Download or read book Psychophysical Study of Central Auditory Processing with Peripheral and Neural Deficits written by Carol Q. Pham and published by . This book was released on 2016 with total page 139 pages. Available in PDF, EPUB and Kindle. Book excerpt: The present dissertation includes three studies collectively investigating perceptual consequences of peripheral and neural deficits in central auditory processes occurring in the ascending pathway from cochlea to cortex. Chapter 1 describes a study of how electrical stimulation delivered from a cochlear implant affects processing of co-varying frequency (spectral-variance) and temporal cues. We hypothesized post-lingually deaf cochlear implant listeners retain central processing abilities, which are hampered by degraded peripheral, cochlear inputs. In eight cochlear implant listeners, we measured auditory nerve compound action potentials to estimate peripheral filters, quantifying implant-induced spread of current and resultant spread of neural excitation. Then, we measured psychophysical detection thresholds in the presence of multi-electrode maskers placed either inside or outside the peripheral filter to determine peripheral and central contributions on processing. Results from actual and simulated implant listening support the hypothesis broad peripheral filters greatly limit central processing of spectral-variance, but not of temporal cues. Chapter 2 reports four experiments investigating effects of nicotine (6 mg) gum on auditory tasks with varying attentional demand in healthy, normal hearing subjects. Lack of drug effects on central gain (tone-in-noise detection), temporal acuity (auditory gap detection), frequency resolution (spectral ripple discrimination), or auditory discrimination (attended listening) seem largely due to ceiling performance. Variability in the most demanding gap condition just reaching a significant decrease with nicotine could reflect improved temporal summation. Presumably, low task demand and maximum individual baseline attentional processing limit nicotine effects. Correlation analyses propose separability of attention and auditory processes and dissociable gap detection mechanisms. Chapter 3 describes a study in auditory neuropathy--- disorders typically disrupting synaptic encoding and/or neural transmission of auditory signals in the cochlea and auditory nerve-- differentiating temporal gap processes. The data seemingly support our hypothesis desynchronized neural discharges and/or reduced neural input limit peripheral temporal acuity but not central temporal acuity. Comparing subjects with disrupted auditory nerve activity with control subjects, a significant gap delay on the order of tens of milliseconds and insignificant delay on the order of hundreds of milliseconds may differentiate peripherally- and centrally-based temporal processing, respectively. We conclude by summarizing results and exploring future research for medical interventions.

Download or read book The Aging Auditory System written by Sandra Gordon-Salant and published by Springer Science & Business Media. This book was released on 2009-12-02 with total page 311 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume brings together noted scientists who study presbycusis from the perspective of complementary disciplines, for a review of the current state of knowledge on the aging auditory system. Age-related hearing loss (ARHL) is one of the top three most common chronic health conditions affecting individuals aged 65 years and older. The high prevalence of age-related hearing loss compels audiologists, otolaryngologists, and auditory neuroscientists alike to understand the neural, genetic and molecular mechanisms underlying this disorder. A comprehensive understanding of these factors is needed so that effective prevention, intervention, and rehabilitative strategies can be developed to ameliorate the myriad of behavioral manifestations.

Download or read book Central Auditory Processing and Neural Modeling written by Paul F. Poon and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 507 pages. Available in PDF, EPUB and Kindle. Book excerpt: The full power of combining experiment and theory has yet to be unleashed on studies of the neural mechanisms in the brain involved in acoustic information processing. In recent years, enormous amounts of physiological data have been generated in many laboratories around the world, characterizing electrical responses of neurons to a wide array of acoustic stimuli at all levels of the auditory neuroaxis. Modern approaches of cellular and molecular biology are leading to new understandings of synaptic transmission of acoustic information, while application of modern neuro-anatomical methods is giving us a fairly comprehensive view ofthe bewildering complexity of neural circuitry within and between the major nuclei of the central auditory pathways. Although there is still the need to gather more data at all levels of organization, a ma jor challenge in auditory neuroscience is to develop new frameworks within which existing and future data can be incorporated and unified, and which will guide future laboratory ex perimentation. Here the field can benefit greatly from neural modeling, which in the central auditory system is still in its infancy. Indeed, such an approach is essential if we are to address questions related to perception of complex sounds including human speech, to the many di mensions of spatial hearing, and to the mechanisms that underlie complex acoustico-motor behaviors.

Download or read book Central Auditory Processing written by Jack Katz and published by . This book was released on 1992 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Disorders of Peripheral and Central Auditory Processing written by Gastone G. Celesia and published by Elsevier Health Sciences. This book was released on 2013-12-12 with total page 491 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Age related Changes in Auditory Temporal Processing written by Jacqueline Alexandra Overton and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Age-related hearing loss (ARHL) is the third most prevalent cause of disability in adults over age 65. However, we still do not have an adequate understanding of the mechanisms underlying ARHL. The primary complaint of those with ARHL is a difficulty comprehending speech, particularly in challenging listening environments. This can lead to social isolation, depression and contribute to cognitive decline. Importantly, impairments in speech processing and comprehension occur even in the absence of measurable changes in hearing thresholds. Similarly, speech comprehension difficulties are often not corrected with hearing aids. Understanding age-related changes in temporal processing in the central auditory system is critical to understanding the neural mechanisms of speech processing deficits associated with ARHL. This is the central question of my thesis.There are five chapters in this dissertation. In Chapter 1, I introduce the thesis with an overview of ARHL, and a review of the literature covering age related changes in speech and temporal processing, and age-related changes in the central auditory pathway. In Chapter 2, I present single-unit electrophysiology data recorded from primary auditory cortex (A1) in older rhesus macaque monkeys in response to amplitude modulated (AM) broadband noise presented across a range of modulation frequencies, and compare those data with the results from younger monkeys reported previously in Yin and colleagues (2011). This was the first study of age-related changes in cortical auditory temporal processing in the macaque. I found that neurons from older monkeys show dramatic changes in their responses to AM noise as measured by their ability to phase-lock to the envelope and by their overall firing rate. Several measures of tuning were correlated in young monkeys, but these relationships were either reversed, or lost in units from older monkeys. Underlying these changes was a decrease in the ability of older neurons to phase-lock to the envelope of an AM stimulus, and dramatically increased spontaneous and evoked firing rates (replicated from previous studies). These data, however, were collected under passive stimulus presentation conditions, so it is unclear how these changes affect the ability to accurately represent the stimulus. The logical follow-up to the study presented in Chapter 2, is to record from single units in macaque A1 while they are performing a task that requires them to attend to and make decisions regarding a specific attribute of the AM stimulus (in this case modulation frequency). I, therefore, designed a two-alternative forced choice (2AFC) AM frequency discrimination task for this purpose. How modulation frequency discrimination ability may change with age had not been tested previously. Hence, in Chapter 3, I present psychophysical data from a cross-sectional sample of 33 human participants ranging in age from 25 to 80 years, and compare those data to results from one 16-year old macaque. I found an age-related decline in AM frequency discrimination at the highest AM frequencies measured, but no age-related difference in performance at lower frequencies. Importantly, age-related changes in discrimination ability were not related to hearing thresholds, further supporting that age-related temporal processing deficits are due to changes in the central auditory system independent of peripheral changes. Comparison to monkey data showed that human subjects’ discrimination ability was more acute overall, and extended to temporal frequencies beyond the monkey’s upper limit of AM frequency discrimination. This result suggests a perceptual specialization in humans for fine changes in temporal frequency that is likely to be relevant to speech processing. This section of the thesis is concluded in Chapter 4, where I discuss the implications of results presented in the previous two chapters in the context of the introductory chapter, and offer directions for future research. Cranial implants are a necessary component of neurophysiological investigation of nonhuman primates. In Chapter 5, I present a methodology for implanting nonhuman primates with custom-fitted acrylic-free headposts and recording cylinders using biocompatible materials. Each titanium headpost was hand-form to fit a 3D-printed replica of the animal’s skull, which was created from CT data. I provide a timeline and detail each step of the process, including information for converting DICOM data to a 3D-printable format. Furthermore, I discuss issues of biocompatibility of materials, and suggest procedures for promoting osseointegration of titanium implants. Overall, these methods have proven to reduce implant surgery times up to 70%. All implanted headposts remained intact and free of infection for the experimental life of each animal (four years and counting).

Download or read book Peripheral and Central Auditory Processing in People With Absolute Pitch written by Larissa A. Mcketton and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Absolute pitch (AP) is a rare ability that is defined by being able to name musical pitches without a reference standard. This ability has been of interest to researchers studying music cognition and the processing of pitch information because it is very rarely expressed and raises questions about developmental interactions between biological predispositions and musical training. This dissertation focuses mainly on the peripheral and central neural substrates and is divided into seven chapters. The first chapter reviews the anatomy, function, and frequency resolution of the auditory peripheral and central nervous system. It includes background information pertaining to the origins of AP and describes inconsistencies reported throughout a number of studies that characterize AP emergence. Chapter two details a series of peripheral experiments on twenty AP and thirty-three control subjects recruited for testing at two locations. The goal was to test whether frequency resolution differences could be resolved at the level of the cochlea within both groups as a potential correlate for the genesis of AP. Chapter three details two behavioural tests that were administered to assess the smallest frequency difference that AP musicians could resolve and to test how well they could detect melodic mistuning excerpts compared to non-AP musicians and controls without musical experience. Both AP musicians and non-AP musicians did significantly better in both tests compared to non-musicians. However, there were no differences between the AP and non-AP musician groups. Chapter four details a functional MRI study that measured frequency tuning in the cortex using a population receptive field (pRF) model that estimates preferred frequency bandwidth in each voxel. This method was also tested in auditory subcortical nuclei such as the inferior colliculus and medial geniculate nucleus. Chapter five reports the neuro-anatomical correlates of musicianship and AP using structural MRI. Here we investigated cortical thickness and volume differences among the three groups and found a number of regions differed significantly. Cortical thickness was significantly greater in the left Heschls gyrus (an area that acts as a central hub for auditory processing) in AP musicians compared to non-AP musicians and non-musicians. AP and non-AP musicians also exhibited increased cortical thickness and volume throughout their cortex and subcortex. In line with previous studies, AP musicians showed decreased cortical thickness and volume in frontal regions such as the pars opercularis part of the inferior frontal gyrus. Chapter six reports the neuro-anatomical correlates of musicianship and AP using diffusion tensor imaging (DTI) to measure connectivity and white matter structural integrity in regions associated with audition and language processing. Tracts connecting language processing regions were reduced in volume in AP musicians compared to their non-AP counterparts. Chapter seven includes the general discussion, which integrates the findings and results from the five experiments. Our findings indicate that the sharpness of frequency tuning did not differ in either peripheral or central auditory processing stages among AP and non-AP groups. This implies that AP possessors do not encode or represent auditory frequency any differently than other groups, from the periphery through auditory cortex; instead, the neural substrate of their abilities must lie elsewhere. The automatic and working memory independent categorization abilities in AP may reflect more refined efficiency in local but not global functional connectivity.

Download or read book Research Awards Index written by and published by . This book was released on 1987 with total page 826 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Auditory Brain and Age Related Hearing Impairment written by Jos J. Eggermont and published by Academic Press. This book was released on 2019-01-09 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Auditory Brain and Age-Related Hearing Impairment provides an overview of the interaction between age-related hearing impairments and cognitive brain function. This monograph elucidates the techniques used in the connectome and other brain-network studies based on electrophysiological methods. Discussions of the manifestations of age-related hearing impairment, the causes of degradation of sound processing, compensatory changes in the human brain, and rehabilitation and intervention are included. There is currently a surge in content on aging and hearing loss, the benefits of hearing aids and implants, and the correlation between hearing loss, cognitive decline and early onset of dementia. Given the changing demographics, treatment of age-related hearing impairment need not just be bottom-up (i.e., by amplification and/or cochlear implantation), but also top-down by addressing the impact of the changing brain on communication. The role of age-related capacity for audio-visual integration and its role in assisting treatment have only recently been investigated, thus this area needs more attention.

Download or read book Biomedical Index to PHS supported Research pt A Subject access A H written by and published by . This book was released on 1992 with total page 1192 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Research Grants Index written by National Institutes of Health (U.S.). Division of Research Grants and published by . This book was released on 1973 with total page 1130 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Aging and the Auditory System written by James Willot and published by . This book was released on 1991-12-17 with total page 300 pages. Available in PDF, EPUB and Kindle. Book excerpt: This text considers the effects of ageing on the auditory system from an anatomical, physiological and psychophysical perspective. Amongst the areas covered are ageing and the outer middle ear and the etiology of inner ear pathology and its relationship to presbycusis

Download or read book Biomedical Index to PHS supported Research written by and published by . This book was released on 1990 with total page 1060 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book New Advances in Electrocochleography for Clinical and Basic Investigation written by Jeffery T. Lichtenhan and published by Frontiers Media SA. This book was released on 2018-07-09 with total page 315 pages. Available in PDF, EPUB and Kindle. Book excerpt: Electrocochleography (ECochG) is an approach for objective measurements of physiologic responses from the inner ear. Measurements have classically been made from electrodes placed in the outer ear canal, on the tympanic membrane, the round window niche, or inside the cochlea. Recent innovations have led to ECochG being used for exciting new purposes that drive clinical practice and contribute to the basic understanding of inner ear physiology. Cochlear implant recording electrodes can monitor the preservation of residual, low-frequency acoustic hearing, both in the operating room and post-operatively. ECochG measurements can quantify differential effects of inner ear surgery or other manipulations on vestibular and auditory physiology simultaneously. Various attributes of cognitive neuroscience can be addressed with ECochG measurements from the auditory periphery. These advances in ECochG provide a way to understand a variety of inner ear diseases and are likely to be of value to many groups in their own clinical and basic research.

Download or read book Noise and the Brain written by Jos J. Eggermont and published by Academic Press. This book was released on 2013-09-12 with total page 393 pages. Available in PDF, EPUB and Kindle. Book excerpt: In our industrialized world, we are surrounded by occupational, recreational, and environmental noise. Very loud noise damages the inner-ear receptors and results in hearing loss, subsequent problems with communication in the presence of background noise, and, potentially, social isolation. There is much less public knowledge about the noise exposure that produces only temporary hearing loss but that in the long term results in hearing problems due to the damage of high-threshold auditory nerve fibers. Early exposures of this kind, such as in neonatal intensive care units, manifest themselves at a later age, sometimes as hearing loss but more often as an auditory processing disorder. There is even less awareness about changes in the auditory brain caused by repetitive daily exposure to the same type of low-level occupational or musical sound. This low-level, but continuous, environmental noise exposure is well known to affect speech understanding, produce non-auditory problems ranging from annoyance and depression to hypertension, and to cause cognitive difficulties. Additionally, internal noise, such as tinnitus, has effects on the brain similar to low-level external noise.Noise and the Brain discusses and provides a synthesis of hte underlying brain mechanisms as well as potential ways to prvent or alleviate these aberrant brain changes caused by noise exposure. - Authored by one of the preeminent leaders in the field of hearing research - Emphasizes direct and indirect changes in brain function as a result of noise exposure - Provides a comprehensive and evidence-based approach - Addresses both developmental and adult plasticity - Includes coverage of epidemiology, etiology, and genetics of hearing problems; effects of non-damaging sound on both the developing and adult brain; non-auditory effects of noise; noise and the aging brain; and more

Download or read book Journal of Rehabilitation R D written by and published by . This book was released on 2005 with total page 758 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Diagnosis and Treatment of Vestibular Disorders written by Seilesh Babu and published by Springer. This book was released on 2019-01-24 with total page 390 pages. Available in PDF, EPUB and Kindle. Book excerpt: This text reviews the current understanding of vestibular anatomy allowing for a framework of reference, and how it's applied to vestibular testing, diagnosis and management of dizziness. Vestibular testing is an important tool in the evaluation and management of the patient with dizziness. It aids in establishing a diagnosis and determining the side or site of the lesion. In addition, it guides practitioners in selection of treatment and allows the ability of the patient’s condition to be evaluated over its time course. Common vestibular pathologies such as benign positional vertigo, Meniere’s disease, multisensory imbalance, vestibular neuritis, superior canal dehiscence, and vestibular migraine will be addressed in a concise and understandable manner. The text follows a clear format in which the etiology, pathophysiology, diagnostic features and medical or surgical management of such pathologies are discussed. The book gains increased importance as superior canal dehiscence and vestibular migraine are relatively new hot topics. Lastly, relatively rare entities such as bilateral vestibular hypofunction, pediatric vestibular disorders and central vestibular disorders are discussed. This text serves as a complete reference for clinicians, students and researchers interested in this common and severe disorder allowing for improved patient care and advancement of knowledge in the field. Chapters are written by acknowledged experts, allowing summary review of the newest and most up-to-date understanding of scientific information. Diagnosis and Treatment of Vestibular Disorders will be an invaluable resource for otolaryngologists, neurologists, otologists and neurotologists, basic science and translational researchers with interests in the vestibular system, fellows and residents in aforementioned fields, and general practitioners with an interest in patients with symptoms of dizziness.