How common is amusia?

The main project I work on at Goldsmiths is an investigation of congenital amusia.  So what is congenital amusia? Individuals with amusia don’t develop basic musical abilities, despite normal exposure to music during childhood, normal education levels and IQ, and no known neurological or hearing impairments. Amusia has been likened to other congenital (i.e. present from birth) disorders such as prosopagnosia (problems with processing faces), dyslexia (problems with language), and dyscalculia (problems with numbers), but the focus of difficulty in amusia is in processing music-like sounds (n.b. this can include aspects of speech too).

Amusics should be distinguished from those individuals who describe themselves as “tone deaf” on the basis of their singing – think X-Factor! Individuals with amusia are not just ‘bad singers’ – their primary problem occurs when they listen to music. They often can’t recognise familiar tunes or find musical sounds annoying/abrasive. This perceptual difficulty can affect their singing ability but only because they do not accurately perceive the sounds they are making.

I think congenital amusia is an absolutely fascinating condition – it gives researchers like me such a unique opportunity to work out how the brain processes music and to learn about the real world consequences of music processing being disrupted. At this point we have a large database of amusic (and matched control) participants who regularly take part in our studies, generously giving up their own time to help us out. They make my job very easy as they are all really nice people! I look forward to seeing each and every one of them.

I was interested to read an article out this month by Henry and Devin McAuley, who looked at the issue of how common amusia really is in the population. Since 2000 at least 20 papers (including my own) have written that amusia affects 4% of the population – based upon a paper by Kalmus and Fry (1980). No-one has ever really questioned this figure. But Henry and Devin McAuley suggest that the methods we use for diagnosing amusia are not ideal, because we use a single number as our cut-off point, based on statistical norms, to say whether someone is amusic or not. They suggest we should consider using multiple methods to diagnose amusia, including our current tests (e.g. MBEA) but also taking histories, structured interviews and questionnaires into account.

The authors are right to be cautious about test-based methods – this problem arises in a range of disorders, like dyslexia.  And fundamentally I like the idea of getting more information from each individual. In our research group we have done many questionnaire studies of our amusics’ everyday experiences with music and the results are always fascinating. Plus, talking to the individuals before and after testing sessions is where I get a lot of my inspiration for future work. So if the outcome from this paper is a re-emphasis on the individuals and their experiences, and not just their scores, then I will be happy.

Paper: ” On the Prevalence of Congenital Amusia” by  Molly J. Henry, J. Devin McAuley in Music Perception Jun 2010, Vol. 27, No. 5: 413–418.