Dominique T. Vuvan

Prevalence of congenital amusia

Congenital amusia (commonly known as tone deafness) is a lifelong musical disorder that affects 4% of the population according to a single estimate based on a single test from 1980. Here we present the first large-based measure of prevalence with a sample of 20 000 participants, which does not rely on self-referral. On the basis of three objective tests and a questionnaire, we show that (a) the prevalence of congenital amusia is only 1.5%, with slightly more females than males, unlike other developmental disorders where males often predominate; (b) self-disclosure is a reliable index of congenital amusia, which suggests that congenital amusia is hereditary, with 46% first-degree relatives similarly affected; (c) the deficit is not attenuated by musical training and (d) it emerges in relative isolation from other cognitive disorder, except for spatial orientation problems. Hence, we suggest that congenital amusia is likely to result from genetic variations that affect musical abilities specifically.

Tonal hierarchy representations in auditory imagery

Two experiments investigated psychological representations of musical tonality in auditory imagery. In Experiment 1, musically trained participants heard a single tone as a perceptual cue and built an auditory image of a specified major tonality based on that cue; participants’ images were then assessed using judgments of probe tones. In Experiment 2 participants imaged a minor tonality rather than a major one. Analysis of the probe tone ratings indicated that participants successfully imaged both major and minor tonal hierarchies, demonstrating that auditory imagery functions comparably to auditory perception. In addition, the strength of the major tonal image was dependent upon the pitch and tonal relations of the perceptual cue and the to-be-imaged tonality. Finally, representations of minor tonal hierarchies were less robust than those of major ones, converging with perceptual evidence that minor tonalities are less psychologically stable than major tonalities.

Activation in the Right Inferior Parietal Lobule Reflects the Representation of Musical Structure beyond Simple Pitch Discrimination

Pitch discrimination tasks typically engage the superior temporal gyrus and the right inferior frontal gyrus. It is currently unclear whether these regions are equally involved in the processing of incongruous notes in melodies, which requires the representation of musical structure (tonality) in addition to pitch discrimination. To this aim, 14 participants completed two tasks while undergoing functional magnetic resonance imaging, one in which they had to identify a pitch change in a series of non-melodic repeating tones and a second in which they had to identify an incongruous note in a tonal melody. In both tasks, the deviants activated the right superior temporal gyrus. A contrast between deviants in the melodic task and deviants in the non-melodic task (melodic > non-melodic) revealed additional activity in the right inferior parietal lobule. Activation in the inferior parietal lobule likely represents processes related to the maintenance of tonal pitch structure in working memory during pitch discrimination.

Effects of vocal training in a musicophile with congenital amusia

ABSTRACT Congenital amusia is a condition in which an individual suffers from a deficit of musical pitch perception and production. Individuals suffering from congenital amusia generally tend to abstain from musical activities. Here, we present the unique case of Tim Falconer, a self-described musicophile who also suffers from congenital amusia. We describe and assess Tim’s attempts to train himself out of amusia through a self-imposed 18-month program of formal vocal training and practice. We tested Tim with respect to music perception and vocal production across seven sessions including pre- and post-training assessments. We also obtained diffusion-weighted images of his brain to assess connectivity between auditory and motor planning areas via the arcuate fasciculus (AF). Tim’s behavioral and brain data were compared to that of normal and amusic controls. While Tim showed temporary gains in his singing ability, he did not reach normal levels, and these gains faded when he was not engaged in regular lessons and practice. Tim did show some sustained gains with respect to the perception of musical rhythm and meter. We propose that Tim’s lack of improvement in pitch perception and production tasks is due to long-standing and likely irreversible reduction in connectivity along the AF fiber tract.

The Montreal Protocol for Identification of Amusia

The Montreal Battery for the Evaluation of Amusia (MBEA; Peretz, Champod, & Hyde Annals of the New York Academy of Sciences, 999, 58–75, 2003) is an empirically grounded quantitative tool that is widely used to identify individuals with congenital amusia. The use of such a standardized measure ensures that the individuals tested will conform to a specific neuropsychological profile, allowing for comparisons across studies and research groups. Recently, a number of researchers have published credible critiques of the usefulness of the MBEA as a diagnostic tool for amusia. Here we argue that the MBEA and its online counterpart, the AMUSIA tests (Peretz et al. Music Perception, 25, 331–343, 2008), should be considered steps in a screening process for amusia, rather than standalone diagnostic tools. The goal of this article is to present, in detailed and easily replicable format, the full protocol through which congenital amusics should be identified. In providing information that has often gone unreported in published articles, we aim to clarify the strengths and limitations of the MBEA and to make recommendations for its continued use by the research community as part of the Montreal Protocol for Identification of Amusia.

Pre-target neural oscillations predict variability in the detection of small pitch changes

Pitch discrimination is important for language or music processing. Previous studies indicate that auditory perception depends on pre-target neural activity. However, so far the pre-target electrophysiological conditions which enable the detection of small pitch changes are not well studied, but might yield important insights into pitch-processing. We used magnetoencephalography (MEG) source imaging to reveal the pre-target effects of successful auditory detection of small pitch deviations from a sequence of standard tones. Participants heard a sequence of four pure tones and had to determine whether the last target tone was different or identical to the first three standard sounds. We found that successful pitch change detection could be predicted from the amplitude of theta (4–8 Hz) oscillatory activity in the right inferior frontal gyrus (IFG) as well as beta (12–30 Hz) oscillatory activity in the right auditory cortex. These findings confirm and extend evidence for the involvement of theta as well as beta-band activity in auditory perception.

Random feedback makes listeners tone-deaf

The mental representation of pitch structure (tonal knowledge) is a core component of musical experience and is learned implicitly through exposure to music. One theory of congenital amusia (tone deafness) posits that conscious access to tonal knowledge is disrupted, leading to a severe deficit of music cognition. We tested this idea by providing random performance feedback to neurotypical listeners while they listened to melodies for tonal incongruities and had their electrical brain activity monitored. The introduction of random feedback was associated with a reduction of accuracy and confidence, and a suppression of the late positive brain response usually elicited by conscious detection of a tonal violation. These effects mirror the behavioural and neurophysiological profile of amusia. In contrast, random feedback was associated with an increase in the amplitude of the early right anterior negativity, possibly due to heightened attention to the experimental task. This successful simulation of amusia in a normal brain highlights the key role of feedback in learning, and thereby provides a new avenue for the rehabilitation of learning disorders.

Vowel content influences relative pitch perception in vocal melodies: A comparison of models based on brightness vs. intrinsic pitch of vowels

Past research involving real and synthesized instrumental timbres has found that note-to-note changes in brightness can influence perception of interval size. Changes that are congruent with changes in pitch led to an expansion, whereas changes that are incongruent lead to a contraction. In the case of singing, the brightness of individual notes (as measured by the spectral centroid) will vary as a function of vowel content. In a recent study, we investigated whether note-to-note changes in the brightness of sung notes were capable of influencing the perception of interval size. While results were consistent with past work on instrumental timbres, we were not able to completely rule out an alternative explanation concerning a perceptual correction for the intrinsic pitch of vowels (e.g., f0 of /i/ tends to be produced higher than /a/). In the present study, we created 288 unique note pairs that varied with regard to absolute change in f0 as well as vowel content. Vowels were sampled from across the vowel space, which allowed us to generate unique predictors for change in brightness (spectral centroid) and changes in intrinsic pitch (F2). Regression analyses will compare the effectiveness of competing models.Past research involving real and synthesized instrumental timbres has found that note-to-note changes in brightness can influence perception of interval size. Changes that are congruent with changes in pitch led to an expansion, whereas changes that are incongruent lead to a contraction. In the case of singing, the brightness of individual notes (as measured by the spectral centroid) will vary as a function of vowel content. In a recent study, we investigated whether note-to-note changes in the brightness of sung notes were capable of influencing the perception of interval size. While results were consistent with past work on instrumental timbres, we were not able to completely rule out an alternative explanation concerning a perceptual correction for the intrinsic pitch of vowels (e.g., f0 of /i/ tends to be produced higher than /a/). In the present study, we created 288 unique note pairs that varied with regard to absolute change in f0 as well as vowel content. Vowels were sampled from across the vowel ...