Emotional prosody in congenital amusia: Impaired and spared processes

Musicality - Tuned to the melody of vocal emotions

Musicians outperform non-musicians in vocal emotion perception, likely because of increased sensitivity to acoustic cues, such as fundamental frequency (F0) and timbre. Yet, how musicians make use of these acoustic cues to perceive emotions, and how they might differ from non-musicians, is unclear. To address these points, we created vocal stimuli that conveyed happiness, fear, pleasure or sadness, either in all acoustic cues, or selectively in either F0 or timbre only. We then compared vocal emotion perception performance between professional/semi-professional musicians (N = 39) and non-musicians (N = 38), all socialized in Western music culture. Compared to non-musicians, musicians classified vocal emotions more accurately. This advantage was seen in the full and F0-modulated conditions, but was absent in the timbre-modulated condition indicating that musicians excel at perceiving the melody (F0), but not the timbre of vocal emotions. Further, F0 seemed more important than timbre for the recognition of all emotional categories. Additional exploratory analyses revealed a link between time-varying F0 perception in music and voices that was independent of musical training. Together, these findings suggest that musicians are particularly tuned to the melody of vocal emotions, presumably due to a natural predisposition to exploit melodic patterns.

Mandarin-Speaking Amusics' Online Recognition of Tone and Intonation

PURPOSE

Congenital amusia is a neurogenetic disorder of musical pitch processing. Its linguistic consequences have been examined separately for speech intonations and lexical tones. However, in a tonal language such as Chinese, the processing of intonations and lexical tones interacts with each other during online speech perception. Whether and how the musical pitch disorder might affect linguistic pitch processing during online speech perception remains unknown.

METHOD

We investigated this question with intonation (question vs. statement) and lexical tone (rising Tone 2 vs. falling Tone 4) identification tasks using the same set of sentences, comparing behavioral and event-related potential measurements between Mandarin-speaking amusics and matched controls. We specifically focused on the amusics without behavioral lexical tone deficits (the majority, i.e., pure amusics).

RESULTS

Results showed that, despite relative to normal performance when tested in word lexical tone test, pure amusics demonstrated inferior recognition than controls during sentence tone and intonation identification. Compared to controls, pure amusics had larger N400 amplitudes in question stimuli during tone task and smaller P600 amplitudes in intonation task.

CONCLUSION

These data indicate that musical pitch disorder affects both tone and intonation processing during sentence processing even for pure amusics, whose lexical tone processing was intact when tested with words.

Auditory cortex and beyond: Deficits in congenital amusia

Congenital amusia is a neuro-developmental disorder of music perception and production, with the observed deficits contrasting with the sophisticated music processing reported for the general population. Musical deficits within amusia have been hypothesized to arise from altered pitch processing, with impairments in pitch discrimination and, notably, short-term memory. We here review research investigating its behavioral and neural correlates, in particular the impairments at encoding, retention, and recollection of pitch information, as well as how these impairments extend to the processing of pitch cues in speech and emotion. The impairments have been related to altered brain responses in a distributed fronto-temporal network, which can be observed also at rest. Neuroimaging studies revealed changes in connectivity patterns within this network and beyond, shedding light on the brain dynamics underlying auditory cognition. Interestingly, some studies revealed spared implicit pitch processing in congenital amusia, showing the power of implicit cognition in the music domain. Building on these findings, together with audiovisual integration and other beneficial mechanisms, we outline perspectives for training and rehabilitation and the future directions of this research domain.

Tone Deafness in Music Does Not Preclude Distributional Learning of Nonnative Tonal Languages in Individuals With Congenital Amusia

PURPOSE

Previous studies have shown that individuals with congenital amusia exhibit deficient pitch processing across music and language domains. This study investigated whether adult Chinese-speaking listeners with amusia were still able to learn Thai lexical tones based on stimulus frequency of statistical distribution via distributional learning, despite their degraded lexical tone perception.

METHOD

Following a pretest-training-posttest design, 21 amusics and 23 typical, musically intact listeners were assigned into bimodal and unimodal distribution conditions. Listeners were asked to discriminate minimal pairs of Thai mid-level tone and falling tone superimposed on variable base syllables and uttered by different speakers. The perceptual accuracy for each test session and improvement from pretest to posttest were collected and analyzed between the two groups using generalized mixed-effects models.

RESULTS

When discriminating Thai lexical tones, amusics were less accurate than typical listeners. Nonetheless, similarly to control listeners, perceptual gains from pretest to posttest were observed in bimodally rather than unimodally trained amusics, as evidenced by both trained and nontrained test words.

CONCLUSIONS

Amusics are able to learn lexical tones in a second or foreign context of speech. This extends previous research by showing that amusics' distributional learning of linguistic pitch remains largely preserved despite their degraded pitch processing. It is thus likely that manifestations of amusia in speech could not result from their abnormal statistical learning mechanism. This study meanwhile provides a heuristic approach for future studies to apply this paradigm into amusics' treatment to mitigate their pitch-processing disorder.

The Mandarin Chinese auditory emotions stimulus database: A validated set of Chinese pseudo-sentences

Emotional prosody is fully embedded in language and can be influenced by the linguistic properties of a specific language. Considering the limitations of existing Chinese auditory stimulus database studies, we developed and validated an emotional auditory stimuli database composed of Chinese pseudo-sentences, recorded by six professional actors in Mandarin Chinese. Emotional expressions included happiness, sadness, anger, fear, disgust, pleasant surprise, and neutrality. All emotional categories were vocalized into two types of sentence patterns, declarative and interrogative. In addition, all emotional pseudo-sentences, except for neutral, were vocalized at two levels of emotional intensity: normal and strong. Each recording was validated with 40 native Chinese listeners in terms of the recognition accuracy of the intended emotion portrayal; finally, 4361 pseudo-sentence stimuli were included in the database. Validation of the database using a forced-choice recognition paradigm revealed high rates of emotional recognition accuracy. The detailed acoustic attributes of vocalization were provided and connected to the emotion recognition rates. This corpus could be a valuable resource for researchers and clinicians to explore the behavioral and neural mechanisms underlying emotion processing of the general population and emotional disturbances in neurological, psychiatric, and developmental disorders. The Mandarin Chinese auditory emotion stimulus database is available at the Open Science Framework ( https://osf.io/sfbm6/?view_only=e22a521e2a7d44c6b3343e11b88f39e3 ).

Individuals with congenital amusia remember music they like

Music is better recognized when it is liked. Does this association remain evident when music perception and memory are severely impaired, as in congenital amusia? We tested 11 amusic and 11 matched control participants, asking whether liking of a musical excerpt influences subsequent recognition. In an initial exposure phase, participants-unaware that their recognition would be tested subsequently-listened to 24 musical excerpts and judged how much they liked each excerpt. In the test phase that followed, participants rated whether they recognized the previously heard excerpts, which were intermixed with an equal number of foils matched for mode, tempo, and musical genre. As expected, recognition was in general impaired for amusic participants compared with control participants. For both groups, however, recognition was better for excerpts that were liked, and the liking enhancement did not differ between groups. These results contribute to a growing body of research that examines the complex interplay between emotions and cognitive processes. More specifically, they extend previous findings related to amusics' impairments to a new memory paradigm and suggest that (1) amusic individuals are sensitive to an aesthetic and subjective dimension of the music-listening experience, and (2) emotions can support memory processes even in a population with impaired music perception and memory.

Auditory emotion recognition deficits in schizophrenia: A systematic review and meta-analysis

BACKGROUND

Auditory emotion recognition (AER) deficits refer to the abnormal identification and interpretation of tonal or prosodic features that transmit emotional information in sounds or speech. Evidence suggests that AER deficits are related to the pathology of schizophrenia. However, the effect size of the deficit in specific emotional category recognition in schizophrenia and its association with psychotic symptoms have never been evaluated through a meta-analysis.

METHODS

A systematic search for literature published in English or Chinese until November 30, 2020 was conducted in PubMed, Embase, Web of Science, PsychINFO, and China National Knowledge Infrastructure (CNKI), WanFang and Weip Databases. AER differences between patients and healthy controls (HCs) were assessed by the standardized mean differences (SMDs). Subgroup analyses were conducted for the type of emotional stimuli and the diagnosis of schizophrenia or schizoaffective disorders (Sch/SchA). Meta-regression analyses were performed to assess the influence of patients' age, sex, illness duration, antipsychotic dose, positive and negative symptoms on the study SMDs.

RESULTS

Eighteen studies containing 615 psychosis (Sch/SchA) and 488 HCs were included in the meta-analysis. Patients exhibited moderate deficits in recognizing the neutral, happy, sad, angry, fear, disgust, and surprising emotion. Neither the semantic information in the auditory stimuli nor the diagnosis subtype affected AER deficits in schizophrenia. Sadness, anger, and disgust AER deficits were each positively associated with negative symptoms in schizophrenia.

CONCLUSIONS

Patients with schizophrenia have moderate AER deficits, which were associated with negative symptoms. Rehabilitation focusing on improving AER abilities may help improve negative symptoms and the long-term prognosis of schizophrenia.

Rapid Assessment of Non-Verbal Auditory Perception in Normal-Hearing Participants and Cochlear Implant Users

In the case of hearing loss, cochlear implants (CI) allow for the restoration of hearing. Despite the advantages of CIs for speech perception, CI users still complain about their poor perception of their auditory environment. Aiming to assess non-verbal auditory perception in CI users, we developed five listening tests. These tests measure pitch change detection, pitch direction identification, pitch short-term memory, auditory stream segregation, and emotional prosody recognition, along with perceived intensity ratings. In order to test the potential benefit of visual cues for pitch processing, the three pitch tests included half of the trials with visual indications to perform the task. We tested 10 normal-hearing (NH) participants with material being presented as original and vocoded sounds, and 10 post-lingually deaf CI users. With the vocoded sounds, the NH participants had reduced scores for the detection of small pitch differences, and reduced emotion recognition and streaming abilities compared to the original sounds. Similarly, the CI users had deficits for small differences in the pitch change detection task and emotion recognition, as well as a decreased streaming capacity. Overall, this assessment allows for the rapid detection of specific patterns of non-verbal auditory perception deficits. The current findings also open new perspectives about how to enhance pitch perception capacities using visual cues.

Comorbidity and cognitive overlap between developmental dyslexia and congenital amusia in children

Developmental dyslexia and congenital amusia are two specific neurodevelopmental disorders that affect reading and music perception, respectively. Similarities at perceptual, cognitive, and anatomical levels raise the possibility that a common factor is at play in their emergence, albeit in different domains. However, little consideration has been given to what extent they can co-occur. A first adult study suggested a 30% amusia rate in dyslexia and a 25% dyslexia rate in amusia (Couvignou et al., Cognitive Neuropsychology 2019). We present newly acquired data from 38 dyslexic and 38 typically developing children. These were assessed with literacy and phonological tests, as well as with three musical tests: the Montreal Battery of Evaluation of Musical Abilities, a pitch and time change detection task, and a singing task. Overall, about 34% of the dyslexic children were musically impaired, a proportion that is significantly higher than both the estimated 1.5-4% prevalence of congenital amusia in the general population and the rate of 5% observed within the control group. They were mostly affected in the pitch dimension, both in terms of perception and production. Correlations and prediction links were found between pitch processing skills and language measures after partialing out confounding factors. These findings are discussed with regard to cognitive and neural explanatory hypotheses of a comorbidity between dyslexia and amusia.

Emotion processing in congenital amusia: the deficits do not generalize to written emotion words

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.

Influence of Background Musical Emotions on Attention in Congenital Amusia

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.

Altered functional connectivity during speech perception in congenital amusia

Individuals with congenital amusia have a lifelong history of unreliable pitch processing. Accordingly, they downweight pitch cues during speech perception and instead rely on other dimensions such as duration. We investigated the neural basis for this strategy. During fMRI, individuals with amusia (N = 15) and controls (N = 15) read sentences where a comma indicated a grammatical phrase boundary. They then heard two sentences spoken that differed only in pitch and/or duration cues and selected the best match for the written sentence. Prominent reductions in functional connectivity were detected in the amusia group between left prefrontal language-related regions and right hemisphere pitch-related regions, which reflected the between-group differences in cue weights in the same groups of listeners. Connectivity differences between these regions were not present during a control task. Our results indicate that the reliability of perceptual dimensions is linked with functional connectivity between frontal and perceptual regions and suggest a compensatory mechanism.

Music processing deficits in Landau-Kleffner syndrome: Four case studies in adulthood

Verbal-auditory agnosia and aphasia are the most prominent symptoms in Landau-Kleffner syndrome (LKS), a childhood epilepsy that can have sustained long-term effects on language processing. The present study provides the first objective investigation of music perception skills in four adult patients with a diagnosis of LKS during childhood, covering the spectrum of severity of the syndrome from mild to severe. Pitch discrimination, short-term memory for melodic, rhythmic and verbal information, as well as emotion recognition in music and speech prosody were assessed with listening tests, and subjective attitude to music with a questionnaire. We observed amusia in 3 out of 4 patients, with elevated pitch discrimination thresholds and poor short-term memory for melody and rhythm. The two patients with the most severe LKS had impairments in music and prosody emotion recognition, but normal perception of emotional intensity of music. Overall, performance in music processing tasks was proportional to the severity of the syndrome. Nonetheless, the four patients reported that they enjoyed music, felt musical emotions, and used music in their daily life. These new data support the hypothesis that, beyond verbal impairments, cerebral networks involved in sound processing and encoding are deeply altered by the epileptic activity in LKS, well after electrophysiological normalization.