HOME

TheInfoList



OR:

Amusia is a musical disorder that appears mainly as a defect in processing pitch but also encompasses musical memory and recognition. Two main classifications of amusia exist: acquired amusia, which occurs as a result of
brain damage Neurotrauma, brain damage or brain injury (BI) is the destruction or degeneration of brain cells. Brain injuries occur due to a wide range of internal and external factors. In general, brain damage refers to significant, undiscriminating t ...
, and
congenital A birth defect, also known as a congenital disorder, is an abnormal condition that is present at birth regardless of its cause. Birth defects may result in disabilities that may be physical, intellectual, or developmental. The disabilities can ...
amusia, which results from a music-processing anomaly present since birth. Studies have shown that congenital amusia is a deficit in fine-grained pitch discrimination and that 4% of the population has this disorder. Acquired amusia may take several forms. Patients with brain damage may experience the loss of ability to produce musical sounds while sparing
speech Speech is a human vocal communication using language. Each language uses phonetic combinations of vowel and consonant sounds that form the sound of its words (that is, all English words sound different from all French words, even if they are th ...
, much like aphasics lose speech selectively but can sometimes still
sing Singing is the act of creating musical sounds with the voice. A person who sings is called a singer, artist or vocalist (in jazz and/or popular music). Singers perform music (arias, recitatives, songs, etc.) that can be sung with or without ...
. Other forms of amusia may affect specific sub-processes of music processing. Current research has demonstrated dissociations between
rhythm Rhythm (from Greek , ''rhythmos'', "any regular recurring motion, symmetry") generally means a " movement marked by the regulated succession of strong and weak elements, or of opposite or different conditions". This general meaning of regular re ...
melody A melody (from Greek μελῳδία, ''melōidía'', "singing, chanting"), also tune, voice or line, is a linear succession of musical tones that the listener perceives as a single entity. In its most literal sense, a melody is a combina ...
and emotional processing of music. Amusia may include impairment of any combination of these skill sets.


Signs and symptoms

Symptoms of amusia are generally categorized as receptive, clinical, or mixed. Symptoms of receptive amusia, sometimes referred to as "musical deafness" or "tone deafness", include the inability to recognize familiar
melodies A melody (from Greek μελῳδία, ''melōidía'', "singing, chanting"), also tune, voice or line, is a linear succession of musical tones that the listener perceives as a single entity. In its most literal sense, a melody is a combinati ...
, the loss of ability to read
musical notation Music notation or musical notation is any system used to visually represent aurally perceived music played with instruments or sung by the human voice through the use of written, printed, or otherwise-produced symbols, including notation f ...
, and the inability to detect wrong or out-of tune notes.http://amusia-brain.blogspot.com/2008/02/definition_25.html Hutchings, Tiffany, Seth Hayden, Mandy Politziner, and Erina Kainuma. "Amusia." Web log post. Amusia: Definition, Welcome to Amusia..., Congenital and Acquired Amusia, Neural Overview. 25 February 2008. Web. 10 October 2009. Clinical, or expressive, symptoms include the loss of ability to sing, write
musical notation Music notation or musical notation is any system used to visually represent aurally perceived music played with instruments or sung by the human voice through the use of written, printed, or otherwise-produced symbols, including notation f ...
, and/or play an instrument. A mixed disorder is a combination of expressive and receptive impairment. Clinical symptoms of acquired amusia are much more variable than those of congenital amusia and are determined by the location and nature of the lesion. Brain injuries may affect motor or expressive functioning, including the ability to sing, whistle, or hum a tune (oral-expressive amusia), the ability to play an instrument (instrumental amusia or musical apraxia), and the ability to write music (musical agraphia). Additionally, brain damage to the receptive dimension affects the faculty to discriminate tunes (receptive or sensorial amusia), the ability to read music (musical alessia), and the ability to identify songs that were familiar prior to the brain damage (amnesic amusia). Research suggests that patients with amusia also have difficulty when it comes to spatial processing. Amusics performed more quickly than normal individuals on a combined task of both spatial and musical processing tasks, which is most likely due to their deficit. Normal individuals experience interference due to their intact processing of both musical and spatial tasks, while amusics do not. Pitch processing normally depends on the cognitive mechanisms that are usually used to process spatial representations. Those with congenital amusia show impaired performance on discrimination, identification and imitation of sentences with intonational differences in pitch direction in their final word. This suggests that amusia can in subtle ways impair language processing.


Social and emotional

Amusic individuals have a remarkable sparing of emotional responses to music in the context of severe and lifelong deficits in processing music. Some individuals with amusia describe music as unpleasant. Others simply refer to it as noise and find it annoying. This can have social implications because amusics often try to avoid music, which in many social situations is not an option. In China and other countries where
tonal languages Tone is the use of pitch in language to distinguish lexical or grammatical meaning – that is, to distinguish or to inflect words. All verbal languages use pitch to express emotional and other paralinguistic information and to convey emph ...
are spoken, amusia may have a more pronounced social and emotional impact: difficulty in speaking and understanding the language. However, context clues are often strong enough to determine the correct meaning, similarly to how
homophone A homophone () is a word that is pronounced the same (to varying extent) as another word but differs in meaning. A ''homophone'' may also differ in spelling. The two words may be spelled the same, for example ''rose'' (flower) and ''rose'' (pa ...
s can be understood.


Related diseases

Amusia has been classified as a learning disability that affects musical abilities. Research suggests that in congenital amusia, younger subjects can be taught tone differentiation techniques. This finding leads researchers to believe that amusia is related to
dyslexia Dyslexia, also known until the 1960s as word blindness, is a disorder characterized by reading below the expected level for one's age. Different people are affected to different degrees. Problems may include difficulties in spelling words, r ...
and other similar disorders. Research has been shown that amusia may be related to an increase in size of the
cerebral cortex The cerebral cortex, also known as the cerebral mantle, is the outer layer of neural tissue of the cerebrum of the brain in humans and other mammals. The cerebral cortex mostly consists of the six-layered neocortex, with just 10% consisting o ...
, which may be a result of a malformation in cortical development. Conditions such as dyslexia and
epilepsy Epilepsy is a group of non-communicable neurological disorders characterized by recurrent epileptic seizures. Epileptic seizures can vary from brief and nearly undetectable periods to long periods of vigorous shaking due to abnormal electrica ...
are due to a malformation in cortical development and also lead to an increase in cortical thickness, which leads researchers to believe that congenital amusia may be caused by the identical phenomenon in a different area of the brain. Amusia is also similar to
aphasia Aphasia is an inability to comprehend or formulate language because of damage to specific brain regions. The major causes are stroke and head trauma; prevalence is hard to determine but aphasia due to stroke is estimated to be 0.1–0.4% in ...
in that they affect similar areas of the
brain A brain is an organ (biology), organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It is located in the head, usually close to the sensory organs for senses such as Visual perception, vision. I ...
near the
temporal lobe The temporal lobe is one of the four major lobes of the cerebral cortex in the brain of mammals. The temporal lobe is located beneath the lateral fissure on both cerebral hemispheres of the mammalian brain. The temporal lobe is involved i ...
. Most cases of those with amusia do not show any symptoms of aphasia. However, a number of cases have shown that those who have aphasia can exhibit symptoms of amusia, especially in acquired aphasia. The two are not mutually exclusive and having one does not imply possession of the other. In acquired amusia, inability to perceive music correlates with an inability to perform other higher-level functions. In this case, as musical ability improves, so too do the higher cognitive functions which suggests that musical ability is closely related to these higher-level functions, such as
memory Memory is the faculty of the mind by which data or information is encoded, stored, and retrieved when needed. It is the retention of information over time for the purpose of influencing future action. If past events could not be remember ...
and
learning Learning is the process of acquiring new understanding, knowledge, behaviors, skills, values, attitudes, and preferences. The ability to learn is possessed by humans, animals, and some machines; there is also evidence for some kind of lea ...
, mental flexibility, and semantic fluency. Amusia can also be related to
aprosody Aprosodia is a neurological condition characterized by the inability of a person to properly convey or interpret emotional prosody. Prosody in language refers to the ranges of rhythm, pitch, stress, intonation, etc. These neurological deficits can ...
, a disorder in which the person's speech is affected, becoming extremely monotonous. It has been found that both amusia and aprosody can arise from seizures occurring in the non-dominant hemisphere. They can also both arise from lesions to the brain, as can Broca's aphasia come about simultaneously with amusia from injury. There is a relation between musical abilities and the components of speech; however, it is not understood very well.


Diagnosis

The diagnosis of amusia requires multiple investigative tools all described in the Montreal Protocol for Identification of Amusia. This protocol has at its center the Montreal Battery of Evaluation of Amusia (MBEA), which involves a series of tests that evaluate the use of musical characteristics known to contribute to the memory and perception of conventional music, but the protocol also allow for the ruling out of other conditions that can explain the clinical signs observed. The battery comprises six subtests which assess the ability to discriminate
pitch contour __NOTOC__ In linguistics, speech synthesis, and music, the pitch contour of a sound is a function or curve that tracks the perceived pitch of the sound over time. Pitch contour may include multiple sounds utilizing many pitches, and can relate t ...
,
musical scales In music theory, a scale is any set of musical notes ordered by fundamental frequency or pitch. A scale ordered by increasing pitch is an ascending scale, and a scale ordered by decreasing pitch is a descending scale. Often, especially in the ...
, pitch intervals, rhythm,
meter The metre (British spelling) or meter (American spelling; see spelling differences) (from the French unit , from the Greek noun , "measure"), symbol m, is the primary unit of length in the International System of Units (SI), though its pref ...
, and memory. An individual is considered amusic if they perform two
standard deviations In statistics, the standard deviation is a measure of the amount of variation or dispersion of a set of values. A low standard deviation indicates that the values tend to be close to the mean (also called the expected value) of the set, while ...
below the mean obtained by musically competent controls. This musical pitch disorder represents a phenotype that serves to identify the associated neuro-genetic factors. Both MRI-based brain structural analyses and electroencephalography (EEG) are common methods employed to uncover brain anomalies associated with amusia (See
Neuroanatomy Neuroanatomy is the study of the structure and organization of the nervous system. In contrast to animals with radial symmetry, whose nervous system consists of a distributed network of cells, animals with bilateral symmetry have segregated, defi ...
). Additionally,
voxel-based morphometry Voxel-based morphometry is a computational approach to neuroanatomy that measures differences in local concentrations of brain tissue, through a voxel-wise comparison of multiple brain images. In traditional morphometry, volume of the whole br ...
(VBM) is used to detect anatomical differences between the MRIs of amusic brains and musically intact brains, specifically with respect increased and/or decreased amounts of white and grey matter.


Classifications

There are two general classifications of amusia: congenital amusia and acquired amusia.


Congenital amusia

Congenital amusia, commonly known as tone deafness, refers to a musical disability that cannot be explained by prior brain lesion, hearing loss, cognitive defects, or lack of environmental stimulation, and it affects about 4% of the population. Individuals with congenital amusia seem to lack the musical predispositions with which most people are born. They are unable to recognize or hum familiar tunes even if they have normal
audiometry Audiometry () is a branch of audiology and the science of measuring hearing acuity for variations in sound intensity and pitch and for tonal purity, involving thresholds and differing frequencies. Typically, audiometric tests determine a subje ...
and above-average intellectual and memory skills. Also, they do not show sensitivity to dissonant chords in a melodic context, which, as discussed earlier, is one of the musical predispositions exhibited by infants. The hallmark of congenital amusia is a deficit in fine-grained pitch discrimination, and this deficit is most apparent when congenital amusics are asked to pick out a wrong note in a given melody. If the distance between two successive pitches is small, congenital amusics are not able to detect a pitch change. As a result of this defect in pitch perception, a lifelong musical impairment may emerge due to a failure to internalize musical scales. A lack of fine-grained pitch discrimination makes it extremely difficult for amusics to enjoy and appreciate music, which consists largely of small pitch changes. Tone-deaf people seem to be disabled only when it comes to music as they can fully interpret the prosody or intonation of human speech. Tone deafness has a strong negative
correlation In statistics, correlation or dependence is any statistical relationship, whether causal or not, between two random variables or bivariate data. Although in the broadest sense, "correlation" may indicate any type of association, in statistic ...
with belonging to societies with
tonal language Tone is the use of pitch in language to distinguish lexical or grammatical meaning – that is, to distinguish or to inflect words. All verbal languages use pitch to express emotional and other paralinguistic information and to convey emph ...
s. This could be evidence that the ability to reproduce and distinguish between notes may be a learned skill; conversely, it may suggest that the genetic predisposition towards accurate pitch discrimination may influence the linguistic development of a population towards tonality. A correlation between allele frequencies and linguistic typological features has been recently discovered, supporting the latter hypothesis. Tone deafness is also associated with other musical-specific impairments such as the inability to keep time with music ( beat deafness, or the lack of
rhythm Rhythm (from Greek , ''rhythmos'', "any regular recurring motion, symmetry") generally means a " movement marked by the regulated succession of strong and weak elements, or of opposite or different conditions". This general meaning of regular re ...
), or the inability to remember or recognize a song. These disabilities can appear separately, but some research shows that they are more likely to appear in tone-deaf people. Experienced musicians, such as
W. A. Mathieu William Allaudin Mathieu (born 1937) is a composer, pianist, choir director, music teacher, and author. He began studying piano at the age of six, and began recording his music and compositions in the 1970s on his record label, Cold Mountain Music. ...
, have addressed tone deafness in adults as correctable with training.


Acquired amusia

Acquired amusia is a musical disability that shares the same characteristics as congenital amusia, but rather than being inherited, it is the result of brain damage. It is also more common than congenital amusia. While it has been suggested that music is processed by music-specific neural networks in the brain, this view has been broadened to show that music processing also encompasses generic cognitive functions, such as memory, attention, and executive processes. A study was published in 2009 which investigated the neural and cognitive mechanisms that underlie acquired amusia and contribute to its recovery. The study was performed on 53 stroke patients with a left or right hemisphere
middle cerebral artery The middle cerebral artery (MCA) is one of the three major paired cerebral arteries that supply blood to the cerebrum. The MCA arises from the internal carotid artery and continues into the lateral sulcus where it then branches and projects to ma ...
(MCA) infarction one week, three months, and six months after the stroke occurred. Amusic subjects were identified one week following their stroke, and over the course of the study, amusics and non-amusics were compared in both brain lesion location and their performances on neuropsychological tests. Results showed that there was no significant difference in the distribution of left and right hemisphere lesions between amusic and non-amusic groups, but that the amusic group had a significantly higher number of lesions to the
frontal lobe The frontal lobe is the largest of the four major lobes of the brain in mammals, and is located at the front of each cerebral hemisphere (in front of the parietal lobe and the temporal lobe). It is parted from the parietal lobe by a groove be ...
and
auditory cortex The auditory cortex is the part of the temporal lobe that processes auditory information in humans and many other vertebrates. It is a part of the auditory system, performing basic and higher functions in hearing, such as possible relations to ...
.
Temporal lobe The temporal lobe is one of the four major lobes of the cerebral cortex in the brain of mammals. The temporal lobe is located beneath the lateral fissure on both cerebral hemispheres of the mammalian brain. The temporal lobe is involved i ...
lesions were also observed in patients with amusia. Amusia is a common occurrence following an
ischemic Ischemia or ischaemia is a restriction in blood supply to any tissue, muscle group, or organ of the body, causing a shortage of oxygen that is needed for cellular metabolism (to keep tissue alive). Ischemia is generally caused by problems w ...
MCA stroke, as evidenced by the 60% of patients who were found to be amusic at the one-week post-stroke stage. While significant recovery takes place over time, amusia can persist for long periods of time. Test results suggest that acquired amusia and its recovery in the post-stroke stage are associated with a variety of cognitive functions, particularly attention, executive functioning and working memory.


Neuroanatomy

Neurologically intact individuals appear to be born musical. Even before they are able to talk, infants show remarkable musical abilities that are similar to those of adults in that they are sensitive to
musical scale In music theory, a scale is any set of musical notes ordered by fundamental frequency or pitch. A scale ordered by increasing pitch is an ascending scale, and a scale ordered by decreasing pitch is a descending scale. Often, especially in the ...
s and a regular
tempo In musical terminology, tempo ( Italian, 'time'; plural ''tempos'', or ''tempi'' from the Italian plural) is the speed or pace of a given piece. In classical music, tempo is typically indicated with an instruction at the start of a piece (ofte ...
. Also, infants are able to differentiate between consonant and dissonant intervals. These perceptual skills indicate that music-specific predispositions exist. Prolonged exposure to music develops and refines these skills. Extensive musical training does not seem to be necessary in the processing of
chords Chord may refer to: * Chord (music), an aggregate of musical pitches sounded simultaneously ** Guitar chord a chord played on a guitar, which has a particular tuning * Chord (geometry), a line segment joining two points on a curve * Chord ( ...
and
keys Key or The Key may refer to: Common meanings * Key (cryptography), a piece of information that controls the operation of a cryptography algorithm * Key (lock), device used to control access to places or facilities restricted by a lock * Key (m ...
. The development of musical competence most likely depends on the encoding of pitch along musical scales and maintaining a regular
pulse In medicine, a pulse represents the tactile arterial palpation of the cardiac cycle (heartbeat) by trained fingertips. The pulse may be palpated in any place that allows an artery to be compressed near the surface of the body, such as at the n ...
, both of which are key components in the structure of music and aid in perception, memory, and performance. Also, the encoding of pitch and temporal regularity are both likely to be specialized for music processing. Pitch perception is absolutely crucial to processing music. The use of scales and the organization of scale tones around a central tone (called the tonic) assign particular importance to notes in the scale and cause non-scale notes to sound out of place. This enables the listener to ascertain when a wrong note is played. However, in individuals with amusia, this ability is either compromised or lost entirely. Music-specific neural networks exist in the brain for a variety of music-related tasks. It has been shown that
Broca's area Broca's area, or the Broca area (, also , ), is a region in the frontal lobe of the dominant hemisphere, usually the left, of the brain with functions linked to speech production. Language processing has been linked to Broca's area since Pier ...
is involved in the processing of musical syntax. Furthermore, brain damage can disrupt an individual's ability to tell the difference between tonal and
atonal Atonality in its broadest sense is music that lacks a tonal center, or key. ''Atonality'', in this sense, usually describes compositions written from about the early 20th-century to the present day, where a hierarchy of harmonies focusing on a s ...
music and detect the presence of wrong notes, but can preserve the individual's ability to assess the distance between pitches and the direction of the pitch. The opposite scenario can also occur, in which the individual loses pitch discrimination capabilities, but can sense and appreciate the tonal context of the work. Distinct neural networks also exist for music memories, singing, and music recognition. Neural networks for music recognition are particularly intriguing. A patient can undergo brain damage that renders them unable to recognize familiar melodies that are presented without words. However, the patient maintains the ability to recognize spoken lyrics or words, familiar voices, and environmental sounds. The reverse case is also possible, in which the patient cannot recognize spoken words, but can still recognize familiar melodies. These situations overturn previous claims that speech recognition and music recognition share a single processing system. Instead, it is clear that there are at least two distinct processing modules: one for speech and one for music. Many research studies of individuals with amusia show that a number of cortical regions appear to be involved in processing music. Some report that the
primary auditory cortex The auditory cortex is the part of the temporal lobe that processes auditory information in humans and many other vertebrates. It is a part of the auditory system, performing basic and higher functions in hearing, such as possible relations ...
, secondary auditory cortex, and
limbic system The limbic system, also known as the paleomammalian cortex, is a set of brain structures located on both sides of the thalamus, immediately beneath the medial temporal lobe of the cerebrum primarily in the forebrain.Schacter, Daniel L. 2012. ''P ...
are responsible for this faculty, while more recent studies suggest that lesions in other cortical areas, abnormalities in cortical thickness, and deficiency in neural connectivity and brain plasticity may contribute to amusia. While various causes of amusia exist, some general findings that provide insight to the brain mechanisms involved in music processing are discussed below.


Pitch relations

Studies suggest that the analysis of pitch is primarily controlled by the right temporal region of the brain. The right secondary auditory cortex processes pitch change and manipulation of fine tunes; specifically, this region distinguishes the multiple pitches that characterize melodic tunes as contour (pitch direction) and interval (frequency ratio between successive notes) information. The right superior temporal gyrus recruits and evaluates contour information, while both right and left temporal regions recruit and evaluate interval information. In addition, the right anterolateral part of Heschl's gyrus (primary auditory cortex) is also concerned with processing pitch information.


Temporal relations

The brain analyzes the temporal (rhythmic) components of music in two ways: (1) it segments the ongoing sequences of music into temporal events based on duration, and (2) it groups those temporal events to understand the underlying beat to music. Studies on rhythmic discrimination reveal that the right temporal auditory cortex is responsible for temporal segmenting, and the left temporal auditory cortex is responsible for temporal grouping. Other studies suggest the participation of motor cortical areas in rhythm perception and production. Therefore, a lack of involvement and networking between bilateral temporal cortices and neural motor centers may contribute to both congenital and acquired amusia.


Memory

Memory is required in order to process and integrate both melodic and rhythmic aspects of music. Studies suggest that there is a rich interconnection between the right temporal gyrus and frontal cortical areas for working memory in music appreciation. This connection between the temporal and frontal regions of the brain is extremely important since these regions play critical roles in music processing. Changes in the temporal areas of the amusic brain are most likely associated with deficits in pitch perception and other musical characteristics, while changes in the frontal areas are potentially related to deficits in cognitive processing aspects, such as memory, that are needed for musical discrimination tasks. Memory is also concerned with the recognition and internal representation of tunes, which help to identify familiar songs and confer the ability to sing tunes in one's head. The activation of the superior temporal region and left inferior temporal and frontal areas is responsible for the recognition of familiar songs, and the right auditory cortex (a perceptual mechanism) is involved in the internal representation of tunes. These findings suggest that any abnormalities and/or injuries to these regions of the brain could facilitate amusia.


Other regions of the brain possibly linked to amusia

* Lesions in (or the absence of) associations between the right temporal lobe and inferior frontal lobe. In nine of ten tone-deaf people, the superior
arcuate fasciculus The arcuate fasciculus (AF) is a bundle of axons that generally connects the Broca's area and the Wernicke's area in the brain. It is an association fiber tract connecting caudal temporal cortex and inferior frontal lobe. ''Fasciculus arcuatus' ...
in the right hemisphere could not be detected, suggesting a disconnection between the posterior superior temporal gyrus and the posterior inferior frontal gyrus. Researchers suggested the posterior superior temporal gyrus was the origin of the disorder. * Cortical thickness and reduced
white matter White matter refers to areas of the central nervous system (CNS) that are mainly made up of myelinated axons, also called tracts. Long thought to be passive tissue, white matter affects learning and brain functions, modulating the distribu ...
– in a recent study,
voxel-based morphometry Voxel-based morphometry is a computational approach to neuroanatomy that measures differences in local concentrations of brain tissue, through a voxel-wise comparison of multiple brain images. In traditional morphometry, volume of the whole br ...
, an imaging technique used to explore structural differences in the brain, revealed a decrease in white matter concentration in the right
inferior frontal gyrus The inferior frontal gyrus (IFG), (gyrus frontalis inferior), is the lowest positioned gyrus of the frontal gyri, of the frontal lobe, and is part of the prefrontal cortex. Its superior border is the inferior frontal sulcus (which divides it f ...
of amusic individuals as compared to controls. Lack of extensive exposure to music could be a contributing factor to this white matter reduction. For example, amusic individuals may be less inclined to listen to music than others, which could ultimately cause reduced
myelination Myelin is a lipid-rich material that surrounds nerve cell axons (the nervous system's "wires") to insulate them and increase the rate at which electrical impulses (called action potentials) are passed along the axon. The myelinated axon can be ...
of connections to the frontal areas of the brain. * Involvement of the parahippocampal gyrus (responsible for the emotional reaction to music)


Treatment

Currently, no forms of treatment have proven effective in treating amusia. One study has shown tone differentiation techniques to have some success; however, future research on treatment of this disorder will be necessary to verify this technique as an appropriate treatment.


History

In 1825, F. Gall mentioned a "musical organ" in a specific region of the human brain that could be spared or disrupted after a traumatic event resulting in brain damage. In 1865,
Jean-Baptiste Bouillaud Jean-Baptiste Bouillaud (16 September 1796 – 29 October 1881) was a French physician born in Bragette, now part of Garat, Charente. Bouillaud was an early advocate of the localization of cerebral functions (especially of speech). He received ...
described the first series of cases that involved the loss of music abilities that were due to brain injury. In 1878,
Grant Allen Charles Grant Blairfindie Allen (February 24, 1848 – October 25, 1899) was a Canadian science writer and novelist, educated in England. He was a public promoter of evolution in the second half of the nineteenth century. Biography Early life a ...
was the first to describe in the medical literature what would later be termed congenital amusia, calling it "note-deafness". Later, during the late nineteenth century, several influential neurologists studied language in an attempt to construct a theory of cognition. While not studied as thoroughly as language, music and visual processing were also studied. In 1888–1890, August Knoblauch produced a cognitive model for music processing and termed it amusia. This model for music processing was the earliest produced. While the possibility that certain individuals may be born with musical deficits is not a new notion, the first documented case of congenital amusia was published only in 2002. The study was conducted with a female volunteer, referred to as Monica, who declared herself to be musically impaired in response to an advertisement in the newspaper. Monica had no psychiatric or neurological history, nor did she have any hearing loss. MRI scans showed no abnormalities. Monica also scored above average on a standard intelligence test, and her working memory was evaluated and found to be normal. However, Monica had a lifelong inability to recognize or perceive music, which had persisted even after involvement with music through church choir and band during her childhood and teenage years. Monica said that she does not enjoy listening to music because, to her, it sounded like noise and evoked a stressful response. In order to determine if Monica's disorder was amusia, she was subjected to the MBEA series of tests. One of the tests dealt with Monica's difficulties in discriminating pitch variations in sequential notes. In this test, a pair of melodies was played, and Monica was asked if the second melody in the pair contained a wrong note. Monica's score on this test was well below the average score generated by the control group. Further tests showed that Monica struggled with recognizing highly familiar melodies, but that she had no problems in recognizing the voices of well-known speakers. Thus, it was concluded that Monica's deficit seemed limited to music. A later study showed that not only do amusics experience difficulty in discriminating variations in pitch, but they also exhibit deficits in perceiving patterns in pitch. This finding led to another test that was designed to assess the presence of a deficiency in pitch perception. In this test, Monica heard a sequence of five piano tones of constant pitch followed by a comparison sequence of five piano tones in which the fourth tone could be the same pitch as the other notes in the sequence or a completely different pitch altogether. Monica was asked to respond "yes" if she detected a pitch change on the fourth tone or respond "no" if she could not detect a pitch change. Results showed that Monica could barely detect a pitch change as large as two
semitone A semitone, also called a half step or a half tone, is the smallest musical interval commonly used in Western tonal music, and it is considered the most dissonant when sounded harmonically. It is defined as the interval between two adjacent no ...
s (
whole tone In Western music theory, a major second (sometimes also called whole tone or a whole step) is a second spanning two semitones (). A second is a musical interval encompassing two adjacent staff positions (see Interval number for more det ...
), or half steps. While this pitch-processing deficit is extremely severe, it does not seem to include speech intonation. This is because pitch variations in speech are very coarse compared with those used in music. In conclusion, Monica's learning disability arose from a basic problem in pitch discrimination, which is viewed as the origin of congenital amusia.


Research

Over the past decade, much has been discovered about amusia. However, there remains a great deal more to learn. While a method of treatment for people with amusia has not been defined, tone differentiation techniques have been used on amusic patients with some success. It was found with this research that children reacted positively to these tone differentiation techniques, while adults found the training annoying. However, further research in this direction would aid in determining if this would be a viable treatment option for people with amusia. Additional research can also serve to indicate which processing component in the brain is essential for normal music development. Also, it would be extremely beneficial to investigate musical learning in relation to amusia since this could provide valuable insights into other forms of learning disabilities such as
dysphasia Aphasia is an inability to comprehend or formulate language because of damage to specific brain regions. The major causes are stroke and head trauma; prevalence is hard to determine but aphasia due to stroke is estimated to be 0.1–0.4% in th ...
and dyslexia.


Notable cases


In fiction

*
Horatio Hornblower Horatio Hornblower is a fictional officer in the British Royal Navy during the Napoleonic Wars, the protagonist of a series of novels and stories by C. S. Forester. He later became the subject of films, radio and television programmes, an ...
* Grace from ''
Home on the Range "Home on the Range" is a classic cowboy song, sometimes called the "unofficial anthem" of the American West. Dr. Brewster M. Higley (also spelled Highley) of Smith County, Kansas, wrote the lyrics as the poem "My Western Home" in 1872 or 1873 ...
'' * James Fraser from '' Outlander'' by
Diana Gabaldon Diana J. Gabaldon (; born January 11, 1952) is an American author, known for the ''Outlander'' series of novels. Her books merge multiple genres, featuring elements of historical fiction, romance, mystery, adventure and science fiction/fantas ...
* Rodrigo from ''
Mozart in the Jungle ''Mozart in the Jungle'' is an American comedy-drama streaming television series developed by Roman Coppola, Jason Schwartzman, Alex Timbers, and Paul Weitz for the video-on-demand service Amazon Prime Video. It received a production order in ...
''


See also

*
Absolute pitch Absolute pitch (AP), often called perfect pitch, is a rare ability of a person to identify or re-create a given musical note without the benefit of a reference tone. AP may be demonstrated using linguistic labeling ("naming" a note), associating ...
, the human ability to name a musical note when played or sung (less common than relative pitch) *
Auditory agnosia Auditory agnosia is a form of agnosia that manifests itself primarily in the inability to recognize or differentiate between sounds. It is not a defect of the ear or "hearing", but rather a neurological inability of the brain to process sound meani ...
* Cognitive neuroscience of music *
Color blindness Color blindness or color vision deficiency (CVD) is the decreased ability to see color or differences in color. It can impair tasks such as selecting ripe fruit, choosing clothing, and reading traffic lights. Color blindness may make some aca ...
*
Musical aptitude Music psychology, or the psychology of music, may be regarded as a branch of both psychology and musicology. It aims to explain and understand musical behaviour and experience, including the processes through which music is perceived, created, res ...
* Music-specific disorders * Relative pitch, the human ability to accurately distinguish pitch intervals (more common than absolute pitch) *
Synesthesia Synesthesia (American English) or synaesthesia (British English) is a perceptual phenomenon in which stimulation of one sensory or cognitive pathway leads to involuntary experiences in a second sensory or cognitive pathway. People who re ...
* Tonal memory


References


Further reading

* *


External links

* MedicineNet
Amusia
* NIH
Distorted Tunes Test
* The Listening Book

by
W. A. Mathieu William Allaudin Mathieu (born 1937) is a composer, pianist, choir director, music teacher, and author. He began studying piano at the age of six, and began recording his music and compositions in the 1970s on his record label, Cold Mountain Music. ...
{{Pitch (music) Agnosia Music cognition Music psychology Communication disorders Hearing