There are several disorders related to musical perception, such as congenital amusia (“lacking music”). Amusia refers to a variety of disorders that prevent recognizing or reproducing musical tones or rhythms. Its prevalence is around 4%. There are different types of clinical alterations related to amusia. For example, there are patients unable to whistle or sing (motor amusia), those who experience musical amnesia (unable to recognize familiar songs), those unable to read music (musical alexia), or write it (musical agraphia).
There is evidence in the literature pointing to a strong genetic basis for congenital amusia (see, for example, Perezt et al. The genetics of congenital amusia (tone deafness): a family-aggregation study. Am J Hum Genet 2007, 81(3):582-588). Amusia can manifest in different ways. This type of deafness can affect pitch perfection, meaning that a person with tone deafness cannot perceive the relative height of notes or differentiate between the notes of a melody. Instead of notes following a tonal pattern, this condition only allows those with amusia to perceive monotonous sounds that have no clear musical meaning. In other cases, a person with amusia has impaired rhythm perception; consequently, they also have difficulty dancing and performing tasks that require rhythmic skills.
Amusia is also classified as receptive (inability to understand music) or expressive (inability to produce music). The brain areas affected depend on the type of amusia. The right temporal lobe is associated with melody and pitch recognition, while the left is related to the analysis of pitch, rhythm, and tempo.
Amusia can also be acquired, and there are numerous cases described in the literature regarding neurological disorders.
