Auditory World Research Articles

Music Perception in Children With Cochlear Implants

AbstractAs a result of the widespread use of cochlear implants, individuals with profound hearing loss now are able to hear sounds ranging from a syllable to a symphony. This form of “electric hearing” has been remarkably successful in providing sound to the deaf population and at least 100,000 implantation procedures have been performed worldwide in more than 80 countries (Clark, 2008). Today, it is routine for post-lingual deafened individuals (one who lost their hearing after normal childhood language acquisition) to achieve high performance on language tests following implantation (Lalwani, Larky, Wareing, Kwast, & Schindler, 1998). Deaf children implanted at an early age with a CI usually develop excellent spoken language skills, with placement into mainstream educational schooling (Francis, Koch, Wyatt, & Niparko, 1999). The overwhelming emphasis on language perception in CI users has led to relative neglect of non-linguistic sound perception. Yet, the auditory world consists of many other sounds besides those of spoken language. Of all non-linguistic sounds, perception of music—particularly pitch and timbre—represents the greatest challenge for implant-mediated listening (Limb, 2006). High-level perception of music rarely is attained through conventional speech processing technology in adults or children. Recent technological advances, however, have increased the processing capabilities of modern CIs and hold great promise for music perception and quality of life for children with cochlear implants (Lassaletta et al., 2007).

The Musician's Auditory World

The Musician's Auditory World

Musically Speaking: Exploring Music Instruction with Teachers of Students who are Visually Impaired

If you had been alive in May of 1890, you might have noticed a brief article in The New York Times that described the 59th anniversary celebration of the New York Institution for the Blind. The article, recently reprised in the Internet archives of the Times, was entitled Instructing Blind Children: Remarkable Results Attained in Music and Other Studies. It included the following excerpt. The entertainment was provided by about one hundred boys and girls from various classes. The programme was largely musical, for is everywhere recognized as an curriculum for the blind, because it not only affords pupils almost their pleasure, but provides the best means for thorough mental training and culture. This was shown by the heartiness and tunefulness of the chorus singing and the excellence of the class and individual work illustrating the training of the ear in the study of harmony. The article is replete with excessive cheerfulness and stereotypical assumptions, including the belief that is almost the sole pleasure of students, whose lives would surely be miserable without it. In spite of such trite assumptions, however, the core statement that music is everywhere recognized as an curriculum for the blind is an idea worth revisiting. In contrast with the message of this article, instruction for visually impaired students in today's educational environment is not often viewed as an essential curriculum. Many professionals in the field of visual impairment maintain a cautious distance from the role of instruction for their students. Often there is not enough time to include sufficient instruction due to the importance of academics in a student's daily schedule. Sometimes opportunities are missed because teachers are not personally skilled in and do not know how to support their students' musical interests. For these and other reasons, discussion of instruction or activities is often not included in meetings with educational or rehabilitation teams. In an effort to avoid typecasting of people as musically talented, some realities of their auditory world may be overlooked. Neurological research indicates that a larger area in the brains of people who are compared to those of sighted subjects is responsive to auditory stimuli, often resulting in functional advantages in localization and attention to sound (Elbert, Sterr, Rockstroh, Pantev, Muller, & Taub, 2002). Further, absolute pitch is more common among people who are (Sacks, 2007); one study found that 57% of study participants had absolute pitch, as compared with 20% of the general population (Hamilton, Pascual-Leone, & Schlaug, 2004). …

Extraction of the mismatch negativity elicited by sound duration decrements: A comparison of three procedures

This study focuses on comparison of procedures for extracting the brain event-related potentials (ERPs) – brain responses to stimuli recorded using electroencephalography (EEG). These responses are used to study how the synchronization of brain electrical responses is associated with cognition such as how the brain detects changes in the auditory world. One such event-related response to auditory change is called mismatch negativity (MMN). It is typically observed by computing a difference wave between ERPs elicited by a frequently repeated sound and ERPs elicited by an infrequently occurring sound which differs from the repeated sounds. Fast and reliable extraction of the ERPs, such as the genuine MMN, is an important focus of studies devoted to basic cognitive brain research. In this study, we compared three procedures for extraction of the MMN elicited by infrequent duration decrements in auditory sound stimulation. These were the conventional difference wave (DW) with average standard sweep, optimal digital filtering (ODF), and recently proposed independent component analysis (ICA) decomposition procedures. The statistical comparison was made in a group of 12 healthy adults aged 23–30 years. The MMN was elicited in a passive oddball protocol presenting an auditory stimulation consisting of frequent tones of 600 Hz of 100 ms duration each (standard stimuli). Infrequently, one of the tones was shortened to 75, 50, or 30 ms (deviant stimuli). The ICA decomposition procedure, similarly to the DW procedure with average standard sweep, extracted a cleaner MMN compared to the ODF procedure. Both procedures extracted the MMN, whose amplitude and latency characteristics concur with substantial number of publications in contrast to the ODF procedure.

Relevance of psychoacoustical theory.

Historically, the principles of psychoacoustics have been described in terms of mathematical theories. Are such mathematical theories now obsolete? Have they been replaced by computer algorithms? Do contemporary answers now come from simulations in computational toolboxes? The case for psychoacoustical theory can be made anew: Mathematical psychoacoustical theory has value because of the transparency of its assumptions and the universality of its language. It has an unparalleled ability to inspire extensions and revisions in order to evolve. It illuminates new conceptual directions through analogies with other sciences subserved by similar mathematical structures. Theory consolidates large amounts of otherwise unrelated data and serves as a guide to future experiments. Mathematical theory is the practical realization of images about the way the auditory world works, images that promote understanding because of their intuitive appeal. Theory is at its best when the ordinary operations of mathematics transform an initial model into logically inescapable new insights unlikely to have arisen by other avenues. [Work supported by the NIDCD, Grant DC-00181.]

Tiger moths and the threat of bats: decision-making based on the activity of a single sensory neuron

Echolocating bats and eared moths are a model system of predator-prey interaction within an almost exclusively auditory world. Through selective pressures from aerial-hawking bats, noctuoid moths have evolved simple ears that contain one to two auditory neurons and function to detect bat echolocation calls and initiate defensive flight behaviours. Among these moths, some chemically defended and mimetic tiger moths also produce ultrasonic clicks in response to bat echolocation calls; these defensive signals are effective warning signals and may interfere with bats' ability to process echoic information. Here, we demonstrate that the activity of a single auditory neuron (the A1 cell) provides sufficient information for the toxic dogbane tiger moth, Cycnia tenera, to decide when to initiate defensive sound production in the face of bats. Thus, despite previous suggestions to the contrary, these moths' only other auditory neuron, the less sensitive A2 cell, is not necessary for initiating sound production. However, we found a positive linear relationship between combined A1 and A2 activity and the number of clicks the dogbane tiger moth produces.

The Vestibulo-Auricular Reflex

The mammalian orienting response to sounds consists of a gaze shift that can be a combination of head and eye movements. In animals with mobile pinnae, the ears also move. During head movements, vision is stabilized by compensatory rotations of the eyeball within the head because of the vestibulo-ocular reflex (VOR). While studying the gaze shifts made by cats to sounds, a previously uncharacterized compensatory movement was discovered. The pinnae exhibited short-latency, goal-directed movements that reached their target while the head was still moving. The pinnae maintained a fixed position in space by counter-rotating on the head with an equal but opposite velocity to the head movement. We call these compensatory ear movements the vestibulo-auricular reflex (VAR) because they shared many kinematic characteristics with the VOR. Control experiments ruled out efference copy of head position signals and acoustic tracking (audiokinetic) of the source as the cause of the response. The VAR may serve to stabilize the auditory world during head movements.

One sound or two? Object-related negativity indexes echo perception

The ability to isolate a single sound source among concurrent sources and reverberant energy is necessary for understanding the auditory world. The precedence effect describes a related experimental finding, that when presented with identical sounds from two locations with a short onset asynchrony (on the order of milliseconds), listeners report a single source with a location dominated by the lead sound. Single-cell recordings in multiple animal models have indicated that there are low-level mechanisms that may contribute to the precedence effect, yet psychophysical studies in humans have provided evidence that top-down cognitive processes have a great deal of influence on the perception of simulated echoes. In the present study, event-related potentials evoked by click pairs at and around listeners' echo thresholds indicate that perception of the lead and lag sound as individual sources elicits a negativity between 100 and 250 msec, previously termed the object-related negativity (ORN). Even for physically identical stimuli, the ORN is evident when listeners report hearing, as compared with not hearing, a second sound source. These results define a neural mechanism related to the conscious perception of multiple auditory objects.

The perceptual and cognitive nonlinearities underlying musical preference across multiple exposures

Repetition is a fundamental part of engagement with the auditory world. Repeated exposures influence what gets perceived as important and what features are singled out for attention. That repetition can also influence the mysterious phenomenon of aesthetic enjoyment is a longstanding observation to which much intellectual attention has been paid. A special case of repetition and perceptual learning is music, a domain in which people choose to be exposed to the identical stimulus again and again. This apparent preference for repeated exposures connects fundamentally to notions of human identity, affect, cognitive processing, and neural function. We report on a set of experiments that uses behavioral measures to assess perceptual changes across multiple exposures (five over one week) of a 20‐minute piece for orchestra. Across the five exposures, we found an inverted U‐shape preference response, which possibly is decomposable to the complex interaction of multiple nonlinear components, represented by performance on tasks relating to memory, attention, affect, syntax, and error detection We argue that musical preference has remained a puzzle because the behavior depends on an underlying complex system with numerous nonlinear cognitive components revealed by our results. [Work supported by NIH, NSF, and Northwestern University.]

Object‐related negativity indexes perception of sounds beyond the echo threshold

The ability to isolate a single sound source among concurrent sources and reverberant energy is crucial for understanding the auditory world. The precedence effect describes an experimental finding that when listeners are presented with identical sounds from two locations with a short onset asynchrony, they report hearing a single source with a location dominated by the lead sound. We recently showed that event‐related potentials (ERPs) elicited by click pairs differ for trials on which listeners do and do not report hearing the lag sound as a separate source. Specifically, when participants report hearing two sounds, we observe a negativity between 100 and 250 ms, previously termed the object‐related negativity (ORN). These results indicate that the precedence effect reflects top‐down cognitive influence over early neurosensory processing. Additionally, the study provides support for the claim that the ORN, initially reported for sounds perceived as two concurrent pitches, indexes auditory object perception. The effects on the ORN of repeating identical click pairs, a condition that has previously been shown to increase echo thresholds, will also be discussed in the context of listeners forming complex models of room acoustics based on what they hear in a specific setting.

De la perception à l’apprentissage

In the field of perception, learning is formed by a distributed functional architecture of very specialized cortical areas. For example, capacities of learning in patients with visual deficits - hemianopia or visual agnosia - from cerebral lesions are limited by perceptual abilities. Moreover a visual deficit in link with abnormal perception may be associated with an alteration of representations in long term (semantic) memory. Furthermore, perception and memory traces rely on parallel processing. This has been recently demonstrated for human audition. Activation studies in normal subjects and psychophysical investigations in patients with focal hemispheric lesions have shown that auditory information relevant to sound recognition and that relevant to sound localisation are processed in parallel, anatomically distinct cortical networks, often referred to as the “What” and “Where” processing streams. Parallel processing may appear counterintuitive from the point of view of a unified perception of the auditory world, but there are advantages, such as rapidity of processing within a single stream, its adaptability in perceptual learning or facility of multisensory interactions. More generally, implicit learning mechanisms are responsible for the non-conscious acquisition of a great part of our knowledge about the world, using our sensitivity to the rules and regularities structuring our environment. Implicit learning is involved in cognitive development, in the generation of emotional processing and in the acquisition of natural language. Preserved implicit learning abilities have been shown in amnesic patients with paradigms like serial reaction time and artificial grammar learning tasks, confirming that implicit learning mechanisms are not sustained by the cognitive processes and the brain structures that are damaged in amnesia. In a clinical perspective, the assessment of implicit learning abilities in amnesic patients could be critical for building adapted neuropsychological rehabilitation programs.

Musicophilia: tales of music and the brain

Haunted by music. A bolt from the blue : sudden musicophilia ; A strangely familiar feeling : musical seizures ; Fear of music : musicogenic epilepsy ; Music on the brain : imagery and imagination ; Brainworms, sticky music and catchy tunes ; Musical hallucinations -- A range of musicality. Sense and sensibility : a range of musicality ; Things fall apart : amusia and dysharmonia ; Papa blows his nose in G : absolute pitch ; Pitch imperfect : cochlear amusia ; In living stereo : why we have two ears ; Two thousand operas : musical savants ; An auditory world : music and blindness ; The key of clear green : synesthesia and music -- Memory, movement, and music. In the moment : music and amnesia ; Speech and song : aphasia and music therapy ; Accidental davening : dyskinesia and cantillation ; Come together : music and Tourette's Syndrome ; Keeping time : rhythm and movement ; Kinetic melody: Parkinson's disease and music therapy -- Phantom fingers: the case of the one-armed pianist ; Athletes of the small muscles : musician's dystonia -- Emotion, identity, and music. Awake and asleep : musical dreams ; Seduction and indifference ; Lamentations : music and depression ; The case of Harry S. : music and emotion ; Irrepressible : music and the temporal lobes ; A hypermusical species : Williams Syndrome ; Music and identity : dementia and music therapy.

Auditory Localization of Ground-Borne Vibrations in Snakes

Interaural time differences allow many animals to perform azimuthal sound localization. Snakes lack a tympanic membrane, external ear openings, and any other superficial indication of an auditory mechanism. They do, however, possess an inner ear with functional cochlea. The oval window is connected through a loss-free osseous lever system to the two, de facto independent, sides of the lower jaw, which typically rest on the substrate. The footfall of prey generates small-amplitude, low propagation velocity, Rayleigh waves in the soil. This type of wave can be described as fluid motion. Accordingly we apply naval-engineering techniques to show that lower-jaw motion gives rise to a neuronal representation of the auditory world with realistic sensitivity and stereo precision.

Hearing.

The aim of this chapter is to describe some of the features of the processing of the auditory world and how different levels of explanation are appropriate to the understanding of hearing. The working of the inner ear is best seen as a the operation of a purposefully structured machine for the extraction of biologically meaningful components from a sound. Physical scales determine in large part the appropriate description of the auditory system.

Detecting modulated signals in modulated noise: (I) behavioural auditory thresholds in a songbird

Most signals from the auditory world have temporal patterns of amplitude modulation that either emanate from the signal source or result from environmental interference (e.g. air turbulence). To investigate mechanisms associated with the segregation and processing of amplitude-modulated signals, we trained European starlings (Sturnus vulgaris) to detect a signal noise band embedded in several flanking noise bands (FBs). We manipulated the envelope correlation between the signal and FBs, the onset synchrony between signal and FBs (0 or100 ms), signal duration (60 or 400 ms) and the spectrum level of the FBs (15 or 50 dB). The lowest signal-detection thresholds were found when the envelopes of the FBs were correlated with each other but different from the signal envelope (the 'co-uncorrelated' condition). Detection thresholds were on average 7 dB higher when both the signal and the FBs had correlated envelopes (the 'all correlated' condition). Thresholds were even higher when the envelopes of all noise bands were independent (the 'all uncorrelated' condition). The difference in detection thresholds between the co-uncorrelated and the all correlated conditions is termed 'comodulation detection difference' (CDD). Differences in signal duration and masker level had significant effects on detection threshold, but not on CDD magnitudes; differences in onset synchrony had no effects. We compare data from starlings with those from previous psychoacoustic studies of humans, and discuss possible mechanisms on which these perceptual effects may rely. Our behavioural data are the reference for a companion study investigating CDD at the neuronal level of the starling [M.A. Bee et al. (2007) Eur. J. Neurosci., 26, 1979-1994].

The distributed auditory cortex

A synthesis of cat auditory cortex (AC) organization is presented in which the extrinsic and intrinsic connections interact to derive a unified profile of the auditory stream and use it to direct and modify cortical and subcortical information flow. Thus, the thalamocortical input provides essential sensory information about peripheral stimulus events, which AC redirects locally for feature extraction, and then conveys to parallel auditory, multisensory, premotor, limbic, and cognitive centers for further analysis. The corticofugal output influences areas as remote as the pons and the cochlear nucleus, structures whose effects upon AC are entirely indirect, and it has diverse roles in the transmission of information through the medial geniculate body and inferior colliculus. The distributed AC is thus construed as a functional network in which the auditory percept is assembled for subsequent redistribution in sensory, premotor, and cognitive streams contingent on the derived interpretation of the acoustic events. The confluence of auditory and multisensory streams likely precedes cognitive processing of sound. The distributed AC constitutes the largest and arguably the most complete representation of the auditory world. Many facets of this scheme may apply in rodent and primate AC as well. We propose that the distributed auditory cortex contributes to local processing regimes in regions as disparate as the frontal pole and the cochlear nucleus to construct the acoustic percept.

Auditory scene analysis in dyslexics.

It has been argued that dyslexics suffer from temporal sensory processing deficits which affect their ability to discriminate speech in quiet environments. The impact of auditory deficits on non-language aspects of perception, however, is poorly understood. In almost every natural-listening environment, one must constantly construct scenes of the auditory world by grouping and analyzing sounds generated by multiple sources. We investigated whether dyslexics have difficulties grouping sounds. The results demonstrate that dyslexics have an impairment in grouping auditory objects that depends both on the sounds' frequency and presentation rate (i.e. the spectrotemporal context of the sound). We conclude that dyslexics have difficulty constructing scenes of the auditory world, and that these deficits can contribute to learning impairments.

A gain-control mechanism for processing of chorus sounds in the afferent auditory pathway of the bushcricket Tettigonia viridissima (Orthoptera; Tettigoniidae).

The representation of alternative conspecific acoustic signals in the responses of a pair of local interneurons of the bushcricket Tettigonia viridissima was studied with variation in intensity and the direction of sound signals. The results suggest that the auditory world of the bushcricket is rather sharply divided into two azimuthal hemispheres, with signals arriving from any direction within one hemisphere being predominantly represented in the discharge of neurons of this side of the auditory pathway. In addition, each pathway also selects for the most intense of several alternative sounds. A low-intensity signal at 45 dB sound pressure level is quite effective when presented alone, but completely suppressed when given simultaneously with another signal at 60 dB sound pressure level. In a series of intracellular experiments the synaptic nature of the intensity-dependent suppression of competitive signals was investigated in a number of interneurons. The underlying synaptic mechanism is based on a membrane hyperpolarization with a time-constant in the order of 5-10 s. The significance of this mechanism for hearing in choruses, and for the evolution of acoustic signals and signalling behaviour is discussed.

Human complex sound analysis*

The analysis of complex sound features is important for the perception of environmental sounds, speech and music, and may be abnormal in disorders such as specific language impairment in children, and in common adult lesions including stroke and multiple sclerosis. This work addresses the problem of how the human auditory system detects features in complex sound, and uses those features to perceive the auditory world. The work has been carried out using two independent means of testing the same hypotheses; detailed psychophysical studies of neurological patients with central lesions, and functional imaging using positron emission tomography and functional magnetic resonance imaging of normal subjects. The psychophysical and imaging studies have both examined which brain areas are concerned with the analysis of auditory space, and which are concerned with the analysis of timing information in the auditory system. This differs from many previous human auditory studies, which have concentrated on the analysis of sound frequency. The combined lesion and functional imaging approach has demonstrated analysis of the spatial property of sound movement within the right parietal lobe. The timing work has confirmed that the primary auditory cortex is active as a function of the time structure of sound, and therefore not only concerned with frequency representation of sounds.

Human complex sound analysis*

The analysis of complex sound features is important for the perception of environmental sounds, speech and music, and may be abnormal in disorders such as specific language impairment in children, and in common adult lesions including stroke and multiple sclerosis. This work addresses the problem of how the human auditory system detects features in complex sound, and uses those features to perceive the auditory world. The work has been carried out using two independent means of testing the same hypotheses; detailed psychophysical studies of neurological patients with central lesions, and functional imaging using positron emission tomography and functional magnetic resonance imaging of normal subjects. The psychophysical and imaging studies have both examined which brain areas are concerned with the analysis of auditory space, and which are concerned with the analysis of timing information in the auditory system. This differs from many previous human auditory studies, which have concentrated on the analysis of sound frequency. The combined lesion and functional imaging approach has demonstrated analysis of the spatial property of sound movement within the right parietal lobe. The timing work has confirmed that the primary auditory cortex is active as a function of the time structure of sound, and therefore not only concerned with frequency representation of sounds.