embarrassing incident, KH was speaking with a group of colleagues at a meeting when someone came up behind her and began speaking. As she did not recognise the voice, she did not turn around to acknowledge the person. She later realised, however, that the person was an important colleague and feared that her failure to acknowledge their presence could be interpreted as a snub.
In one test, KH was unable to identify the voices of a series of well known and distinctive celebrities, including Joanna Lumley, David Beckham and Margaret Thatcher. She did however manage to identity the Scottish accent of Sir Sean Connery. Another test showed how she could not distinguish between two individual speakers when their voices were played one after the other.
Scans revealed that a part of her brain known as the temporal voice area was far less active on the right hemisphere of her brain while she had normal activity in the left. The finding suggests that in the human brain, the right side is more important in voice recognition while the left is used to understand words.