Musical Perfect Pitch

Description

Perfect pitch, or absolute pitch (AP), is defined as the ability immediately and effortlessly to name a note or collection of notes when they are sounded. Often, persons with perfect pitch possess a memory capacity whereby they can remember the pitch of a note and the configuration of a group or series of notes after a significant interval of time has elapsed. These recognitive and memory talents involve a potential capacity for performing these functions together with a practice factor which is necessary for the maintenance of the skills at the highest level (summary by Profita and Bidder, 1988). Absolute pitch likely results from a combination of environmental and genetic factors (Theusch et al., 2009).

Clinical Features

Profita and Bidder (1988) studied 35 persons with perfect pitch, representing 19 families, with a questionnaire that provided information on note-recognition capacity and musical exposure and training, as well as demographic characteristics. The subjects were selected from the musical communities of 4 large metropolitan areas. Perfect pitch was found to predominate in females (24 of 35) and was detected at an early age. In 9 of the 19 families, only 1 individual had perfect pitch; there was uncertainty in 1 parent as to whether perfect pitch was present. In a second group of 7 families, 2 persons had perfect pitch. In 2 of the families, the 'affected' persons were a parent and child. In 4 of the instances in which the 'affected' persons were sibs, 1 parent was questionably 'affected.' In a third group of 3 families, 3 or more members, to a maximum of 5, were affected, and 2 generations were involved in all 3 instances. Of the 19 probands, 13 were female; of the 16 'secondary cases,' 11 were female. Profita and Bidder (1991) concluded that there was a strong correlation between the occurrence of perfect pitch and learning disabilities. (Profita, who studied piano and violin at the Juilliard School before turning to medicine, has perfect pitch.) See 191200 for a discussion of a form of lack of musical ability, tune deafness.

Schlaug et al. (1995) used high-resolution in vivo magnetic resonance morphometry of the planum temporale as an index of laterability in 30 healthy, right-handed professional musicians and compared the results with those from nonmusicians matched for age, sex, and handedness. They found that musicians with perfect pitch had stronger leftward planum temporale asymmetry than nonmusicians or musicians without perfect pitch. Positron emission tomography (PET) had demonstrated that the posterior superior temporal region, including the planum temporale, is involved in music perception. In the case of a musician with melody deafness after a circumscribed stroke, the lesion was centered on the left planum temporale. The left planum temporale includes the Wernicke area, the seat of language comprehension. The extreme leftward bias in musicians with perfect pitch may be related to the ability to make the verbal association in identifying a particular note or pitch.

Zatorre et al. (1998) used both structural and functional brain imaging techniques to investigate the neural basis of absolute pitch. Using PET scanning, they measured cerebral blood flow during the presentation of musical tones to AP possessors and to control musicians without AP. Listening to musical tones resulted in similar patterns of increased cerebral blood flow in auditory cortical areas in both groups, as expected. The AP group also demonstrated activation of the left posterior dorsolateral frontal cortex, an area thought to be related to learning conditional associations. However, a similar pattern of left dorsolateral frontal activity was also observed in non-AP subjects when they made relative pitch judgments of intervals, such as minor or major. Conversely, activities within the right inferior frontal cortex was observed in control but not in AP subjects during the interval-judgment task, suggesting that AP possessors need not access working memory mechanisms in this task. MRI measures of cortical volume indicated a larger left planum temporale in the AP group, which correlated with performance on a pitch-naming task. The findings suggested that AP may not be associated with a unique pattern of cerebral activity but rather may depend on the recruitment of a specialized network involved in the retrieval and manipulation of verbal-tonal associations.

By surveying more than 600 musicians in music conservatories, training programs, and orchestras, Baharloo et al. (1998) attempted to dissect the influences of early musical training and genetics on the development of absolute pitch. Early musical training appeared to be necessary but not sufficient for the development of absolute pitch. Forty percent of musicians who had begun training at 4 years of age or younger reported absolute pitch, whereas only 3% of those who had begun training at or after 9 years of age did so. Self-reported AP possessors were 4 times more likely to report another AP possessor in their families than were non-AP possessors. These data suggested that early musical training and genetic predisposition are needed for the development of AP.

Gregersen (1998) raised the question of whether AP is associated with other unusual cognitive abilities. He stated an informal impression that a subset of AP possessors also exhibit a high degree of mathematical and memory ability and that, in rare instances, they may exhibit unusual perceptual talents in other sensory realms, such as taste. He suggested that it might be 'interesting to ask whether there is a higher prevalence of AP among professional wine tasters or their first-degree relatives!' He pointed out that a small fraction of individuals with AP also experience strong color associations with particular pitches, a phenomenon that is termed synesthesia (612759). A number of composers apparently showed this phenomenon, including Sibelius and Scriabin (Profita and Bidder, 1988). Although synesthesia is very rare, it appears to exhibit strong familial aggregation (Baron-Cohen et al., 1996; Yoon, 1997). AP has been reported anecdotally in the setting of certain neurologic disorders, particularly autism and Williams syndrome (Sacks, 1995). A proportion of individuals with Williams syndrome (194050) are gifted musically, even in the face of significant mental disability.

Lenhoff et al. (2001) evaluated 5 patients with Williams syndrome for absolute musical pitch. The 5 patients had a mean IQ of 58 but were able to read musical notation. They began to play music at ages 5, 7, 8, 10, and 11 years, respectively. The 5 patients scored a mean near ceiling levels on all tests given: identifying single notes (97%), identifying notes in dyads and triads played harmonically together (98%), production of songs, including relative pitch and transposition of key (86%, mean lowered mainly by 1 patient who was confused by the task), and specific relative pitch tests of production (85%) and identification (89%). As a group, the 5 patients scored 97.5% on 1,084 absolute pitch trials, indicating that they possessed exceptional abilities in absolute pitch. By comparison, cognitively intact musicians who claim to have AP scored 84.3% on similar tests. Lenhoff et al. (2001) suggested that the prevalence of AP in individuals with Williams syndrome is higher than that in the general Western population (1 in 10,000), and noted that the age window of AP acquisition in Williams syndrome appears to be extended compared to the general population. The findings are important in the study of the genetics of pitch ability since individuals with Williams syndrome are genetically homogeneous. Hickok et al. (1995) reported that brain imaging of patients with Williams syndrome suggested an exaggerated left-right asymmetry of the planum temporale, which had also been found in musicians with absolute pitch (Schlaug et al., 1995), suggesting a neuroanatomic correlate to the ability.

Gregersen et al. (2013) found that 151 (20.1%) of 768 individuals with AP reported synesthesia. Associations between pitch and color were most common (84%), with fewer numbers of individuals having synesthesia involving smell, shapes, or other more complex sensory experiences. There was no difference in the prevalence of synesthesia between Caucasian and Asian AP individuals. The analysis yielded an OR of about 6.0 for synesthesia in AP individuals, suggesting these 2 cognitive traits are phenotypically and genetically related. In addition, 8 (22%) of 36 families with synesthesia reported a family member with AP. Gregersen et al. (2013) suggested that the association likely reflects a common neurodevelopmental mechanism of brain connectivity.

Inheritance

By formalized auditory testing of pitch perception of sibs of persons performing exceptionally well and of a control sample, Baharloo et al. (2000) demonstrated that absolute pitch, which the authors designated AP1, aggregates in families. They suggested that it may be possible to assemble a number of pedigrees of sib pairs sufficient to map loci for AP1.

Mapping

By genomewide linkage analysis of 73 multiplex AP families, Theusch et al. (2009) identified a candidate gene locus on chromosome 8q24.21 (SNP rs3057) in a subset of 45 families with European ancestry (exponential lod score of 3.464, empirical genomewide p value of 0.03). Other regions with suggestive lod scores included chromosomes 7q22.3, 8q21.11, and 9p21.3. Of these 4 regions, only the 7q22.3 linkage peak was also evident when 19 families with East Asian ancestry were analyzed separately. The findings indicated that AP is genetically heterogeneous.

By genomewide linkage analysis of 53 families with AP and 36 families with synesthesia, Gregersen et al. (2013) found evidence for a common locus on chromosome 6q14.1-q16.1 when combining the data for both disorders (nonparametric lod score of 4.68). There was also evidence for a more complex pattern of linkage on chromosome 2 (heterogeneity lod score of 4.7 at rs1482308) in the combined AP and synesthesia families. These findings provided genetic evidence that the 2 cognitive traits may be related. Sequencing the EPHA7 gene (602190), a candidate gene within the critical region on 6q, in 39 multiplex AP families showed that affected members of 4 families shared 1 or more of 3 nonsynonymous coding variants. One of these, N357S, was found in 2 Malaysian sibs with AP and was not present in the Exome Variant Project database, in 700 Asian controls, or in 400 European American controls.

Population Genetics

Gregersen et al. (1999) completed a survey of 2,707 music students at music conservatories as well as at the university and college music programs in the U.S. They observed large variations in AP prevalence among different student groups (range, 0% to 35%). There was a significant association between the type of institution or music program and the prevalence of AP in the students: conservatory had 24.6% with AP, university-based school of music had 7.3% with AP, and liberal arts/state university music program had 4.7% with AP. The authors also noted a strong correlation between the prevalence of AP and the percentage of students in these schools who reported their ethnic background as 'Asian or Pacific Islander' (r = 0.81, p less than 0.0001, Spearman rank correlation coefficient). This raised the possibility that AP is more prevalent in Asian students in general. In a specific study, they found that Asian students had a prevalence of 32.1% compared with a figure of 7.0% for all other ethnic groups combined. Furthermore, the high rate of AP in Asian students was observed in all types of educational institutions. As had been reported by others, Gregersen et al. (1999) observed a significant association between AP and the age at which an individual first began playing music. For the AP group as a whole, the mean age of starting musical activities was 5.4 +/- 2.8 years, whereas for the non-AP group the mean age was 7.9 +/- 13.2 years (p less than 0.0001). This trend was observed for Asian students as well as non-Asian students.

Gregersen et al. (2001) surveyed 1,067 music students enrolled in music theory classes in the United States and found an overall AP rate of 12.2%, with a markedly increased rate of AP in Asian students (47.5%) compared to Caucasian students (9.0%). Logistic regression analysis showed an increased rate of AP in the setting of earlier training, especially training based on 'fixed do' methods; however, in the absence of early training, the predicted probability of Asian music students having AP was 0.20 versus 0.03 among non-Asians. Early childhood training did not appear to influence AP rates among sibs of AP+ and AP- music students. Gregersen et al. (2001) concluded that existing data supported the view that certain early childhood musical exposures increase the probability of AP in genetically susceptible individuals.

Reanalyzing data from Gregersen et al. (2001), Henthorn and Deutsch (2007) stated that having spent early childhood in Asia appeared to be the significant differentiating factor in prevalence of AP and suggested that exposure to tonal language in infancy may predispose to the acquisition of AP. Gregersen et al. (2007) responded that full analysis of their data reveals that age of music training and exposure to 'fixed do' training before age 7 are the only factors that strongly predict the development of AP, in both Asians and Caucasians.