Specific impairments of music-related functions not attributable to general perceptual, cognitive or motoric dysfunction, or low musical aptitude are referred to as "amusia" (Marin & Perry, 1999). This term was coined by Knoblauch (1890, cited in Johnson & Graziano, 2003), who was also the first to attempt a formal classification of music-related disorders. His work followed that of Gall (1825, cited in Wertheim, 1969), believed to be the first to hypothesise a specific brain substrate devoted to music processing. However, it was not until Broca's discovery in 1861 of an area in the left frontal lobe responsible for language articulation that neurologists started to seriously consider the possibility of music-specific brain areas (Dalla Bella & Peretz, 1999).
Numerous examples of double dissociation between music and language processing have since been reported. For example, a well-known Russian composer developed severe aphasia after a cerebrovascular accident yet continued composing notably brilliant musical works (Luria, Tsvetkova, & Futer, 1965; Peretz, 2001a). McFarland and Fortin (1982) describe the case of an amateur organist who, after suffering damage to the right cerebral hemisphere, was no longer able to play the organ yet verbal expression remained intact. Many similar cases (Basso & Capitani, 1985; Judd, Gardner, & Geschwind, 1983; see Marin & Perry, 1999 for a review) combined with converging evidence from a range of research techniques with non-brain damaged individuals (Avanzini, 2003; Ayotte, Peretz, & Hyde, 2002; Brien & Murray, 1984; Brust, 2001; Hyde & Peretz, 2003; Peretz et al., 2002; Sutherling, Hershman, & Miller, 1980; Tervaniemi & Huotilainen, 2003) has increased acceptance to the proposition that music and language functions are more or less independent at some level.