Hard to swallow: April 2006

For the majority of people music is a simple pleasure that is taken for granted, but the ability to distinguish between rhythm, melody and tone - and thus different pieces of music - is not a gift that is at everyone's disposal.

"Amusia" was first recognised in Grant-Allen's 1878 study, in which a 30-year-old man with a normal education and without neurological lesion was unable determine the difference in pitch of two tones, recognise familiar melodies or "carry a tune". According to the neurology journal Brain, "congential amusia is related to severe deficiencies in processing pitch variations [and] extends to impairments in music memory and recognition, as well as in singing and the ability to tap in time to music".

Its investigation, "Congenital amusia: A group study of adults afflicted with a music-specific disorder", also points out that while language and music have many similarities, with both linguistic and musical understanding developing in children "without conscious effort or formal instruction", amusia affects only the "musical domain". Indeed, in a 1984 study Geshwind unearthed a man who "could not sing, nor discriminate between two pitches and could not keep time", yet was fluent in three foreign languages.

It is this "selectivity", as termed by Brain, that makes the condition so peculiar. Its study showed amusical subjects "to interpret intonation in speech properly, to identify well-known figures from their voice and to identify and recognise common environmental sounds, such as animal cries and ringing sounds". Furthermore, all but one of the subjects identified and recognised familiar songs when hearing the opening lyrics. However, the cause of amusia, while thought to result from "a slight disruption in the wiring of the auditory cortex", remains unconfirmed.