Widespread auditory deficits in tune deafness

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.

Auditory temporal resolution and backward masking in musicians with absolute pitch

Among the many questions regarding the ability to effortlessly name musical notes without a reference, also known as absolute pitch, the neural processes by which this phenomenon operates are still a matter of debate. Although a perceptual subprocess is currently accepted by the literature, the participation of some aspects of auditory processing still needs to be determined. We conducted two experiments to investigate the relationship between absolute pitch and two aspects of auditory temporal processing, namely temporal resolution and backward masking. In the first experiment, musicians were organized into two groups according to the presence of absolute pitch, as determined by a pitch identification test, and compared regarding their performance in the Gaps-in-Noise test, a gap detection task for assessing temporal resolution. Despite the lack of statistically significant difference between the groups, the Gaps-in-Noise test measures were significant predictors of the measures for pitch naming precision, even after controlling for possible confounding variables. In the second experiment, another two groups of musicians with and without absolute pitch were submitted to the backward masking test, with no difference between the groups and no correlation between backward masking and absolute pitch measures. The results from both experiments suggest that only part of temporal processing is involved in absolute pitch, indicating that not all aspects of auditory perception are related to the perceptual subprocess. Possible explanations for these findings include the notable overlap of brain areas involved in both temporal resolution and absolute pitch, which is not present in the case of backward masking, and the relevance of temporal resolution to analyze the temporal fine structure of sound in pitch perception.

The Perception of Lexical Tone and Intonation in Whispered Speech by Mandarin-Speaking Congenital Amusics

PURPOSE

A fundamental feature of human speech is variation, including the manner of phonation, as exemplified in the case of whispered speech. In this study, we employed whispered speech to examine an unresolved issue about congenital amusia, a neurodevelopmental disorder of musical pitch processing, which also affects speech pitch processing such as lexical tone and intonation perception. The controversy concerns whether amusia is a pitch-processing disorder or can affect speech processing beyond pitch.

METHOD

We examined lexical tone and intonation recognition in 19 Mandarin-speaking amusics and 19 matched controls in phonated and whispered speech, where fundamental frequency (f _o) information is either present or absent.

RESULTS

The results revealed that the performance of congenital amusics was inferior to that of controls in lexical tone identification in both phonated and whispered speech. These impairments were also detected in identifying intonation (statements/questions) in phonated and whispered modes. Across the experiments, regression models revealed that f _o and non-f _o (duration, intensity, and formant frequency) acoustic cues predicted tone and intonation recognition in phonated speech, whereas non-f _o cues predicted tone and intonation recognition in whispered speech. There were significant differences between amusics and controls in the use of both f _o and non-f _o cues.

CONCLUSION

The results provided the first evidence that the impairments of amusics in lexical tone and intonation identification prevail into whispered speech and support the hypothesis that the deficits of amusia extend beyond pitch processing.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.19302275.

Pitch and Rhythm Perception and Verbal Short-Term Memory in Acute Traumatic Brain Injury

Music perception deficits are common following acquired brain injury due to stroke, epilepsy surgeries, and aneurysmal clipping. Few studies have examined these deficits following traumatic brain injury (TBI), resulting in an under-diagnosis in this population. We aimed to (1) compare TBI patients to controls on pitch and rhythm perception during the acute phase; (2) determine whether pitch and rhythm perception disorders co-occur; (3) examine lateralization of injury in the context of pitch and rhythm perception; and (4) determine the relationship between verbal short-term memory (STM) and pitch and rhythm perception. Music perception was examined using the Scale and Rhythm tests of the Montreal Battery of Evaluation of Amusia, in association with CT scans to identify lesion laterality. Verbal short-term memory was examined using Digit Span Forward. TBI patients had greater impairment than controls, with 43% demonstrating deficits in pitch perception, and 40% in rhythm perception. Deficits were greater with right hemisphere damage than left. Pitch and rhythm deficits co-occurred 31% of the time, suggesting partly dissociable networks. There was a dissociation between performance on verbal STM and pitch and rhythm perception 39 to 42% of the time (respectively), with most individuals (92%) demonstrating intact verbal STM, with impaired pitch or rhythm perception. The clinical implications of music perception deficits following TBI are discussed.

Individuals with congenital amusia do not show context-dependent perception of tonal categories

Perceptual adaptation is an active cognitive process where listeners re-analyse speech categories based on new contexts/situations/talkers. It involves top-down influences from higher cortical levels on lower-level auditory processes. Individuals with congenital amusia have impaired pitch processing with reduced connectivity between frontal and temporal regions. This study examined whether deficits in amusia would lead to impaired perceptual adaptation in lexical tone perception. Thirteen Mandarin-speaking amusics and 13 controls identified the category of target tones on an 8-step continuum ranging from rising to high-level, either in isolation or in a high-/low-pitched context. For tones with no context, amusics exhibited reduced categorical perception than controls. While controls' lexical tone categorization demonstrated a significant context effect due to perceptual adaptation, amusics showed similar categorization patterns across both contexts. These findings suggest that congenital amusia impacts the extraction of context-dependent tonal categories in speech perception, indicating that perceptual adaptation may depend on listeners' perceptual acuity.

Talker normalization in typical Cantonese-speaking listeners and congenital amusics: Evidence from event-related potentials

Despite the lack of invariance in the mapping between the acoustic signal and phonological representation, typical listeners are capable of using information of a talker's vocal characteristics to recognize phonemes, a process known as "talker normalization". The current study investigated the time course of talker normalization in typical listeners and individuals with congenital amusia, a neurodevelopmental disorder of refined pitch processing. We examined the event-related potentials (ERPs) underling lexical tone processing in 24 Cantonese-speaking amusics and 24 typical listeners (controls) in two conditions: blocked-talker and mixed-talker conditions. The results demonstrated that for typical listeners, effects of talker variability can be observed as early as in the N1 time-window (100-150 ms), with the N1 amplitude reduced in the mixed-talker condition. Significant effects were also found in later components: the N2b/c peaked significantly earlier and the P3a and P3b amplitude was enhanced in the blocked-talker condition relative to the mixed-talker condition, especially for the tone pair that is more difficult to discriminate. These results suggest that the blocked-talker mode of stimulus presentation probably facilitates auditory processing and requires less attentional effort with easier speech categorization than the mixed-talker condition, providing neural evidence for the "active control theory". On the other hand, amusics exhibited comparable N1 amplitude to controls in both conditions, but deviated from controls in later components. They demonstrated overall later N2b/c peak latency significantly reduced P3a amplitude in the blocked-talker condition and reduced P3b amplitude irrespective of talker conditions. These results suggest that the amusic brain was intact in the auditory processing of talker normalization processes, as reflected by the comparable N1 amplitude, but exhibited reduced automatic attentional switch to tone changes in the blocked-talker condition, as captured by the reduced P3a amplitude, which presumably underlies a previously reported perceptual "anchoring" deficit in amusics. Altogether, these findings revealed the time course of talker normalization processes in typical listeners and extended the finding that conscious pitch processing is impaired in the amusic brain.

The Effects of Acoustic Variation on the Perception of Lexical Tone in Cantonese-Speaking Congenital Amusics

Purpose Congenital amusia is an inborn neurogenetic disorder of fine-grained pitch processing. This study attempted to pinpoint the impairment mechanism of speech processing in tonal language speakers with amusia. We designed a series of perception tasks aiming at selectively probing low-level pitch processing and relatively high-level phonological processing of lexical tones, with an aim to illuminate the deficiency mechanism underlying tone perception in amusia. Method Sixteen Cantonese-speaking amusics and 16 matched controls were tested on the effects of acoustic (talker/syllable) variations on the identification and discrimination of Cantonese tones in two conditions. In the low-variation condition, tones were always associated with the same talker or syllable; in the high-variation condition, tones were associated with either different talkers (with the syllable controlled) or different syllables (with the talker controlled). Results Largely similar results were obtained in talker and syllable variation conditions. Amusics exhibited overall poorer performance than controls in tone identification. Although amusics also demonstrated poorer performance in tone discrimination, the group difference was more obvious in low-variation conditions, where more acoustic constancy was provided. Besides, controls exhibited a greater increase in discrimination sensitivity from high- to low-variation conditions, implying a stronger benefit of acoustic constancy. Conclusions The findings suggested that amusics' lexical tone perception abilities, in terms of both low-level pitch processing and high-level phonological processing, as measured in low- and high-variation conditions, are impaired. Importantly, amusics were more impaired in taking advantage of low acoustic variation contexts and thus less efficiently sharpened their perception of tones when perceptual anchors in talker/syllable were provided, suggesting a possible "anchoring deficit" in congenital amusia. Supplemental Material https://doi.org/10.23641/asha.7616555.

Musical auditory processing, cognition, and psychopathology in 22q11.2 deletion syndrome

Chromosome 22q11.2 deletion syndrome (22q11DS) is associated with impairment in multiple domains of cognition and risk for several psychiatric disorders. Musical auditory processing is highly heritable, and is impaired in individuals with schizophrenia and other neurodevelopmental disorders, but has never been studied in 22q11DS, notwithstanding anecdotal evidence of its sparing. We aimed to characterize musical auditory processing in 22q11DS and explore potential relationships with other cognitive domains, musical engagement, and psychiatric disorders. The Distorted Tunes Task and Global Musical Sophistication Index were used to assess pitch discrimination and general musical engagement in 58 individuals with 22q11DS aged 8-29 years. Psychopathology was assessed with sections from the modified Schedule for Affective Disorders and Schizophrenia for School-Age Children and the Structured Interview for Prodromal Syndromes. The Penn computerized neurocognitive battery (CNB) examined four domains of cognition (executive functioning, episodic memory, complex cognition, and social cognition). Significant musical auditory processing impairment and reduced musical engagement were found in individuals with 22q11DS. However, deficits in musical auditory processing were not associated with reduced musical engagement. After covarying for age and sex, episodic memory and overall CNB performance accuracy were significantly related to performance in musical auditory processing. There were no relationships between musical auditory processing and presence of any psychiatric diagnoses. Individuals with 22q11DS experience significant deficits in musical auditory processing and reduced musical engagement. Pitch discrimination is associated with overall cognitive ability, but appears to be largely independent of psychiatric illness.

Context integration deficit in tone perception in Cantonese speakers with congenital amusia

Congenital amusia is a neuro-developmental disorder of pitch processing. This study investigated how this deficit affects lexical tone perception with and without context. Twenty-three Cantonese-speaking amusics and 23 controls were tested on the identification of high-variation tone stimuli in isolation vs in a carrier sentence. The controls generally achieved a higher accuracy with context than in isolation, suggesting that speech context facilitated tone identification. In contrast, amusics generally failed to benefit from the context, despite some variation among different tones. These findings provide insights into the underlying deficits of amusia, revealing a context integration deficit of tone perception in amusia.

Pitch perception and production in congenital amusia: Evidence from Cantonese speakers

This study investigated pitch perception and production in speech and music in individuals with congenital amusia (a disorder of musical pitch processing) who are native speakers of Cantonese, a tone language with a highly complex tonal system. Sixteen Cantonese-speaking congenital amusics and 16 controls performed a set of lexical tone perception, production, singing, and psychophysical pitch threshold tasks. Their tone production accuracy and singing proficiency were subsequently judged by independent listeners, and subjected to acoustic analyses. Relative to controls, amusics showed impaired discrimination of lexical tones in both speech and non-speech conditions. They also received lower ratings for singing proficiency, producing larger pitch interval deviations and making more pitch interval errors compared to controls. Demonstrating higher pitch direction identification thresholds than controls for both speech syllables and piano tones, amusics nevertheless produced native lexical tones with comparable pitch trajectories and intelligibility as controls. Significant correlations were found between pitch threshold and lexical tone perception, music perception and production, but not between lexical tone perception and production for amusics. These findings provide further evidence that congenital amusia is a domain-general language-independent pitch-processing deficit that is associated with severely impaired music perception and production, mildly impaired speech perception, and largely intact speech production.

Impaired encoding of rapid pitch information underlies perception and memory deficits in congenital amusia

Recent theories suggest that the basis of neurodevelopmental auditory disorders such as dyslexia or specific language impairment might be a low-level sensory dysfunction. In the present study we test this hypothesis in congenital amusia, a neurodevelopmental disorder characterized by severe deficits in the processing of pitch-based material. We manipulated the temporal characteristics of auditory stimuli and investigated the influence of the time given to encode pitch information on participants' performance in discrimination and short-term memory. Our results show that amusics' performance in such tasks scales with the duration available to encode acoustic information. This suggests that in auditory neuro-developmental disorders, abnormalities in early steps of the auditory processing can underlie the high-level deficits (here musical disabilities). Observing that the slowing down of temporal dynamics improves amusics' pitch abilities allows considering this approach as a potential tool for remediation in developmental auditory disorders.

Altered retrieval of melodic information in congenital amusia: insights from dynamic causal modeling of MEG data

Congenital amusia is a neuro-developmental disorder that primarily manifests as a difficulty in the perception and memory of pitch-based materials, including music. Recent findings have shown that the amusic brain exhibits altered functioning of a fronto-temporal network during pitch perception and short-term memory. Within this network, during the encoding of melodies, a decreased right backward frontal-to-temporal connectivity was reported in amusia, along with an abnormal connectivity within and between auditory cortices. The present study investigated whether connectivity patterns between these regions were affected during the short-term memory retrieval of melodies. Amusics and controls had to indicate whether sequences of six tones that were presented in pairs were the same or different. When melodies were different only one tone changed in the second melody. Brain responses to the changed tone in "Different" trials and to its equivalent (original) tone in "Same" trials were compared between groups using Dynamic Causal Modeling (DCM). DCM results confirmed that congenital amusia is characterized by an altered effective connectivity within and between the two auditory cortices during sound processing. Furthermore, right temporal-to-frontal message passing was altered in comparison to controls, with notably an increase in "Same" trials. An additional analysis in control participants emphasized that the detection of an unexpected event in the typically functioning brain is supported by right fronto-temporal connections. The results can be interpreted in a predictive coding framework as reflecting an abnormal prediction error sent by temporal auditory regions towards frontal areas in the amusic brain.

Boosting pitch encoding with audiovisual interactions in congenital amusia

The combination of information across senses can enhance perception, as revealed for example by decreased reaction times or improved stimulus detection. Interestingly, these facilitatory effects have been shown to be maximal when responses to unisensory modalities are weak. The present study investigated whether audiovisual facilitation can be observed in congenital amusia, a music-specific disorder primarily ascribed to impairments of pitch processing. Amusic individuals and their matched controls performed two tasks. In Task 1, they were required to detect auditory, visual, or audiovisual stimuli as rapidly as possible. In Task 2, they were required to detect as accurately and as rapidly as possible a pitch change within an otherwise monotonic 5-tone sequence that was presented either only auditorily (A condition), or simultaneously with a temporally congruent, but otherwise uninformative visual stimulus (AV condition). Results of Task 1 showed that amusics exhibit typical auditory and visual detection, and typical audiovisual integration capacities: both amusics and controls exhibited shorter response times for audiovisual stimuli than for either auditory stimuli or visual stimuli. Results of Task 2 revealed that both groups benefited from simultaneous uninformative visual stimuli to detect pitch changes: accuracy was higher and response times shorter in the AV condition than in the A condition. The audiovisual improvements of response times were observed for different pitch interval sizes depending on the group. These results suggest that both typical listeners and amusic individuals can benefit from multisensory integration to improve their pitch processing abilities and that this benefit varies as a function of task difficulty. These findings constitute the first step towards the perspective to exploit multisensory paradigms to reduce pitch-related deficits in congenital amusia, notably by suggesting that audiovisual paradigms are effective in an appropriate range of unimodal performance.

Phonological processing in Mandarin speakers with congenital amusia

Although there is an emerging consensus that both musical and linguistic pitch processing can be problematic for individuals with a developmental disorder termed congenital amusia, the nature of such a pitch-processing deficit, especially that demonstrated in a speech setting, remains unclear. Therefore, this study tested the performance of native Mandarin speakers, both with and without amusia, on discrimination and imitation tasks for Cantonese level tones, aiming to shed light on this issue. Results suggest that the impact of the phonological deficit, coupled with that of the domain-general pitch deficit, could provide a more comprehensive interpretation of Mandarin amusics' speech impairment. Specifically, when there was a high demand for pitch sensitivity, as in fine-grained pitch discriminations, the operation of the pitch-processing deficit played the more predominant role in modulating amusics' speech performance. But when the demand was low, as in discriminating naturally produced Cantonese level tones, the impact of the phonological deficit was more pronounced compared to that of the pitch-processing deficit. However, despite their perceptual deficits, Mandarin amusics' imitation abilities were comparable to controls'. Such selective impairment in tonal perception suggests that the phonological deficit more severely implicates amusics' input pathways.

(A)musicality in Williams syndrome: examining relationships among auditory perception, musical skill, and emotional responsiveness to music

Williams syndrome (WS), a genetic, neurodevelopmental disorder, is of keen interest to music cognition researchers because of its characteristic auditory sensitivities and emotional responsiveness to music. However, actual musical perception and production abilities are more variable. We examined musicality in WS through the lens of amusia and explored how their musical perception abilities related to their auditory sensitivities, musical production skills, and emotional responsiveness to music. In our sample of 73 adolescents and adults with WS, 11% met criteria for amusia, which is higher than the 4% prevalence rate reported in the typically developing (TD) population. Amusia was not related to auditory sensitivities but was related to musical training. Performance on the amusia measure strongly predicted musical skill but not emotional responsiveness to music, which was better predicted by general auditory sensitivities. This study represents the first time amusia has been examined in a population with a known neurodevelopmental genetic disorder with a range of cognitive abilities. Results have implications for the relationships across different levels of auditory processing, musical skill development, and emotional responsiveness to music, as well as the understanding of gene-brain-behavior relationships in individuals with WS and TD individuals with and without amusia.

Differential recognition of pitch patterns in discrete and gliding stimuli in congenital amusia: evidence from Mandarin speakers

This study examined whether "melodic contour deafness" (insensitivity to the direction of pitch movement) in congenital amusia is associated with specific types of pitch patterns (discrete versus gliding pitches) or stimulus types (speech syllables versus complex tones). Thresholds for identification of pitch direction were obtained using discrete or gliding pitches in the syllable /ma/ or its complex tone analog, from nineteen amusics and nineteen controls, all healthy university students with Mandarin Chinese as their native language. Amusics, unlike controls, had more difficulty recognizing pitch direction in discrete than in gliding pitches, for both speech and non-speech stimuli. Also, amusic thresholds were not significantly affected by stimulus types (speech versus non-speech), whereas controls showed lower thresholds for tones than for speech. These findings help explain why amusics have greater difficulty with discrete musical pitch perception than with speech perception, in which continuously changing pitch movements are prevalent.

The mechanism of speech processing in congenital amusia: evidence from Mandarin speakers

Congenital amusia is a neuro-developmental disorder of pitch perception that causes severe problems with music processing but only subtle difficulties in speech processing. This study investigated speech processing in a group of Mandarin speakers with congenital amusia. Thirteen Mandarin amusics and thirteen matched controls participated in a set of tone and intonation perception tasks and two pitch threshold tasks. Compared with controls, amusics showed impaired performance on word discrimination in natural speech and their gliding tone analogs. They also performed worse than controls on discriminating gliding tone sequences derived from statements and questions, and showed elevated thresholds for pitch change detection and pitch direction discrimination. However, they performed as well as controls on word identification, and on statement-question identification and discrimination in natural speech. Overall, tasks that involved multiple acoustic cues to communicative meaning were not impacted by amusia. Only when the tasks relied mainly on pitch sensitivity did amusics show impaired performance compared to controls. These findings help explain why amusia only affects speech processing in subtle ways. Further studies on a larger sample of Mandarin amusics and on amusics of other language backgrounds are needed to consolidate these results.

Relating pitch awareness to phonemic awareness in children: implications for tone-deafness and dyslexia

Language and music are complex cognitive and neural functions that rely on awareness of one's own sound productions. Information on the awareness of vocal pitch, and its relation to phonemic awareness which is crucial for learning to read, will be important for understanding the relationship between tone-deafness and developmental language disorders such as dyslexia. Here we show that phonemic awareness skills are positively correlated with pitch perception–production skills in children. Children between the ages of seven and nine were tested on pitch perception and production, phonemic awareness, and IQ. Results showed a significant positive correlation between pitch perception–production and phonemic awareness, suggesting that the relationship between musical and linguistic sound processing is intimately linked to awareness at the level of pitch and phonemes. Since tone-deafness is a pitch-related impairment and dyslexia is a deficit of phonemic awareness, we suggest that dyslexia and tone-deafness may have a shared and/or common neural basis.

Auditory and cognitive deficits associated with acquired amusia after stroke: a magnetoencephalography and neuropsychological follow-up study

Acquired amusia is a common disorder after damage to the middle cerebral artery (MCA) territory. However, its neurocognitive mechanisms, especially the relative contribution of perceptual and cognitive factors, are still unclear. We studied cognitive and auditory processing in the amusic brain by performing neuropsychological testing as well as magnetoencephalography (MEG) measurements of frequency and duration discrimination using magnetic mismatch negativity (MMNm) recordings. Fifty-three patients with a left (n = 24) or right (n = 29) hemisphere MCA stroke (MRI verified) were investigated 1 week, 3 months, and 6 months after the stroke. Amusia was evaluated using the Montreal Battery of Evaluation of Amusia (MBEA). We found that amusia caused by right hemisphere damage (RHD), especially to temporal and frontal areas, was more severe than amusia caused by left hemisphere damage (LHD). Furthermore, the severity of amusia was found to correlate with weaker frequency MMNm responses only in amusic RHD patients. Additionally, within the RHD subgroup, the amusic patients who had damage to the auditory cortex (AC) showed worse recovery on the MBEA as well as weaker MMNm responses throughout the 6-month follow-up than the non-amusic patients or the amusic patients without AC damage. Furthermore, the amusic patients both with and without AC damage performed worse than the non-amusic patients on tests of working memory, attention, and cognitive flexibility. These findings suggest domain-general cognitive deficits to be the primary mechanism underlying amusia without AC damage whereas amusia with AC damage is associated with both auditory and cognitive deficits.

Memory for pitch in congenital amusia: beyond a fine-grained pitch discrimination problem

Congenital amusia is a disorder that affects the perception and production of music. While amusia has been associated with deficits in pitch discrimination, several reports suggest that memory deficits also play a role. The present study investigated short-term memory span for pitch-based and verbal information in 14 individuals with amusia and matched controls. Analogous adaptive-tracking procedures were used to generate tone and digit spans using stimuli that exceeded psychophysically measured pitch perception thresholds. Individuals with amusia had significantly smaller tone spans, whereas their digits spans were a similar size to those of controls. An automated operation span task was used to determine working memory capacity. Working memory deficits were seen in only a small subgroup of individuals with amusia. These findings support the existence of a pitch-specific component within short-term memory and suggest that congenital amusia is more than a disorder of fine-grained pitch discrimination.

Central auditory disorders: toward a neuropsychology of auditory objects

PURPOSE OF REVIEW

Analysis of the auditory environment, source identification and vocal communication all require efficient brain mechanisms for disambiguating, representing and understanding complex natural sounds as 'auditory objects'. Failure of these mechanisms leads to a diverse spectrum of clinical deficits. Here we review current evidence concerning the phenomenology, mechanisms and brain substrates of auditory agnosias and related disorders of auditory object processing.

RECENT FINDINGS

Analysis of lesions causing auditory object deficits has revealed certain broad anatomical correlations: deficient parsing of the auditory scene is associated with lesions involving the parieto-temporal junction, while selective disorders of sound recognition occur with more anterior temporal lobe or extra-temporal damage. Distributed neural networks have been increasingly implicated in the pathogenesis of such disorders as developmental dyslexia, congenital amusia and tinnitus. Auditory category deficits may arise from defective interaction of spectrotemporal encoding and executive and mnestic processes. Dedicated brain mechanisms are likely to process specialized sound objects such as voices and melodies.

SUMMARY

Emerging empirical evidence suggests a clinically relevant, hierarchical and modular neuropsychological model of auditory object processing that provides a framework for understanding auditory agnosias and makes specific predictions to direct future work.

Free will debates: Simple experiments are not so simple

The notion that free will is an illusion has achieved such wide acceptance among philosophers and neuroscientists that it seems to be acquiring the status of dogma. Nonetheless, research in this area continues, and this review offers a new analysis of the design limitations and data interpretations of free-will experiments. This review presents 12 categories of questionable conclusions that some scholars use to promote the idea that free will is an illusion. The next generation of less ambiguous experiments is proposed.

Intonation processing in congenital amusia: discrimination, identification and imitation

This study investigated whether congenital amusia, a neuro-developmental disorder of musical perception, also has implications for speech intonation processing. In total, 16 British amusics and 16 matched controls completed five intonation perception tasks and two pitch threshold tasks. Compared with controls, amusics showed impaired performance on discrimination, identification and imitation of statements and questions that were characterized primarily by pitch direction differences in the final word. This intonation-processing deficit in amusia was largely associated with a psychophysical pitch direction discrimination deficit. These findings suggest that amusia impacts upon one's language abilities in subtle ways, and support previous evidence that pitch processing in language and music involves shared mechanisms.

Phonological processing in adults with deficits in musical pitch recognition

We identified individuals with deficits in musical pitch recognition by screening a large random population using the Distorted Tunes Test (DTT), and enrolled individuals who had DTT scores in the lowest 10th percentile, classified as tune deaf. We examined phonological processing abilities in 35 tune deaf and 34 normal control individuals. Eight different tests of phonological processing, including auditory word discrimination, syllable segmentation, and the Comprehensive Test of Phonological Processing (CTOPP) were administered to both groups. The tune deaf group displayed lower phonological and phonemic awareness abilities on all measures. Our results indicate that poor performance on the DTT is associated with deficits in processing speech sounds. These findings support the hypothesis that processing of speech sounds and musical sounds share common elements, and that tune deafness may be viewed as a syndromic disorder, frequently accompanied by deficits in a number of aspects of sound processing not specific to music.

LEARNING OUTCOMES

The reader will (1) understand the broad range of deficits in phonological perception and processing that accompany deficits in musical pitch recognition, and (2) recognize the possible utility of musical evaluation measures and music-based therapies in the treatment of phonological and other speech disorders.