Improvisation is a novel tool to study musicality.

Humans spontaneously invent songs from an early age. Here, we exploit this natural inclination to probe implicit musical knowledge in 33 untrained and poor singers (amusia). Each sang 28 long improvisations as a response to a verbal prompt or a continuation of a melodic stem. To assess the extent to which each improvisation reflects tonality, which has been proposed to be a core organizational principle of musicality and which is present within most music traditions, we developed a new algorithm that compares a sung excerpt to a probability density function representing the tonal hierarchy of Western music. The results show signatures of tonality in both nonmusicians and individuals with congenital amusia, who have notorious difficulty performing musical tasks that require explicit responses and memory. The findings are a proof of concept that improvisation can serve as a novel, even enjoyable method for systematically measuring hidden aspects of musicality across the spectrum of musical ability.

The relationship between acoustic and musical pitch processing in adolescents.

Amusia is defined as a difficulty processing the tonal pitch structure of music such that an individual cannot tell the difference between notes that are in-key and out-of-key. A fine-grained pitch discrimination deficit is often observed in people with amusia. It is possible that an intervention, early in development, could mitigate amusia; however, one challenge identifying amusia early in development is that identifying in- and out-of-key notes is a metacognitive task. Given the common co-occurrence of difficulties with pitch discrimination, it would be easier to identify amusia in developing children by using a pitch change detection task. The goal of this study was to explore the behavioural and neurophysiological profiles of adolescents with poor pitch processing (Poor PP) abilities compared with those with normal pitch processing (Normal PP) abilities. Neurophysiologically, the Poor PPs exhibited a similar event-related potential (ERP) profile to adult amusics during both acoustic and musical pitch discrimination tasks. That is, early ERPs (ERAN, MMN) were similar in Poor PPs compared with Normal PPs, whereas late positivities (P300, P600) were absent in Poor PPs, but present in Normal PPs. At the same time, behavioural data revealed a double dissociation between the abilities to detect a pitch deviant in acoustic and musical context, suggesting that about a third of the children would be missed by selecting a fine-grained acoustic pitch discrimination task to identify the presence of amusia in early childhood.

The singing voice is special: Persistence of superior memory for vocal melodies despite vocal-motor distractions.

Vocal melodies sung without lyrics (la la) are remembered better than instrumental melodies. What causes the advantage? One possibility is that vocal music elicits subvocal imitation, which could promote enhanced motor representations of a melody. If this motor interpretation is correct, distracting the motor system during encoding should reduce the memory advantage for vocal over piano melodies. In Experiment 1, participants carried out movements of the mouth (i.e., chew gum) or hand (i.e., squeeze a beanbag) while listening to 24 unfamiliar folk melodies (half vocal, half piano). In a subsequent memory test, they rated the same melodies and 24 timbre-matched foils from '1-Definitely New' to '7-Definitely Old'. There was a memory advantage for vocal over piano melodies with no effect of group and no interaction. In Experiment 2, participants carried out motor activities during encoding more closely related to singing, either silently articulating (la la) or vocalizing without articulating (humming continuously). Once again, there was a significant advantage for vocal melodies with no effect or interaction of group. In Experiment 3, participants audibly whispered (la la) repeatedly during encoding. Again, the voice advantage was present and did not differ appreciably from prior research with no motor task during encoding. However, we observed that the spontaneous phase-locking of whisper rate and musical beat tended to predict enhanced memory for vocal melodies. Altogether the results challenge the notion that subvocal rehearsal of the melody drives enhanced memory for vocal melodies. Instead, the voice may enhance engagement.

Musical training improves the ability to understand speech-in-noise in older adults.

It is well known that hearing abilities decline with age, and one of the most commonly reported hearing difficulties reported in older adults is a reduced ability to understand speech in noisy environments. Older adult musicians have an enhanced ability to understand speech in noise, and this has been associated with enhanced brain responses related to both speech processing and the deployment of attention; however, the causal impact of music lessons in older adults has not yet been demonstrated. To investigate whether a causal relationship exists between short-term musical training and performance on auditory tests in older adults and to determine if musical training can be used to improve hearing in older adult nonmusicians, we conducted a longitudinal training study with random assignment. A sample of older adults was randomly assigned to learn to play piano (Music), to learn to play a visuospatially demanding video game (Video), or to serve as a no-contact control (No-contact). After 6 months, the Music group improved their ability to understand a word presented in loud background noise, whereas the other 2 groups did not. This improvement was related to an increase in positive-going electrical brain activity at fronto-left electrodes 200-1000 ms after the presentation of a word in noise. Source analyses suggest that this activity was due to sources located in the left inferior frontal gyrus and other regions involved in the speech-motor system. These findings support the idea that musical training provides a causal benefit to hearing abilities. Importantly, these findings suggest that musical training could be used as a foundation to develop auditory rehabilitation programs for older adults.

Decreased risk of falls in patients attending music sessions on an acute geriatric ward: results from a retrospective cohort study.

BACKGROUND: Music has been shown to improve health and quality of life. It was suggested that music may also have an impact on gait stability and fall risk. Yet, few studies have exploited music in the hospital setting, and even less so in the geriatric population. Our objective was to examine the influence of music listening on the risk of falls by comparing the Morse Fall Scale score in patients admitted to a Geriatric Assessment Unit (GAU) who attended music listening sessions and in patients who did not attend music sessions. METHODS: This was a retrospective cohort study (mean follow-up 13.3 ± 6.8 days) which took place in a GAU, St. Mary's Hospital Center, Montreal. A total of 152 charts of participants, with a mean age of 85.7 ± 6.4 years and 88.2% female were reviewed and included. There were 61 participants exposed to the music listening sessions group and 91 in the non-exposed group matched for age, sex, cause and season of admission, and living situation. One-hour music sessions were provided to the patients by volunteer musicians. The Morse Fall Scale score upon admission and discharge as well as its variation (change from before to after exposure) were used as outcomes. Age, sex, living situation, reason for admission, season of admission, Mini Mental Status Examination score, number of therapeutic classes taken daily upon admission, use of psychoactive drugs upon admission and length of stay were used as covariates. RESULTS: The Morse Fall Scale score decreased significantly in the exposed group compared to the non-exposed group (p = 0.025) and represented a small to medium-sized effect, d = 0.395. The multiple linear regression model showed a significant association between the decrease of the Morse Fall Scale score and music exposure (B = - 17.1, p = 0.043). CONCLUSION: Participating in music listening sessions was associated with a decreased risk of falls in patients admitted to a GAU. Further controlled research is necessary to confirm these findings and to determine the mechanisms by which music listening impacts fall risk. TRIAL REGISTRATION: Clinical trial registry: ClinicalTrials.gov . Registration number: NCT03348657 (November 17th, 2017). Retrospectively registered.

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

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

Recording the human brainstem frequency-following-response in the free-field.

BACKGROUND: The human auditory brainstem frequency-following response (FFR) is an objective measure used to investigate the brainstem's encoding ability of sounds. Traditionally, FFRs are recorded under close-field conditions (earphones), but free-field stimulations (loudspeaker) have yet to be attempted, which would increase the applications of FFRs by making this technique accessible to those who cannot wear inserted transducers. Here we test the feasibility and reliability of measuring speech ABRs across free and close-field. NEW METHOD: The FFR was evoked by a 40-ms consonant-vowel (cv) /da/ syllable which was presented in the standard close-field conditions with insert earphones, and in a novel free-field condition via a loudspeaker. RESULTS: A well-defined FFR was observed for each stimulating method (free or close-field). We show that it is possible and reliable to elicit FFRs from a speaker and that these do not systematically differ from those elicited by conventional earphones. COMPARISON WITH EXISTING METHOD: Neural responses were subjected to a comparative within-subjects analysis, using standard measures found in the literature in order to quantify and compare the intrinsic (amplitude, noise, consistency), acoustic (latency, spectral amplitude) and reliability properties (intraclass correlation coefficients and Bland and Altman limits of agreement) of the neural signal. CONCLUSIONS: Reliable FFRs can be elicited using free-field presentation with comparable to acoustical, intrinsic and reliability properties as those elicited by standard close-field presentations.

Effects of vocal training in a musicophile with congenital amusia.

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.

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.

Facial, vocal and musical emotion recognition is altered in paranoid schizophrenic patients.

Disturbed processing of emotional faces and voices is typically observed in schizophrenia. This deficit leads to impaired social cognition and interactions. In this study, we investigated whether impaired processing of emotions also affects musical stimuli, which are widely present in daily life and known for their emotional impact. Thirty schizophrenic patients and 30 matched healthy controls evaluated the emotional content of musical, vocal and facial stimuli. Schizophrenic patients are less accurate than healthy controls in recognizing emotion in music, voices and faces. Our results confirm impaired recognition of emotion in voice and face stimuli in schizophrenic patients and extend this observation to the recognition of emotion in musical stimuli.

Sensitivity to musical emotions in congenital amusia.

The emotional experience elicited by music is largely dependent on structural characteristics such as pitch, rhythm, and dynamics. We examine here to what extent amusic adults, who have experienced pitch perception difficulties all their lives, still maintain some ability to perceive emotions from music. Amusic and control participants judged the emotions expressed by unfamiliar musical clips intended to convey happiness, sadness, fear and peacefulness (Experiment 1A). Surprisingly, most amusic individuals showed normal recognition of the four emotions tested here. This preserved ability was not due to some peculiarities of the music, since the amusic individuals showed a typical deficit in perceiving pitch violations intentionally inserted in the same clips (Experiment 1B). In Experiment 2, we tested the use of two major structural determinants of musical emotions: tempo and mode. Neutralization of tempo had the same effect on both amusics' and controls' emotional ratings. In contrast, amusics did not respond to a change of mode as markedly as controls did. Moreover, unlike the control participants, amusics' judgments were not influenced by subtle differences in pitch, such as the number of semitones changed by the mode manipulation. Instead, amusics showed normal sensitivity to fluctuations in energy, to pulse clarity, and to timbre differences, such as roughness. Amusics even showed sensitivity to key clarity and to large mean pitch differences in distinguishing happy from sad music. Thus, the pitch perception deficit experienced by amusic adults had only mild consequences on emotional judgments. In sum, emotional responses to music may be possible in this condition.

Impairments in musical abilities reflected in the auditory brainstem: evidence from congenital amusia.

Congenital amusia is a neurogenetic condition, characterized by a deficit in music perception and production, not explained by hearing loss, brain damage or lack of exposure to music. Despite inferior musical performance, amusics exhibit normal auditory cortical responses, with abnormal neural correlates suggested to lie beyond auditory cortices. Here we show, using auditory brainstem responses to complex sounds in humans, that fine-grained automatic processing of sounds is impoverished in amusia. Compared with matched non-musician controls, spectral amplitude was decreased in amusics for higher harmonic components of the auditory brainstem response. We also found a delayed response to the early transient aspects of the auditory stimulus in amusics. Neural measures of spectral amplitude and response timing correlated with participants' behavioral assessments of music processing. We demonstrate, for the first time, that amusia affects how complex acoustic signals are processed in the auditory brainstem. This neural signature of amusia mirrors what is observed in musicians, such that the aspects of the auditory brainstem responses that are enhanced in musicians are degraded in amusics. By showing that gradients of music abilities are reflected in the auditory brainstem, our findings have implications not only for current models of amusia but also for auditory functioning in general.

The specificity of neural responses to music and their relation to voice processing: an fMRI-adaptation study.

Several studies have identified, using functional magnetic resonance imaging (fMRI), a region within the superior temporal gyrus that preferentially responds to musical stimuli. However, in most cases, significant responses to other complex stimuli, particularly human voice, were also observed. Thus, it remains unknown if the same neurons respond to both stimulus types, albeit with different strengths, or whether the responses observed with fMRI are generated by distinct, overlapping neural populations. To address this question, we conducted an fMRI experiment in which short music excerpts and human vocalizations were presented in a pseudo-random order. Critically, we performed an adaptation-based analysis in which responses to the stimuli were analyzed taking into account the category of the preceding stimulus. Our results confirm the presence of a region in the anterior STG that responds more strongly to music than voice. Moreover, we found a music-specific adaptation effect in this area, consistent with the existence of music-preferred neurons. Lack of differences between musicians and non-musicians argues against an expertise effect. These findings provide further support for neural separability between music and speech within the temporal lobe.

Attending to pitch information inhibits processing of pitch information: the curious case of amusia.

In normal listeners, the tonal rules of music guide musical expectancy. In a minority of individuals, known as amusics, the processing of tonality is disordered, which results in severe musical deficits. It has been shown that the tonal rules of music are neurally encoded, but not consciously available in amusics. Previous neurophysiological studies have not explicitly controlled the level of attention in tasks where participants ignored the tonal structure of the stimuli. Here, we test whether access to tonal knowledge can be demonstrated in congenital amusia when attention is controlled. Electric brain responses were recorded while asking participants to detect an individually adjusted near-threshold click in a melody. In half the melodies, a note was inserted that violated the tonal rules of music. In a second task, participants were presented with the same melodies but were required to detect the tonal deviation. Both tasks required sustained attention, thus conscious access to the rules of tonality was manipulated. In the click-detection task, the pitch deviants evoked an early right anterior negativity (ERAN) in both groups. In the pitch-detection task, the pitch deviants evoked an ERAN and P600 in controls but not in amusics. These results indicate that pitch regularities are represented in the cortex of amusics, but are not consciously available. Moreover, performing a pitch-judgment task eliminated the ERAN in amusics, suggesting that attending to pitch information interferes with perception of pitch. We propose that an impaired top-down frontotemporal projection is responsible for this disorder.

Cochlear implant users move in time to the beat of drum music.

Cochlear implant users show a profile of residual, yet poorly understood, musical abilities. An ability that has received little to no attention in this population is entrainment to a musical beat. We show for the first time that a heterogeneous group of cochlear implant users is able to find the beat and move their bodies in time to Latin Merengue music, especially when the music is presented in unpitched drum tones. These findings not only reveal a hidden capacity for feeling musical rhythm through the body in the deaf and hearing impaired population, but illuminate promising avenues for designing early childhood musical training that can engage implanted children in social musical activities with benefits potentially extending to non-musical domains.

The impact of musicianship on the cortical mechanisms related to separating speech from background noise.

Musicians have enhanced auditory processing abilities. In some studies, these abilities are paralleled by an improved understanding of speech in noisy environments, partially due to more robust encoding of speech signals in noise at the level of the brainstem. Little is known about the impact of musicianship on attention-dependent cortical activity related to lexical access during a speech-in-noise task. To address this issue, we presented musicians and nonmusicians with single words mixed with three levels of background noise, across two conditions, while monitoring electrical brain activity. In the active condition, listeners repeated the words aloud, and in the passive condition, they ignored the words and watched a silent film. When background noise was most intense, musicians repeated more words correctly compared with nonmusicians. Auditory evoked responses were attenuated and delayed with the addition of background noise. In musicians, P1 amplitude was marginally enhanced during active listening and was related to task performance in the most difficult listening condition. By comparing ERPs from the active and passive conditions, we isolated an N400 related to lexical access. The amplitude of the N400 was not influenced by the level of background noise in musicians, whereas N400 amplitude increased with the level of background noise in nonmusicians. In nonmusicians, the increase in N400 amplitude was related to a reduction in task performance. In musicians only, there was a rightward shift of the sources contributing to the N400 as the level of background noise increased. This pattern of results supports the hypothesis that encoding of speech in noise is more robust in musicians and suggests that this facilitates lexical access. Moreover, the shift in sources suggests that musicians, to a greater extent than nonmusicians, may increasingly rely on acoustic cues to understand speech in noise.

Capturing with EEG the neural entrainment and coupling underlying sensorimotor synchronization to the beat.

Synchronizing movements with rhythmic inputs requires tight coupling of sensory and motor neural processes. Here, using a novel approach based on the recording of steady-state-evoked potentials (SS-EPs), we examine how distant brain areas supporting these processes coordinate their dynamics. The electroencephalogram was recorded while subjects listened to a 2.4-Hz auditory beat and tapped their hand on every second beat. When subjects tapped to the beat, the EEG was characterized by a 2.4-Hz SS-EP compatible with beat-related entrainment and a 1.2-Hz SS-EP compatible with movement-related entrainment, based on the results of source analysis. Most importantly, when compared with passive listening of the beat, we found evidence suggesting an interaction between sensory- and motor-related activities when subjects tapped to the beat, in the form of (1) additional SS-EP appearing at 3.6 Hz, compatible with a nonlinear product of sensorimotor integration; (2) phase coupling of beat- and movement-related activities; and (3) selective enhancement of beat-related activities over the hemisphere contralateral to the tapping, suggesting a top-down effect of movement-related activities on auditory beat processing. Taken together, our results are compatible with the view that rhythmic sensorimotor synchronization is supported by a dynamic coupling of sensory and motor related activities.

Music listening engages specific cortical regions within the temporal lobes: differences between musicians and non-musicians.

Music and speech are two of the most relevant and common sounds in the human environment. Perceiving and processing these two complex acoustical signals rely on a hierarchical functional network distributed throughout several brain regions within and beyond the auditory cortices. Given their similarities, the neural bases for processing these two complex sounds overlap to a certain degree, but particular brain regions may show selectivity for one or the other acoustic category, which we aimed to identify. We examined 53 subjects (28 of them professional musicians) by functional magnetic resonance imaging (fMRI), using a paradigm designed to identify regions showing increased activity in response to different types of musical stimuli, compared to different types of complex sounds, such as speech and non-linguistic vocalizations. We found a region in the anterior portion of the superior temporal gyrus (aSTG) (planum polare) that showed preferential activity in response to musical stimuli and was present in all our subjects, regardless of musical training, and invariant across different musical instruments (violin, piano or synthetic piano). Our data show that this cortical region is preferentially involved in processing musical, as compared to other complex sounds, suggesting a functional role as a second-order relay, possibly integrating acoustic characteristics intrinsic to music (e.g., melody extraction). Moreover, we assessed whether musical experience modulates the response of cortical regions involved in music processing and found evidence of functional differences between musicians and non-musicians during music listening. In particular, bilateral activation of the planum polare was more prevalent, but not exclusive, in musicians than non-musicians, and activation of the right posterior portion of the superior temporal gyrus (planum temporale) differed between groups. Our results provide evidence of functional specialization for music processing in specific regions of the auditory cortex and show domain-specific functional differences possibly correlated with musicianship.

Distinct electrophysiological indices of maintenance in auditory and visual short-term memory.

We compared the electrophysiological correlates for the maintenance of non-musical tones sequences in auditory short-term memory (ASTM) to those for the short-term maintenance of sequences of coloured disks held in visual short-term memory (VSTM). The visual stimuli yielded a sustained posterior contralateral negativity (SPCN), suggesting that the maintenance of sequences of coloured stimuli engaged structures similar to those involved in the maintenance of simultaneous visual displays. On the other hand, maintenance of acoustic sequences produced a sustained negativity at fronto-central sites. This component is named the Sustained Anterior Negativity (SAN). The amplitude of the SAN increased with increasing load in ASTM and predicted individual differences in the performance. There was no SAN in a control condition with the same auditory stimuli but no memory task, nor one associated with visual memory. These results suggest that the SAN is an index of brain activity related to the maintenance of representations in ASTM that is distinct from the maintenance of representations in VSTM.