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The unsung story of amusia

image03We’ve all seen those contestants on shows like ‘X Factor’ or ‘Britain’s got Talent’ who are adamant they can sing, when the evidence unfortunately suggests differently. We ask ourselves how it is they can’t tell or we leap to the conclusion that it must be a set up. And, while I admit this may sometimes be the case, bear in mind there could also be a medical diagnosis to explain the situation. These individuals may have a condition known as amusia.

More colloquially called “tone deafness”, approximately 4% of the population suffer from amusia. This differs from the self-diagnosed 15–17% who believe they have the condition but are just poor singers – the difference being that poor singers are aware of their difficulty while true amusics are not. Amusics also tend to find music unpleasant to listen to, leading them to try to avoid situations in which they may be exposed – a rather difficult feat given the popularity and prevalence of music in modern society. Amusia can be congenital (i.e. the individual is born with the condition) or acquired (as the result of a brain injury or stroke). While amusia may seem less debilitating than other potentially socially isolating conditions such as dyslexia or dyspraxia, it can also cause an individual a great deal of stress, lead to social stigma and may affect an individual’s ability to process and learn tonal languages (e.g. Mandarin or Thai).

The term amusia was coined back in 1888 by a doctor called August Knoblauch, following the first diagnosis of the condition 10 years earlier. Nowadays, amusia is diagnosed by a set of six tests, collectively known as The Montreal Battery of Evaluation of Amusia (MBEA), which examine an individual’s musical ability for contour, scale, pitch interval, rhythm, meter and musical memory.

As yet, there is no consensus on the neurological causes for amusia but, a key feature apparent in those with the condition seems to be a deficit in fine-grained pitch discrimination (i.e. an individual’s ability to process a small change in pitch, such as a tone or semi-tone). Based on a number of studies which imaged the brains of amusics and non-amusics, two areas of the brain known to be involved in processing music appear to be affected in amusia – the auditory cortex (AC; especially the right AC) and the inferior frontal gyrus (IFG). These studies found a difference in cortical thickness of the AC and IFG, as well as a reduction in brain activity in the IFG of amusic subjects compared to matched controls. Amusics also showed reduced connectivity from the AC to the IFG (via a group of fibres called the arcuate fasciculus) which correlated with the degree of tone deafness of the individual, offering further evidence for the involvement of these areas in the condition.

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Whether someone with amusia can be “rehabilitated” or trained to improve their ability to process tone and to sing in tune is also up for debate. One small study in 2012 which provided five amusics with a 7-week course held by a professional singing teacher reported that four of the five subjects showed improved MBEA scores at the end of the study. However, whether the improvements were significant enough to warrant the time and resource invested into this study has been questioned.

It’s no secret that the term tone deafness is overused. But the condition, amusia, is a long-standing medical diagnosis which can have a significant effect on an individual’s social and educational life. Despite ongoing debate, the areas of the brain involved in music processing (the AC and IFG) differ both physically and in terms of activity in amusics compared with non-amusics. So next time X Factor hosts a “not so musically gifted individual”, I for one will hold my cynicism and consider a more medical reason before assuming it’s a set up.

Post by: Megan Barrett

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One Response to The unsung story of amusia

  1. Marie Mune says:

    I am tone deaf and aware of related deficits and have recently been exploring material on studies of amusia and the very interesting interesting work on the neurology. I am struck by the lack of the subjects views which I think may suggest a range of questions that seem to have been ignored. I think that subjects either invited to write their own accounts or interviews in qualitative studies may raise a number of relative questions.
    Marie

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