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Brain imaging studies have reported that the neural deficits of congenital amusia in non‐tonal language speakers are mainly in the connectivity between the auditory cortex and the inferior frontal gyrus (IFG) in the right hemisphere. However, the relationship between the functional connectivity (FC) in these regions and the music perception ability of amusia in tonal language speakers remains unclear. In this study, we investigated the FC characteristics of amusia in Mandarin speakers in resting‐state functional magnetic resonance imaging data by voxel‐wise connectivity analyses with seeds in left and right Heschl's gyri (HG) and region of interest (ROI)‐to‐ROI connectivity analyses. Our findings indicate increased connectivity between right HG and bilateral posterior superior temporal gyrus, as determined by voxel‐wise connectivity analyses in amusia. Conversely, reduced connectivity was observed between bilateral HG and bilateral IFG (orbital part) as assessed through ROI‐to‐ROI connectivity analyses in amusia when compared to controls. Moreover, the music perception scores of amusia in Mandarin speakers were associated with diminished connectivity between the left HG and the right IFG. This study furnishes direct evidence for the link between music perception deficits and the aberrant frontotemporal connectivity of congenital amusia in tonal language speakers in resting state. [ABSTRACT FROM AUTHOR]

The present longitudinal study investigated the hypothesis that early musical skills (as measured by melodic and rhythmic perception and memory) predict later literacy development via a mediating effect of phonology. We examined 130 French‐speaking children, 31 of whom with a familial risk for developmental dyslexia (DD). Their abilities in the three domains were assessed longitudinally with a comprehensive battery of behavioral tests in kindergarten, first grade, and second grade. Using a structural equation modeling approach, we examined potential longitudinal effects from music to literacy via phonology. We then investigated how familial risk for DD may influence these relationships by testing whether atypical music processing is a risk factor for DD. Results showed that children with a familial risk for DD consistently underperformed children without familial risk in music, phonology, and literacy. A small effect of musical ability on literacy via phonology was observed, but may have been induced by differences in stability across domains over time. Furthermore, early musical skills did not add significant predictive power to later literacy difficulties beyond phonological skills and family risk status. These findings are consistent with the idea that certain key auditory skills are shared between music and speech processing, and between DD and congenital amusia. However, they do not support the notion that music perception and memory skills can serve as a reliable early marker of DD, nor as a valuable target for reading remediation. Research Highlights: Music, phonology, and literacy skills of 130 children, 31 of whom with a familial risk for dyslexia, were examined longitudinally.Children with a familial risk for dyslexia consistently underperformed children without familial risk in musical, phonological, and literacy skills.Structural equation models showed a small effect of musical ability in kindergarten on literacy in second grade, via phonology in first grade.However, early musical skills did not add significant predictive power to later literacy difficulties beyond phonological skills and family risk status. [ABSTRACT FROM AUTHOR]

Perceiving pitch is a central function of the human auditory system; congenital amusia is a disorder of pitch perception. The underlying neural mechanisms of congenital amusia have been actively discussed. However, little attention has been paid to the changes in the motor rain within congenital amusia. In this case-control study, 17 participants with congenital amusia and 14 healthy controls underwent functional magnetic resonance imaging while resting with their eyes closed. A voxel-based degree centrality method was used to identify abnormal functional network centrality by comparing degree centrality values between the congenital amusia group and the healthy control group. We found decreased degree centrality values in the right primary sensorimotor areas in participants with congenital amusia relative to controls, indicating potentially decreased centrality of the corresponding brain regions in the auditory-sensory motor feedback network. We found a significant positive correlation between the degree centrality values and the Montreal Battery of Evaluation of Amusia scores. In conclusion, our study identified novel, hitherto undiscussed candidate brain regions that may partly contribute to or be modulated by congenital amusia. Our evidence supports the view that sensorimotor coupling plays an important role in memory and musical discrimination. The study was approved by the Ethics Committee of the Second Xiangya Hospital, Central South University, China (No. WDX20180101GZ01) on February 9, 2019.

Processing auditory sequences involves multiple brain networks and is crucial to complex perception associated with music appreciation and speech comprehension. We used time-resolved cortical imaging in a pitch change detection task to detail the underlying nature of human brain network activity, at the rapid time scales of neurophysiology. In response to tone sequence presentation to the participants, we observed slow inter-regional signaling at the pace of tone presentations (2-4Hz) that was directed from auditory cortex toward both inferior frontal and motor cortices. Symmetrically, motor cortex manifested directed influence onto auditory and inferior frontal cortices via bursts of faster (15-35 Hz) activity. These bursts occurred precisely at the expected latencies of each tone in a sequence. This expression of interdependency between slow/fast neurophysiological activity yielded a form of local cross-frequency phase-amplitude coupling in auditory cortex, which strength varied dynamically and peaked when pitch changes were anticipated. We clarified the mechanistic relevance of these observations in relation to behavior by including a group of individuals afflicted by congenital amusia, as a model of altered function in processing sound sequences. In amusia, we found a depression of inter-regional slow signaling toward motor and inferior frontal cortices, and a chronic overexpression of slow/fast phase-amplitude coupling in auditory cortex. These observations are compatible with a misalignment between the respective neurophysiological mechanisms of stimulus encoding and internal predictive signaling, which was absent in controls. In summary, our study provides a functional and mechanistic account of neurophysiological activity for predictive, sequential timing of auditory inputs. [ABSTRACT FROM AUTHOR]

CONGENITAL AMUSIA IS A NEUROGENETIC DISORDER of pitch perception that may also compromise pitch production. Despite amusics' long documented difficulties with pitch, previous evidence suggests that familiar music may have an implicit facilitative effect on their performance. It remains, however, unknown whether vocal imitation of song in amusia is influenced by melody familiarity and the presence of lyrics. To address this issue, thirteen Mandarin speaking amusics and 13 matched controls imitated novel song segments with lyrics and on the syllable/la/. Eleven out of these participants in each group also imitated segments of a familiar song. Subsequent acoustic analysis was conducted to measure pitch and timing matching accuracy based on eight acoustic measures. While amusics showed worse imitation performance than controls across seven out of the eight pitch and timing measures, melody familiarity was found to have a favorable effect on their performance on three pitch-related acoustic measures. The presence of lyrics did not affect either group's performance substantially. Correlations were observed between amusics' performance on the Montreal Battery of Evaluation of Amusia and imitation of the novel song. We discuss implications in terms of music familiarity, memory demands, the relevance of lexical information, and the link between perception and production. [ABSTRACT FROM AUTHOR]

Background: Congenital amusia (CA) is a rare disorder characterized by deficits in pitch perception, and many structural and functional magnetic resonance imaging studies have been conducted to better understand its neural bases. However, a structural magnetic resonance imaging analysis using a surface-based morphology method to identify regions with cortical features abnormalities at the vertex-based level has not yet been performed.Methods: Fifteen participants with CA and 13 healthy controls underwent structural magnetic resonance imaging. A surface-based morphology method was used to identify anatomical abnormalities. Then, the surface parameters' mean value of the identified clusters with statistically significant between-group differences were extracted and compared. Finally, Pearson's correlation analysis was used to assess the correlation between the Montreal Battery of Evaluation of Amusia (MBEA) scores and surface parameters.Results: The CA group had significantly lower MBEA scores than the healthy controls (p = 0.000). The CA group exhibited a significant higher fractal dimension in the right caudal middle frontal gyrus and a lower sulcal depth in the right pars triangularis gyrus (p < 0.05; false discovery rate-corrected at the cluster level) compared to healthy controls. There were negative correlations between the mean fractal dimension values in the right caudal middle frontal gyrus and MBEA score, including the mean MBEA score (r = −0.5398, p = 0.0030), scale score (r = −0.5712, p = 0.0015), contour score (r = −0.4662, p = 0.0124), interval score (r = −0.4564, p = 0.0146), rhythmic score (r = −0.5133, p = 0.0052), meter score (r = −0.3937, p = 0.0382), and memory score (r = −0.3879, p = 0.0414). There was a significant positive correlation between the mean sulcal depth in the right pars triangularis gyrus and the MBEA score, including the mean score (r = 0.5130, p = 0.0052), scale score (r = 0.5328, p = 0.0035), interval score (r = 0.4059, p = 0.0321), rhythmic score (r = 0.5733, p = 0.0014), meter score (r = 0.5061, p = 0.0060), and memory score (r = 0.4001, p = 0.0349).Conclusion: Individuals with CA exhibit cortical morphological changes in the right hemisphere. These findings may indicate that the neural basis of speech perception and memory impairments in individuals with CA is associated with abnormalities in the right pars triangularis gyrus and middle frontal gyrus, and that these cortical abnormalities may be a neural marker of CA.

Amusia also known as tone deafness affects roughly 1.5% population. Congenital amusia appears from birth and lasts over life span. Usually, it is not associated with other diseases. Its link to hearing impairment has been definitively excluded. Neurobiological studies point to asymmetrical processing of musical signals in auditory cortex of left and right brain hemispheres. The finding was supported by discovering microlesions in the right-side gray matter. Because of its connection with asymmetry, amusia has been classified to disconnection syndromes. Alternatively to the neurobiological explanation of amusia background, an attention was turned to the significance of genetic factors. The studies done on relatives and twins indicated familial aggregation of amusia. Molecular genetic investigations linked amusia with deletion of 22q11.2 chromosome region. Until now no specific genes responsible for development of amusia were found. [ABSTRACT FROM AUTHOR]

Interhemispheric connectivity of the two cerebral hemispheres is crucial for a broad repertoire of cognitive functions including music and language. Congenital amusia has been reported as a neurodevelopment disorder characterized by impaired music perception and production. However, little is known about the characteristics of the interhemispheric functional connectivity (FC) in amusia. In the present study, we used a newly developed voxel-mirrored homotopic connectivity (VMHC) method to investigate the interhemispheric FC of the whole brain in amusia at resting-state. Thirty amusics and 29 matched participants underwent a resting-state functional magnetic resonance imaging (fMRI) scanning. An automated VMHC approach was used to analyze the fMRI data. Compared to the control group, amusics showed increased VMHC within the posterior part of the default mode network (DMN) mainly in the posterior superior temporal gyrus (pSTG) and posterior cingulate cortex (PCC). Correlation analyses revealed negative correlations between the VMHC value in pSTG/PCC and the music perception ability among amusics. Further ROC analyses showed that the VMHC value of pSTG/PCC showed a good sensibility/specificity to differentiate the amusics from the controls. These findings provide a new perspective for understanding the neural basis of congenital amusia and imply the immature state of DMN may be a credible neural marker of amusia.

Interhemispheric connectivity of the two cerebral hemispheres is crucial for a broad repertoire of cognitive functions including music and language. Congenital amusia has been reported as a neurodevelopment disorder characterized by impaired music perception and production. However, little is known about the characteristics of the interhemispheric functional connectivity (FC) in amusia. In the present study, we used a newly developed voxel-mirrored homotopic connectivity (VMHC) method to investigate the interhemispheric FC of the whole brain in amusia at resting-state. Thirty amusics and 29 matched participants underwent a resting-state functional magnetic resonance imaging (fMRI) scanning. An automated VMHC approach was used to analyze the fMRI data. Compared to the control group, amusics showed increased VMHC within the posterior part of the default mode network (DMN) mainly in the posterior superior temporal gyrus (pSTG) and posterior cingulate cortex (PCC). Correlation analyses revealed negative correlations between the VMHC value in pSTG/PCC and the music perception ability among amusics. Further ROC analyses showed that the VMHC value of pSTG/PCC showed a good sensibility/specificity to differentiate the amusics from the controls. These findings provide a new perspective for understanding the neural basis of congenital amusia and imply the immature state of DMN may be a credible neural marker of amusia. [ABSTRACT FROM AUTHOR]

Congenital amusia in its most common form is a disorder characterized by a musical pitch processing deficit. Although pitch is involved in conveying emotion in music, the implications for pitch deficits on musical emotion judgements is still under debate. Relatedly, both limited and spared musical emotion recognition was reported in amusia in conditions where emotion cues were not determined by musical mode or dissonance. Additionally, assumed links between musical abilities and visuo-spatial attention processes need further investigation in congenital amusics. Hence, we here test to what extent musical emotions can influence attentional performance. Fifteen congenital amusic adults and fifteen healthy controls matched for age and education were assessed in three attentional conditions: executive control (distractor inhibition), alerting, and orienting (spatial shift) while music expressing either joy, tenderness, sadness, or tension was presented. Visual target detection was in the normal range for both accuracy and response times in the amusic relative to the control participants. Moreover, in both groups, music exposure produced facilitating effects on selective attention that appeared to be driven by the arousal dimension of musical emotional content, with faster correct target detection during joyful compared to sad music. These findings corroborate the idea that pitch processing deficits related to congenital amusia do not impede other cognitive domains, particularly visual attention. Furthermore, our study uncovers an intact influence of music and its emotional content on the attentional abilities of amusic individuals. The results highlight the domain-selectivity of the pitch disorder in congenital amusia, which largely spares the development of visual attention and affective systems.

Congenital amusia is an inborn neurogenetic disorder of musical pitch processing, which also induces impairment in lexical tone perception. However, it has not been examined before how the brain specialization of lexical tone perception is affected in amusics. The current study adopted the dichotic listening paradigm to examine this issue, testing 18 Cantonese-speaking amusics and 18 matched controls on pitch/lexical tone identification and discrimination in three conditions: non-speech tone, low syllable variation, and high syllable variation. For typical listeners, the discrimination accuracy was higher with shorter RT in the left ear regardless of the stimulus types, suggesting a left-ear advantage in discrimination. When the demand of phonological processing increased, as in the identification task, shorter RT was still obtained in the left ear, however, the identification accuracy revealed a bilateral pattern. Taken together, the results of the identification task revealed a reduced LEA or a shift from the right hemisphere to bilateral processing in identification. Amusics exhibited overall poorer performance in both identification and discrimination tasks, indicating that pitch/lexical tone processing in dichotic listening settings was impaired, but there was no evidence that amusics showed different ear preference from controls. These findings provided temporary evidence that although amusics demonstrate deficient neural mechanisms of pitch/lexical tone processing, their ear preference patterns might not be affected. These results broadened the understanding of the nature of pitch and lexical tone processing deficiencies in amusia.

Congenital amusia is a lifelong impairment in musical ability. Individuals with amusia are found to show reduced sensitivity to emotion recognition in speech prosody and silent facial expressions, implying a possible cross-modal emotion-processing deficit. However, it is not clear whether the observed deficits are primarily confined to socio-emotional contexts, where visual cues (facial expression) often co-occur with auditory cues (emotion prosody) to express intended emotions, or extend to linguistic emotion processing. In order to better understand the underlying deficiency mechanism of emotion processing in individuals with amusia, we examined whether reduced sensitivity to emotional processing extends to the recognition of emotion category and valence of written words in individuals with amusia. Twenty Cantonese speakers with amusia and 17 controls were tested in three experiments: (1) emotion prosody rating, in which participants rated how much each spoken sentence was expressed in each of the four emotions on 7-point rating scales; (2) written word emotion recognition, in which participants recognized the emotion of written emotion words; and (3) written word valence judgment, in which participants judged the valence of written words. Results showed that participants with amusia preformed significantly less accurately than controls in emotion prosody recognition; in contrast, the two groups showed no significant difference in accuracy rates in both written word tasks (emotion recognition and valence judgment). The results indicate that the impairment of individuals with amusia in emotion processing may not generalize to linguistic emotion processing in written words, implying that the emotion deficit is likely to be restricted to socio-emotional contexts in individuals with amusia. [ABSTRACT FROM AUTHOR]

Congenital amusia in its most common form is a disorder characterized by a musical pitch processing deficit. Although pitch is involved in conveying emotion in music, the implications for pitch deficits on musical emotion judgements is still under debate. Relatedly, both limited and spared musical emotion recognition was reported in amusia in conditions where emotion cues were not determined by musical mode or dissonance. Additionally, assumed links between musical abilities and visuo-spatial attention processes need further investigation in congenital amusics. Hence, we here test to what extent musical emotions can influence attentional performance. Fifteen congenital amusic adults and fifteen healthy controls matched for age and education were assessed in three attentional conditions: executive control (distractor inhibition), alerting, and orienting (spatial shift) while music expressing either joy, tenderness, sadness, or tension was presented. Visual target detection was in the normal range for both accuracy and response times in the amusic relative to the control participants. Moreover, in both groups, music exposure produced facilitating effects on selective attention that appeared to be driven by the arousal dimension of musical emotional content, with faster correct target detection during joyful compared to sad music. These findings corroborate the idea that pitch processing deficits related to congenital amusia do not impede other cognitive domains, particularly visual attention. Furthermore, our study uncovers an intact influence of music and its emotional content on the attentional abilities of amusic individuals. The results highlight the domain-selectivity of the pitch disorder in congenital amusia, which largely spares the development of visual attention and affective systems. [ABSTRACT FROM AUTHOR]

Congenital amusia is an inborn neurogenetic disorder of musical pitch processing, which also induces impairment in lexical tone perception. However, it has not been examined before how the brain specialization of lexical tone perception is affected in amusics. The current study adopted the dichotic listening paradigm to examine this issue, testing 18 Cantonese-speaking amusics and 18 matched controls on pitch/lexical tone identification and discrimination in three conditions: non-speech tone, low syllable variation, and high syllable variation. For typical listeners, the discrimination accuracy was higher with shorter RT in the left ear regardless of the stimulus types, suggesting a left-ear advantage in discrimination. When the demand of phonological processing increased, as in the identification task, shorter RT was still obtained in the left ear, however, the identification accuracy revealed a bilateral pattern. Taken together, the results of the identification task revealed a reduced LEA or a shift from the right hemisphere to bilateral processing in identification. Amusics exhibited overall poorer performance in both identification and discrimination tasks, indicating that pitch/lexical tone processing in dichotic listening settings was impaired, but there was no evidence that amusics showed different ear preference from controls. These findings provided temporary evidence that although amusics demonstrate deficient neural mechanisms of pitch/lexical tone processing, their ear preference patterns might not be affected. These results broadened the understanding of the nature of pitch and lexical tone processing deficiencies in amusia. [ABSTRACT FROM AUTHOR]

In this article, we report the first documented case of congenital amusia in dizygotic twins. The female twin pair was 27 years old at the time of testing, with normal hearing and above average intelligence. Both had formal music lesson from the age of 8–12 and were exposed to music in their childhood. Using the Montreal Battery of Evaluation of Amusia (Peretz et al., 2003), one twin was diagnosed as amusic, with a pitch perception as well as a rhythm perception deficit, while the other twin had normal pitch and rhythm perception. We conducted a large battery of tests assessing the performance of the twins in music, pitch perception and memory, language perception and spatial processing. Both showed an identical albeit low pitch memory span of 3.5 tones and an impaired performance on a beat alignment task, yet the non-amusic twin outperformed the amusic twin in three other musical and all language related tasks. The twins also differed significantly in their performance on one of two spatial tasks (visualization), with the non-amusic twin outperforming the amusic twin (83% vs. 20% correct). The performance of the twins is also compared to normative samples of normal and amusic participants from other studies. This twin case study highlights that congenital amusia is not due to insufficient exposure to music in childhood: The exposure to music of the twin pair was as comparable as it can be for two individuals. This study also indicates that there is an association between amusia and a spatial processing deficit (see Douglas and Bilkey, 2007; contra Tillmann et al., 2010; Williamson et al., 2011) and that more research is needed in this area.

This study investigated whether there is a co-occurrence between developmental dyslexia and congenital amusia in adults. First, a database of online musical tests on 18,000 participants was analysed. Self-reported dyslexic participants performed significantly lower on melodic skills than matched controls, suggesting a possible link between reading and musical disorders. In order to test this relationship more directly, we evaluated 20 participants diagnosed with dyslexia, 16 participants diagnosed with amusia, and their matched controls, with a whole battery of literacy (reading, fluency, spelling), phonological (verbal working memory, phonological awareness) and musical tests (melody, rhythm and metre perception, incidental memory). Amusia was diagnosed in six (30%) dyslexic participants and reading difficulties were found in four (25%) amusic participants. Thus, the results point to a moderate comorbidity between amusia and dyslexia. Further research will be needed to determine what factors at the neural and/or cognitive levels are responsible for this co-occurrence. [ABSTRACT FROM AUTHOR]

Highlights • The neural basis of imitation-induced musical meaning processing remains unclear. • A cross-modal semantic priming paradigm was used in this fMRI study. • Participants judged whether the meaning of the prime-target pair was congruent. • Controls but not amusics showed greater activations of left parietofrontal areas. • The human mirror system refers to understanding imitation-induced musical meaning. Abstract Music can convey meanings by imitating phenomena of the extramusical world, and these imitation-induced musical meanings can be understood by listeners. Although the human mirror system (HMS) is implicated in imitation, little is known about the HMS's role in making sense of meaning that derives from musical imitation. To answer this question, we used fMRI to examine listeners' brain activities during the processing of imitation-induced musical meaning with a cross-modal semantic priming paradigm. Eleven normal individuals and 11 individuals with congenital amusia, a neurodevelopmental disorder of musical processing, participated in the experiment. Target pictures with either an upward or downward movement were primed by semantically congruent or incongruent melodic sequences characterized by the direction of pitch change (upward or downward). When contrasting the incongruent with the congruent condition between the two groups, we found greater activations in the left supramarginal gyrus/inferior parietal lobule and inferior frontal gyrus in normals but not in amusics. The implications of these findings in terms of the role of the HMS in understanding imitation-induced musical meaning are discussed. [ABSTRACT FROM AUTHOR]

Abstract: Auditory short‐term memory (STM) is a fundamental ability to make sense of auditory information as it unfolds over time. Whether separate STM systems exist for different types of auditory information (music and speech, in particular) is a matter of debate. The present paper reviews studies that have investigated both musical and verbal STM in healthy individuals and in participants with neurodevelopmental and neurological disorders. Overall, the results are in favor of only partly shared networks for musical and verbal STM. Evidence for a distinction in STM for the two materials stems from (1) behavioral studies in healthy participants, in particular from the comparison between nonmusicians and musicians; (2) behavioral studies in congenital amusia, where a selective pitch STM deficit is observed; and (3) studies in brain‐damaged patients with cases of double dissociation. In this review we highlight the need for future studies comparing STM for the same perceptual dimension (e.g., pitch) in different materials (e.g., music and speech), as well as for studies aiming at a more insightful characterization of shared and distinct mechanisms for speech and music in the different components of STM, namely encoding, retention, and retrieval. [ABSTRACT FROM AUTHOR]

In this article, we report the first documented case of congenital amusia in dizygotic twins. The female twin pair was 27 years old at the time of testing, with normal hearing and above average intelligence. Both had formal music lesson from the age of 8–12 and were exposed to music in their childhood. Using the Montreal Battery of Evaluation of Amusia (Peretz et al., 2003 ), one twin was diagnosed as amusic, with a pitch perception as well as a rhythm perception deficit, while the other twin had normal pitch and rhythm perception. We conducted a large battery of tests assessing the performance of the twins in music, pitch perception and memory, language perception and spatial processing. Both showed an identical albeit low pitch memory span of 3.5 tones and an impaired performance on a beat alignment task, yet the non-amusic twin outperformed the amusic twin in three other musical and all language related tasks. The twins also differed significantly in their performance on one of two spatial tasks (visualization), with the non-amusic twin outperforming the amusic twin (83% vs. 20% correct). The performance of the twins is also compared to normative samples of normal and amusic participants from other studies. This twin case study highlights that congenital amusia is not due to insufficient exposure to music in childhood: The exposure to music of the twin pair was as comparable as it can be for two individuals. This study also indicates that there is an association between amusia and a spatial processing deficit (see Douglas and Bilkey, 2007 ; contra Tillmann et al., 2010 ; Williamson et al., 2011 ) and that more research is needed in this area. [ABSTRACT FROM AUTHOR]

Music and language are two intricately linked communication modalities in humans. A deficit in music pitch processing as manifested in the condition of congenital amusia has been related to difficulties in lexical tone processing for both tone and non-tonal languages. However, it is still unclear whether amusia also affects the perception of vowel phonemes in quiet and in noise. In this study, we examined vowel-plus-tone identification in quiet and noise conditions among Mandarin-speaking amusics with and without speech tone difficulties (tone agnosics and pure amusics, respectively), and IQ- and age-matched controls. Overall, pure amusics showed vowel and tone identification comparable to the controls in both quiet and noise conditions. Compared to pure amusics and controls, tone agnosics showed deficits in tone perception in both quiet and noise conditions. More importantly, their vowel perception was lower than pure amusics and controls in noise conditions, e.g., at a signal-to-noise ratio of −4 dB, although they showed normal-like performance in quiet and at a signal-to-noise ratio of −8 dB. These results suggest that when amusia affected speech tone processing (e.g., tone agnosics), it could also compromise vowel processing in noise. However, amusia alone does not affect tone or vowel perception in Mandarin Chinese either in quiet or in noise. Overall, the current study highlights the necessity of taking heterogeneity within the amusic group into account when considering the related speech deficits in this group. [ABSTRACT FROM AUTHOR]

The arcuate fasciculus (AF) is a neural fiber tract that is critical to speech and music development. Although the predominant role of the left AF in speech development is relatively clear, how the AF engages in music development is not understood. Congenital amusia is a special neurodevelopmental condition, which not only affects musical pitch but also speech tone processing. Using diffusion tensor tractography, we aimed at understanding the role of AF in music and speech processing by examining the neural connectivity characteristics of the bilateral AF among thirty Mandarin amusics. Compared to age- and intelligence quotient (IQ)-matched controls, amusics demonstrated increased connectivity as reflected by the increased fractional anisotropy in the right posterior AF but decreased connectivity as reflected by the decreased volume in the right anterior AF. Moreover, greater fractional anisotropy in the left direct AF was correlated with worse performance in speech tone perception among amusics. This study is the first to examine the neural connectivity of AF in the neurodevelopmental condition of amusia as a result of disrupted music pitch and speech tone processing. We found abnormal white matter structural connectivity in the right AF for the amusic individuals. Moreover, we demonstrated that the white matter microstructural properties of the left direct AF is modulated by lexical tone deficits among the amusic individuals. These data support the notion of distinctive pitch processing systems between music and speech. [ABSTRACT FROM AUTHOR]

Previous studies on congenital amusia mainly focused on the impaired fronto-temporal pathway. It is possible that neural pathways of amusia patients on a larger scale are affected. In this study, we investigated changes in structural connections by applying both tract-based and network-based analysis to DTI data of 12 subjects with congenital amusia and 20 demographic-matched normal controls. TBSS (tract-based spatial statistics) was used to detect microstructural changes. The results showed that amusics had higher diffusivity indices in the corpus callosum, the right inferior/superior longitudinal fasciculus, and the right inferior frontal-occipital fasciculus (IFOF). The axial diffusivity values of the right IFOF were negatively correlated with musical scores in the amusia group. Network-based analysis showed that the efficiency of the brain network was reduced in amusics. The impairments of WM tracts were also found to be correlated with reduced network efficiency in amusics. This suggests that impaired WM tracts may lead to the reduced network efficiency seen in amusics. Our findings suggest that congenital amusia is a disconnection syndrome.

Congenital amusia is a neurodevelopmental disorder, characterized by a difficulty detecting pitch deviation that is related to abnormal electrical brain responses. Abnormalities found along the right fronto-temporal pathway between the inferior frontal gyrus (IFG) and the auditory cortex (AC) are the likely neural mechanism responsible for amusia. To investigate the causal role of these regions during the detection of pitch deviants, we applied cathodal (inhibitory) transcranial direct current stimulation (tDCS) over right frontal and right temporal regions during separate testing sessions. We recorded participants’ electrical brain activity (EEG) before and after tDCS stimulation while they performed a pitch change detection task. Relative to a sham condition, there was a decrease in P3 amplitude after cathodal stimulation over both frontal and temporal regions compared to pre-stimulation baseline. This decrease was associated with small pitch deviations (6.25 cents), but not large pitch deviations (200 cents). Overall, this demonstrates that using tDCS to disrupt regions around the IFG and AC can induce temporary changes in evoked brain activity when processing pitch deviants. These electrophysiological changes are similar to those observed in amusia and provide causal support for the connection between P3 and fronto-temporal brain regions. [ABSTRACT FROM AUTHOR]

Spatial representation of pitch plays a central role in auditory processing. However, it is unknown whether impaired auditory processing is associated with impaired pitch–space mapping. Experiment 1 examined spatial representation of pitch in individuals with congenital amusia using a stimulus–response compatibility (SRC) task. For amusic and non-amusic participants, pitch classification was faster and more accurate when correct responses involved a physical action that was spatially congruent with the pitch height of the stimulus than when it was incongruent. However, this spatial representation of pitch was not as stable in amusic individuals, revealed by slower response times when compared with control individuals. One explanation is that the SRC effect in amusics reflects a linguistic association, requiring additional time to link pitch height and spatial location. To test this possibility, Experiment 2 employed a colour-classification task. Participants judged colour while ignoring a concurrent pitch by pressing one of two response keys positioned vertically to be congruent or incongruent with the pitch. The association between pitch and space was found in both groups, with comparable response times in the two groups, suggesting that amusic individuals are only slower to respond to tasks involving explicit judgments of pitch. [ABSTRACT FROM PUBLISHER]

We present a follow-up study on the case of a Greek amusic adult, B.Z., whose impaired performance on scale, contour, interval, and meter was reported by Paraskevopoulos, Tsapkini, and Peretz in 2010, employing a culturally-tailored version of the Montreal Battery of Evaluation of Amusia. In the present study, we administered a novel set of perceptual judgement tasks designed to investigate the ability to appreciate holistic prosodic aspects of 'expressiveness' and emotion in phrase length music and speech stimuli. Our results show that, although diagnosed as a congenital amusic, B.Z. scored as well as healthy controls (N=24) on judging 'expressiveness' and emotional prosody in both speech and music stimuli. These findings suggest that the ability to make perceptual judgements about such prosodic qualities may be preserved in individuals who demonstrate difficulties perceiving basic musical features such as melody or rhythm. B.Z.'s case yields new insights into amusia and the processing of speech and music prosody through a holistic approach. The employment of novel stimuli with relatively fewer non-naturalistic manipulations, as developed for this study, may be a useful tool for revealing unexplored aspects of music and speech cognition and offer the possibility to further the investigation of the perception of acoustic streams in more authentic auditory conditions. [ABSTRACT FROM AUTHOR]

Congenital amusia is a lifelong neurodevelopmental disorder of fine-grained pitch processing. In this fMRI study, we examined the neural bases of congenial amusia in speakers of a tonal language – Cantonese. Previous studies on non-tonal language speakers suggest that the neural deficits of congenital amusia lie in the music-selective neural circuitry in the right inferior frontal gyrus (IFG). However, it is unclear whether this finding can generalize to congenital amusics in tonal languages. Tonal language experience has been reported to shape the neural processing of pitch, which raises the question of how tonal language experience affects the neural bases of congenital amusia. To investigate this question, we examined the neural circuitries sub-serving the processing of relative pitch interval in pitch-matched Cantonese level tone and musical stimuli in 11 Cantonese-speaking amusics and 11 musically intact controls. Cantonese-speaking amusics exhibited abnormal brain activities in a widely distributed neural network during the processing of lexical tone and musical stimuli. Whereas the controls exhibited significant activation in the right superior temporal gyrus (STG) in the lexical tone condition and in the cerebellum regardless of the lexical tone and music conditions, no activation was found in the amusics in those regions, which likely reflects a dysfunctional neural mechanism of relative pitch processing in the amusics. Furthermore, the amusics showed abnormally strong activation of the right middle frontal gyrus and precuneus when the pitch stimuli were repeated, which presumably reflect deficits of attending to repeated pitch stimuli or encoding them into working memory. No significant group difference was found in the right IFG in either the whole-brain analysis or region-of-interest analysis. These findings imply that the neural deficits in tonal language speakers might differ from those in non-tonal language speakers, and overlap partly with the neural circuitries of lexical tone processing (e.g. right STG). [ABSTRACT FROM AUTHOR]

Beat deafness, a recently documented form of congenital amusia, provides a unique window into functional specialization of neural circuitry for the processing of musical stimuli: Beat-deaf individuals exhibit deficits that are specific to the detection of a regular beat in music and the ability to move along with a beat. Studies on the neural underpinnings of beat processing in the general population suggest that the auditory system is capable of pre-attentively generating a predictive model of upcoming sounds in a rhythmic pattern, subserved largely within auditory cortex and reflected in mismatch negativity (MMN) and P3 event-related potential (ERP) components. The current study examined these neural correlates of beat perception in two beat-deaf individuals, Mathieu and Marjorie, and a group of control participants under conditions in which auditory stimuli were either attended or ignored. Compared to control participants, Mathieu demonstrated reduced behavioral sensitivity to beat omissions in metrical patterns, and Marjorie showed a bias to identify irregular patterns as regular. ERP responses to beat omissions reveal an intact pre-attentive system for processing beat irregularities in cases of beat deafness, reflected in the MMN component, and provide partial support for abnormalities in later cognitive stages of beat processing, reflected in an unreliable P3b component exhibited by Mathieu – but not Marjorie – compared to control participants. P3 abnormalities observed in the current study resemble P3 abnormalities exhibited by individuals with pitch-based amusia, and are consistent with attention or auditory-motor coupling accounts of deficits in beat perception.

Congenital amusia is a neurodevelopmental disorder of musical processing. Previous research demonstrates that although explicit musical processing is impaired in congenital amusia, implicit musical processing can be intact. However, little is known about whether implicit knowledge could improve explicit musical processing in individuals with congenital amusia. To this end, we developed a training method utilizing redescription-associate learning, aiming at transferring implicit representations of perceptual states into explicit forms through verbal description and then establishing the associations between the perceptual states reported and responses via feedback, to investigate whether the explicit processing of melodic structure could be improved in individuals with congenital amusia. Sixteen amusics and 11 controls rated the degree of expectedness of melodies during EEG recording before and after training. In the interim, half of the amusics received nine training sessions on melodic structure, while the other half received no training. Results, based on effect size estimation, showed that at pretest, amusics but not controls failed to explicitly distinguish the regular from the irregular melodies and to exhibit an ERAN in response to the irregular endings. At posttest, trained but not untrained amusics performed as well as controls at both the behavioral and neural levels. At the 3-month follow-up, the training effects still maintained. These findings present novel electrophysiological evidence of neural plasticity in the amusic brain, suggesting that redescription-associate learning may be an effective method to remediate impaired explicit processes for individuals with other neurodevelopmental disorders who have intact implicit knowledge. • Amusia is characterized by intact implicit and impaired explicit pitch perception. • We developed a redescription-associate learning method to treat amusics' deficits. • Prior to training, amusics failed to explicitly process melodic structure. • After training, amusics showed normal performance at behavioral and neural levels. • Training effects on melodic processing in amusia maintained at 3-month follow-up. [ABSTRACT FROM AUTHOR]

Previous research suggests that within Mandarin-speaking congenital amusics, only a subgroup has behavioral lexical tone perception impairments (tone agnosia), whereas the rest of amusics do not. The purpose of the current study was to investigate the categorical nature of lexical tone perception in Mandarin-speaking amusics with and without behavioral lexical tone deficits. Three groups of listeners (controls, pure amusics and amusics with tone agnosia) participated in tone identification and discrimination tasks. Indexes of the categorical perception of a physical continuum of fundamental frequencies ranging from a rising to level tone were measured. Specifically, the stimulus durations were manipulated at 100 and 200 ms. For both stimulus durations, all groups exhibited similar categorical boundaries. The pure amusics showed sharp identification slopes and significantly peaked discrimination functions similar to those of normal controls. However, such essential characteristics for the categorical perception of lexical tones were not observed in amusics with tone agnosia. An enlarged step-size from 20 Hz to 35 Hz was not able to produce any discrimination peaks in tone agnosics either. The current study revealed that only amusics with tone agnosia showed a lack of categorical tone perception, while the pure amusics demonstrated typical categorical perception of lexical tones, indicating that the deficit of pitch processing in music does not necessarily result in the deficit in the categorical perception of lexical tones. The different performance between congenital amusics with and without tone agnosia provides a new perspective on the proposition of the relationship between music and speech perception.

This article presents a critical survey of the prevalent usage of the Montreal Battery of Evaluation of Amusia (MBEA; Peretz et al., 2003) to assess congenital amusia, a neuro-developmental disorder that has been claimed to be present in 4% of the population (Kalmus and Fry, 1980). It reviews and discusses the current usage of the MBEA in relation to cut-off scores, number of used subtests, manner of testing, and employed statistics, as these vary in the literature. Furthermore, data are presented from a large-scale experiment with 228 German undergraduate students who were assessed with the MBEA and a comprehensive questionnaire. This experiment tested the difference between scores that were obtained in a web-based study (at participants’ homes) and those obtained under laboratory conditions with a computerized version of the MBEA. In addition to traditional statistical procedures, the data were evaluated using Signal Detection Theory (SDT; Green and Swets, 1966), taking into consideration the individual’s ability to discriminate and their response bias. Results show that using SDT for scoring instead of proportion correct offers a bias-free and normally distributed measure of discrimination ability. In addition it is also demonstrated that a diagnosis based on an average score leads to cases of misdiagnosis. The prevalence of congenital amusia is shown to depend highly on the statistical criterion that is applied as cut-off score and on the number of subtests that is considered for the diagnosis. In addition, three different subtypes of amusics were found in our sample. Lastly, significant differences between the web-based and the laboratory group were found, giving rise to questions about the validity of web-based experimentation.

Background: Amusia is a disorder that is known to affect the processing of musical pitch. Although individuals with amusia rarely show language deficits in daily life, a number of findings point to possible impairments in speech prosody that amusic perceivers may compensate for by drawing on linguistic information. Using EEG, we investigated (1) whether the processing of speech prosody is impaired in amusia and (2) whether emotional linguistic information can ease this process. Method: Twenty Chinese amusics and 22 matched controls were presented pairs of emotional words spoken with either statement or question intonation while their EEG was recorded. Their task was to judge whether the intonations were the same. Results: Emotional linguistic information did not facilitate amusics’ performance on the intonation-matching task, as their performance was significantly worse than that of controls. EEG results showed a reduced N2 response to incongruent intonation pairs in amusics compared with controls, which likely reflects impaired conflict processing in amusia. However, at an earlier processing stage, our EEG results indicate that amusics were intact in early sensory auditory processing, as revealed by a comparable N1 modulation in both groups. Conclusion: We propose that the impairment in discriminating speech intonation observed among amusic individuals may arise from an inability to access information extracted at early processing stages. This, in turn, could reflect a disconnection between low-level and high-level processing.

Music is a unique communication system for human beings. Iconic musical meaning is one dimension of musical meaning, which emerges from musical information resembling sounds of objects, qualities of objects, or qualities of abstract concepts. The present study investigated whether congenital amusia, a disorder of musical pitch perception, impacts the processing of iconic musical meaning. With a cross-modal semantic priming paradigm, target images were primed by semantically congruent or incongruent musical excerpts, which were characterized by direction (upward or downward) of pitch change (Experiment 1), or were selected from natural music (Experiment 2). Twelve Mandarin-speaking amusics and 12 controls performed a recognition (implicit) and a semantic congruency judgment (explicit) task while their EEG waveforms were recorded. Unlike controls, amusics failed to elicit an N400 effect when musical meaning was represented by direction of pitch change, regardless of the nature of the tasks (implicit versus explicit). However, the N400 effect in response to musical meaning in natural musical excerpts was observed for both the groups in both types of tasks. These results indicate that amusics are able to process iconic musical meaning through multiple acoustic cues in natural musical excerpts, but not through the direction of pitch change. This is the first study to investigate the processing of musical meaning in congenital amusia, providing evidence in support of the “melodic contour deafness hypothesis” with regard to iconic musical meaning processing in this disorder. [ABSTRACT FROM AUTHOR]

CONGENITAL AMUSIA IS A LIFELONG DISORDER OF musical processing for which no effective treatments have been found. The present study aimed to treat amusics' impairments in pitch direction identification through auditory training. Prior to training, twenty Chinese-speaking amusics and 20 matched controls were tested on the Montreal Battery of Evaluation of Amusia (MBEA) and two psychophysical pitch threshold tasks for identification of pitch direction in speech and music. Subsequently, ten of the twenty amusics undertook 10 sessions of adaptive-tracking pitch direction training, while the remaining 10 received no training. Post training, all amusics were retested on the pitch threshold tasks and on the three pitch-based MBEA subtests. Trained amusics demonstrated significantly improved thresholds for pitch direction identification in both speech and music, to the level of non-amusic control participants, although no significant difference was observed between trained and untrained amusics in the MBEA subtests. This provides the first clear positive evidence for improvement in pitch direction processing through auditory training in amusia. Further training studies are required to target different deficit areas in congenital amusia, so as to reveal which aspects of improvement will be most beneficial to the normal functioning of musical processing. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM PUBLISHER]

The past decade of research has provided compelling evidence that musical engagement is a fundamental human trait, and its biological basis is increasingly scrutinized. In this endeavor, the detailed study of individuals who have musical deficiencies is instructive because of likely neurogenetic underpinnings. Such individuals have ‘congenital amusia’, an umbrella term for lifelong musical disabilities that cannot be attributed to intellectual disability, lack of exposure, or brain damage after birth. Key points are reviewed here that have emerged during recent years regarding the neurobiology of the disorder, focusing on the importance of recurrent processing between the right inferior frontal cortex and the auditory cortex for conscious monitoring of musical pitch, and how this relates to developmental cognitive disorders in general. [ABSTRACT FROM AUTHOR]

Introduction: Congenital amusia is a developmental disorder associated with deficits in pitch height discrimination or in integrating pitch sequences into melodies. This quasi-experimental pilot study investigated whether there is an association between pitch and numerical processing deficits in congenital amusia. Since pitch height discrimination is considered a form of magnitude processing, we investigated whether individuals with amusia present an impairment in numerical magnitude processing, which would reflect damage to a generalized magnitude system. Alternatively, we investigated whether the numerical processing deficit would reflect a disconnection between nonsymbolic and symbolic number representations.Method: This study was conducted with 11 adult individuals with congenital amusia and a control comparison group of 6 typically developing individuals. Participants performed nonsymbolic and symbolic magnitude comparisons and number line tasks. Results were available from previous testing using the Montreal Battery of Evaluation of Amusia (MBEA) and a pitch change detection task (PCD).Results: Compared to the controls, individuals with amusia exhibited no significant differences in their performance on both the number line and the nonsymbolic magnitude tasks. Nevertheless, they showed significantly worse performance on the symbolic magnitude task. Moreover, individuals with congenital amusia, who presented worse performance in the Meter subtest, also presented less precise nonsymbolic numerical representation.Conclusions: The relationship between meter and nonsymbolic numerical discrimination could indicate a general ratio processing deficit. The finding of preserved nonsymbolic numerical magnitude discrimination and mental number line representations, with impaired symbolic number processing, in individuals with congenital amusia indicates that (a) pitch height and numerical magnitude processing may not share common neural representations, and (b) in addition to pitch processing, individuals with amusia may present a deficit in accessing nonsymbolic numerical representations from symbolic representations. The symbolic access deficit could reflect a widespread impairment in the establishment of cortico-cortical connections between association areas. [ABSTRACT FROM PUBLISHER]

While most normal hearing individuals can readily use prosodic information in spoken language to interpret the moods and feelings of conversational partners, people with congenital amusia report that they often rely more on facial expressions and gestures, a strategy that may compensate for deficits in auditory processing. In this investigation, we used EEG to examine the extent to which individuals with congenital amusia draw upon visual information when making auditory or audio-visual judgments. Event-related potentials (ERP) were elicited by a change in pitch (up or down) between two sequential tones paired with a change in spatial position (up or down) between two visually presented dots. The change in dot position was either congruent or incongruent with the change in pitch. Participants were asked to judge (1) the direction of pitch change while ignoring the visual information (AV implicit task), and (2) whether the auditory and visual changes were congruent (AV explicit task). In the AV implicit task, amusic participants performed significantly worse in the incongruent condition than control participants. ERPs showed an enhanced N2–P3 response to incongruent AV pairings for control participants, but not for amusic participants. However when participants were explicitly directed to detect AV congruency, both groups exhibited enhanced N2–P3 responses to incongruent AV pairings. These findings indicate that amusics are capable of extracting information from both modalities in an AV task, but are biased to rely on visual information when it is available, presumably because they have learned that auditory information is unreliable. We conclude that amusic individuals implicitly draw upon visual information when judging auditory information, even though they have the capacity to explicitly recognize conflicts between these two sensory channels. [ABSTRACT FROM AUTHOR]

WE EXAMINED EXPLICIT PROCESSING OF MUSICAL syntax and tonality in a group of Han Chinese Mandarin speakers with congenital amusia, and the extent to which pitch discrimination impairments were associated with syntax and tonality processing. In Experiment 1, we assessed whether congenital amusia is associated with impaired explicit processing of musical syntax. Congruity ratings were examined for syntactically regular or irregular endings in harmonic and melodic contexts. Unlike controls, amusic participants failed to explicitly distinguish regular from irregular endings in both contexts. Surprisingly, however, a concurrent manipulation of pitch distance did not affect the processing of musical syntax for amusics, and their impaired music-syntactic processing was uncorrelated with their pitch discrimination thresholds. In Experiment 2, we assessed tonality perception using a probe-tone paradigm. Recovery of the tonal hierarchy was less evident for the amusic group than for the control group, and this reduced sensitivity to tonality in amusia was also unrelated to poor pitch discrimination. These findings support the view that music structure is processed by cognitive and neural resources that operate independently of pitch discrimination, and that these resources are impaired in explicit judgments for individuals with congenital amusia. [ABSTRACT FROM AUTHOR]

Congenital amusia is a neurodevelopmental disorder of musical processing that also impacts subtle aspects of speech processing. It remains debated at what stage(s) of auditory processing deficits in amusia arise. In this study, we investigated whether amusia originates from impaired subcortical encoding of speech (in quiet and noise) and musical sounds in the brainstem. Fourteen Cantonese-speaking amusics and 14 matched controls passively listened to six Cantonese lexical tones in quiet, two Cantonese tones in noise (signal-to-noise ratios at 0 and 20 dB), and two cello tones in quiet while their frequency-following responses (FFRs) to these tones were recorded. All participants also completed a behavioral lexical tone identification task. The results indicated normal brainstem encoding of pitch in speech (in quiet and noise) and musical stimuli in amusics relative to controls, as measured by FFR pitch strength, pitch error, and stimulus-to-response correlation. There was also no group difference in neural conduction time or FFR amplitudes. Both groups demonstrated better FFRs to speech (in quiet and noise) than to musical stimuli. However, a significant group difference was observed for tone identification, with amusics showing significantly lower accuracy than controls. Analysis of the tone confusion matrices suggested that amusics were more likely than controls to confuse between tones that shared similar acoustic features. Interestingly, this deficit in lexical tone identification was not coupled with brainstem abnormality for either speech or musical stimuli. Together, our results suggest that the amusic brainstem is not functioning abnormally, although higher-order linguistic pitch processing is impaired in amusia. This finding has significant implications for theories of central auditory processing, requiring further investigations into how different stages of auditory processing interact in the human brain.

The advent of diffusion magnetic resonance imaging allows researchers to virtually dissect white matter fibre pathways in the brain in vivo. This, for example, allows us to characterize and quantify how fibre tracts differ across populations in health and disease, and change as a function of training. Based on diffusion MRI, prior literature reports the absence of the arcuate fasciculus (AF) in some control individuals and as well in those with congenital amusia. The complete absence of such a major anatomical tract is surprising given the subtle impairments that characterize amusia. Thus, we hypothesize that failure to detect the AF in this population may relate to the tracking algorithm used, and is not necessarily reflective of their phenotype. Diffusion data in control and amusic individuals were analyzed using three different tracking algorithms: deterministic and probabilistic, the latter either modeling two or one fibre populations. Across the three algorithms, we replicate prior findings of a left greater than right AF volume, but do not find group differences or an interaction. We detect the AF in all individuals using the probabilistic 2-fibre model, however, tracking failed in some control and amusic individuals when deterministic tractography was applied. These findings show that the ability to detect the AF in our sample is dependent on the type of tractography algorithm. This raises the question of whether failure to detect the AF in prior studies may be unrelated to the underlying anatomy or phenotype.

Beat deafness, a recently documented form of congenital amusia, provides a unique window into functional specialization of neural circuitry for the processing of musical stimuli: Beat-deaf individuals exhibit deficits that are specific to the detection of a regular beat in music and the ability to move along with a beat. Studies on the neural underpinnings of beat processing in the general population suggest that the auditory system is capable of pre-attentively generating a predictive model of upcoming sounds in a rhythmic pattern, subserved largely within auditory cortex and reflected in mismatch negativity (MMN) and P3 event-related potential (ERP) components. The current study examined these neural correlates of beat perception in two beat-deaf individuals, Mathieu and Marjorie, and a group of control participants under conditions in which auditory stimuli were either attended or ignored. Compared to control participants, Mathieu demonstrated reduced behavioral sensitivity to beat omissions in metrical patterns, and Marjorie showed a bias to identify irregular patterns as regular. ERP responses to beat omissions reveal an intact pre-attentive system for processing beat irregularities in cases of beat deafness, reflected in the MMN component, and provide partial support for abnormalities in later cognitive stages of beat processing, reflected in an unreliable P3b component exhibited by Mathieu--but not Marjorie--compared to control participants. P3 abnormalities observed in the current study resemble P3 abnormalities exhibited by individuals with pitch-based amusia, and are consistent with attention or auditory-motor coupling accounts of deficits in beat perception. [ABSTRACT FROM AUTHOR]

The association/dissociation of pitch processing between music and language is a long lasting debate. We examined this music-language relationship by investigating to what extent pitch deficits in these two domains were dissociable. We focused on a special neurodevelopmental pitch disorder — congenital amusia, which primarily affects musical pitch processing. Recent research has also revealed lexical tone deficits in speech among amusics. Approximately one-third of Mandarin amusics exhibits behavioural difficulties in lexical tone perception, which is known as tone agnosia. Using mismatch negativities (MMNs), our current work probed lexical tone encoding at the pre-attentive level among the Mandarin amusics with (tone agnosics) and without (pure amusics) behavioural lexical tone deficits compared with age- and IQ-matched controls. Relative to the controls and the pure amusics, the tone agnosics exhibited reduced MMNs specifically in response to lexical tone changes. Their tone-consonant MMNs were intact and similar to those of the other two groups. Moreover, the tone MMN reduction over the left hemisphere was tightly linked to behavioural insensitivity to lexical tone changes. The current study thus provides the first psychophysiological evidence of subgroup differences in lexical tone processing among Mandarin amusics and links amusics’ behavioural tone deficits to impaired pre-attentive tone processing. Despite the overall music pitch deficits, the subgroup differences in lexical tone processing in Mandarin-speaking amusics suggest dissociation of pitch deficits between music and speech. [ABSTRACT FROM AUTHOR]

Brain imaging studies highlighted structural differences in congenital amusia, a life-long perceptual disorder that is associated with pitch perception and pitch memory deficits. A functional anomaly characterized by decreased low gamma oscillations (30–40 Hz range) in the right dorsolateral prefrontal cortex (DLPFC) during pitch memory has been revealed recently. Thus, the present study investigates whether applying transcranial alternating current stimulation (tACS) at 35 Hz to the right DLPFC would improve pitch memory. Nine amusics took part in two tACS sessions (either 35 Hz or 90 Hz) and completed a pitch and visual memory task before and during stimulation. 35 Hz stimulation facilitated pitch memory significantly. No modulation effects were found with 90 Hz stimulation or on the visual task. While amusics showed a selective impairment of pitch memory before stimulation, the performance during 35 Hz stimulation was not significantly different to healthy controls anymore. Taken together, the study shows that modulating the right DLPFC with 35 Hz tACS in congenital amusia selectively improves pitch memory performance supporting the hypothesis that decreased gamma oscillations within the DLPFC are causally involved in disturbed pitch memory and highlight the potential use of tACS to interact with cognitive processes. [ABSTRACT FROM AUTHOR]

Congenital amusia is a neurodevelopmental disorder characterized by impaired pitch processing. Although pitch simultaneities are among the fundamental building blocks of Western tonal music, affective responses to simultaneities such as isolated dyads varying in consonance/dissonance or chords varying in major/minor quality have rarely been studied in amusic individuals. Thirteen amusics and thirteen matched controls enculturated to Western tonal music provided pleasantness ratings of sine-tone dyads and complex-tone dyads in piano timbre as well as perceived happiness/sadness ratings of sine-tone triads and complex-tone triads in piano timbre. Acoustical analyses of roughness and harmonicity were conducted to determine whether similar acoustic information contributed to these evaluations in amusics and controls. Amusic individuals' pleasantness ratings indicated sensitivity to consonance and dissonance for complex-tone (piano timbre) dyads and, to a lesser degree, sine-tone dyads, whereas controls showed sensitivity when listening to both tone types. Furthermore, amusic individuals showed some sensitivity to the happiness-major association in the complex-tone condition, but not in the sine-tone condition. Controls rated major chords as happier than minor chords in both tone types. Linear regression analyses revealed that affective ratings of dyads and triads by amusic individuals were predicted by roughness but not harmonicity, whereas affective ratings by controls were predicted by both roughness and harmonicity. We discuss affective sensitivity in congenital amusia in view of theories of affective responses to isolated chords in Western listeners. [ABSTRACT FROM AUTHOR]