Congenital cerebral anomalies, Isabel Peretz believes, lie behind the phenomenon of amusia - the inability of some persons to recognize or produce musical sounds. The Université de Montréal neuropsychologist has just published her findings in two articles appearing in the January 2002 editions of two major journals, Neuron and Brain. The first article presents the case of Monica, a woman in her forties, for whom music is nothing but "stressful noise." The second article details the results of a study of 11 subjects who share this total absence of musical sense.

According to Ms. Peretz's research, amusia is not the result of poor education or environment but from a malformation that's already present at birth. "Music comes naturally to most human beings," she explains. "But for certain individuals, rhythms, melodies and chords make no sense whatsoever. What's fascinating about the people we encountered is that language is not affected. This means there's a region in the brain that's dedicated to musical perception." People who suffer from amusia can actually lead perfectly normal lives. Monica, for instance, has a master's degree. Her IQ is 111 and she has an excellent memory. Her amusia is not due to hearing loss, lack of exposure to music or cognitive deficits. Yet to her, Beethoven's Ode to Joy, the opening notes of La Marseillaise or the refrain of Frère Jacques all sound the same. On the other hand, she is perfectly able to recognize the human voice, and has no trouble telling a car horn from the sound of a barking dog.

Monica's anomaly, which thousands of other people also share, is probably located in the auditory cortex of the brain. But Ms. Peretz's research doesn't stop there. She has effectively laid to rest the mystery of amusia's origins. Its first description as a pathology dates back to an 1878 account of a 30-year-old man who was described as being totally incompetent in music, despite being fluent in three languages as well as his mother tongue. Despite the existence of such cases, it was widely thought that the causes of amusia were non-biological. Monica proved to be the most spectacular of a group of 11 people suffering from amusia that the research team recruited using small ads in different media. Ms. Peretz and doctoral students Julia Ayotte and Krista Hyde, her co-researchers, examined some 50 people in all. Of these, fewer than a dozen were retained for testing. The article published in the January 31 edition of Brain reports that systematic evaluation of the amusia sufferers, who considered themselves severely handicapped in the area of music, despite their efforts to learn music, "confirms the presence of a deficient system in the comprehension of music." Musical incompetence appears as an accidental disturbance in their nervous system which, whatever else, presents no significant cognitive or affective dysfunction.

Where the discovery may prove most remarkable is in genetics. "If we can isolate the gene that characterizes persons who suffer from amusia, we'll be able to more or less recognize the gene for music," says Isabel Peretz. "It may not happen in my lifetime, but I think we're heading in that direction."

Researcher: Isabelle Peretz
Phone: (514) 343-5840
Funding: Canadian Institutes of Health Research (CIHR)