Music-specific disorders
Music-specific disorders impede one's ability to comprehend, respond to, and enjoy music; these disorders can be both congenital and acquired. They may interfere with one's ability to perceive elements of music, such as pitch, melody, harmony, and rhythm; the ability to react both emotionally and with bodily movements to music; to form music-related memories; and the ability to create and perform music. While music is traditionally regarded as a purely auditory phenomenon, modern scientific study of music – the musicology – is a interdiscipline between psychology, neuroscience, and cognitive science. Investigating music-specific disorders under these scopes has helped us better understand the psychology and neuroscience of music.
Background
Modern musicology identifies music with a few common, though not mandatory, characteristics: pitch, melody, harmony, timbre, time relations,, and its ability to evoke an emotional response.Pitch
In the physical sense of the term, the word "pitch" refers to the frequency of a sound. Another term that is frequently used by music neuroscientists is "fine-grained pitch processing" which refers to the ability of a person to distinguish minor changes or fluctuations in pitch. Processing pitch is an extremely integral part of music cognition. Recent developments in brain scanning techniques have shown that the posterior secondary cortex plays an extremely important part in the processing of pitch in the brain. In music, "pitch relation" is more important than pitch itself. A subset of five to seven pitches creates a scale. The scale tones are "not equivalent and are organized around a central tone, called the tonic".Time relations
Temporal organization of music is commonly referred to as "rhythm". In 1982 the neuroscientist Fraisse claimed that there are mainly two types of time relations that are fundamental to musical temporal organization: "the segmentation of an ongoing sequence into temporal groups" based on the duration values, and "extraction of an underlying temporal regularity or beat".In the brain, it is believed that the right hemisphere better handles meter, while the left hemisphere better handles rhythm. Scientists have studied patients with brain lesions in their right temporal auditory cortex and realized that they were unable to "tap a beat or generate a steady pulse".
Timbre
"Timbre" refers to the quality of a musical note that enables us to distinguish between different kinds of sound production. It is the characteristic of music that helps us recognize an instrument or source of a particular sound—such as a piano, saxophone, or a flute.Memory
Music unfolds over time, and therefore the "auditory cognitive system must depend to a large degree on mechanisms that allow a stimulus to be maintained on-line to be able to relate one element in a sequence to another that occurs later". Research has shown that working memory mechanisms for pitch information over a short period of time may be different from those involved in speech. In addition to the role that auditory cortices play in working memory for music, neuroimaging and lesion studies prove that frontal cortical areas also play an important role.Emotion
Music is not merely "limited to perception and memory", but is also closely related to emotion. The mode of music, and the tempo of a song can invoke joy or sorrow in the listener. In the brain, emotional analysis is carried out by "a common cortical relay, suggesting no direct access to subcortical, limbic structures".Musical disorders
[Image:Music Disorders.jpg|thumb|right|Music-specific disorders may be acquired or congenital]With a growing interest in music cognition amongst neuroscientists, music-specific disorders are becoming more relevant in research and in understanding music processing in the brain. Several music-specific disorders have been identified, with causes ranging from congenital to acquired.