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Development Of An Intervention For Improving Food Acceptance Of People With Hearing Loss, Sara Esther Jarma Arroyo

Graduate Theses and Dissertations

Hearing loss, defined as the partial or total inability to hear sound in one or both ears, is the most common sensory deficit in adults to date. Approximately 15% of American adults aged 18 and over report some trouble hearing. The impact of hearing loss may be profound, with consequences for the social, functional, and psychological well-being of the person. Surprisingly, very little attention has been paid on whether auditory loss can significantly impact consumers’ sensory perception and overall enjoyment of food. There were four objectives of this dissertation study. Chapter 1 aimed to determine the impacts of hearing loss …

Uncovering Deficits In Auditory Processing And Cognition Following Hearing Loss And Prefrontal Cortex Dysfunction, Krystyna B. Wieczerzak

Electronic Thesis and Dissertation Repository

How the auditory cortex and higher-order cortical regions, e.g., the prefrontal cortex, interact for accurate auditory processing and perception is not fully understood. Furthermore, although hearing loss is correlated with cognitive impairment, and animal studies have shown that loud noise exposure causes hippocampal neuropathology, the effects of noise-induced hearing loss on the medial prefrontal cortex (mPFC) and higher-level cognitive functions have not been well studied. Using electrophysiological and cognitive-behavioural testing in rats, Chapter 2 provides the first evidence of noise-induced plasticity in the mPFC (e.g., loss of functional connectivity with the auditory cortex) and deficits in stimulus-response habit learning. Although …

Cognitive Resources Are Recruited Consistently Across People During Story Listening, Matthew T. Bain

Electronic Thesis and Dissertation Repository

Degraded speech encoding as a result of hearing loss increases cognitive load and makes listening effortful. Standard hearing assessment does not capture this cognitive impact of hearing impairment. Speech-in-noise testing measures intelligibility for isolated sentences that are typically not engaging and lack meaningful context. These materials may not capture the processes involved in everyday listening situations, in which people are often intrinsically motivated to comprehend the speech they are hearing. The current study explored a novel approach using natural, spoken stories. We first characterized time courses of executive load during story listening in young individuals with normal hearing using a …

Elevated Cochlear Adenosine Causes Hearing Loss Via Adora2b Signaling, Jeanne Manalo

Dissertations & Theses (Open Access)

Over 538 million people in the world have been diagnosed with hearing loss (HL). Current treatments for the most common type of HL, sensorineural HL, are limited to hearing aids and cochlear implants with no FDA-drugs available. The hearing process demands an abundance of ATP and HL is often attributed to a disruption in this metabolic energy currency. Patients who lack adenosine deaminase (ADA), the enzyme that irreversibly metabolizes adenosine, have high levels of adenosine that yield severe health problems, including HL; however, the pathogenic mechanisms behind HL and adenosine remain elusive. Our lab has found a HL phenotype in …

Advanced Phenotyping Of Otosclerosis In An Ontario Population And Two Large Newfoundland Families, Matthew B. Lucas

Electronic Thesis and Dissertation Repository

Otosclerosis is a relatively common hearing loss disorder characterized by abnormal bone growth in the otic capsule leading to stapes fixation. In approximately half of cases, otosclerosis is inherited as an autosomal dominant trait. Typically, gene discovery efforts rely on surgical confirmation, audiometry and occasionally acoustic reflexes to identify affected cases of otosclerosis within families, requiring that the otosclerosis was at an advanced stage to be detected. This makes it difficult to identify individuals with early otosclerosis. The use of advanced phenotyping to identify cases of otosclerosis was tested in an Ontario otosclerotic population as well as in two large …

Investigating The Relationship Between Subcortical And Cortical Auditory Processing, Sonia Varma

Electronic Thesis and Dissertation Repository

The auditory system is highly integrative, with feedforward and feedback connections from periphery to cortex (and stages in between). In order to understand how the different levels of the human auditory system interact, it is necessary to simultaneously measure responses from multiple auditory levels. A novel stimulus was paired with electroencephalography (EEG) in 29 young, normal-hearing participants (17-34 years) to examine interactions among stages of the auditory pathway. Temporal regularity was manipulated by continuously accelerating and decelerating the rate of a click-train stimulus (i.e., ~3.5 Hz frequency modulation of the click rate). Adaptation of the brainstem (cochlear nucleus and inferior …

Cortical Plasticity Following Adult-Onset Hearing Loss, Ashley L. Schormans

Electronic Thesis and Dissertation Repository

The consequences of hearing loss are not confined to how the central auditory system processes sound; crossmodal plasticity also occurs, which is characterized by an increased responsiveness of neurons in auditory areas to visual and/or tactile stimuli. In the primary auditory cortex, partial hearing loss causes a decrease in the number of auditory-responsive neurons, as well as an increase in multisensory neurons. However, it was relatively unknown how adult-onset hearing loss affected cortical areas that are already capable of integrating multisensory information, such as the lateral extrastriate visual cortex (V2L). Using a combination of in vivo electrophysiology, neuropharmacology and behavioural …

Accessing Resources: The Narratives Of Women Working With A Hearing Loss, Ashley Martindale

Electronic Thesis and Dissertation Repository

This narrative study describes the stories of women who are experiencing a hearing loss while working. It seeks to understand why these women may or may not be accessing resources. A narrative approach was used in order to gain in-depth description of the experiences of the participants. Two one-on-one interviews were completed with each of the eight participants.

After analysis of the interviews, five themes emerged. These themes included degree of hearing loss and communication demands, childhood experiences, financial factors, knowledge and awareness of others, and workplace environments. Insights of this “invisible” disability as well as ways in which women …

Molecular And Pathological Analyses Of Three New Mouse Mutations That Affect Ear Development And Function, Cong Tian

Electronic Theses and Dissertations

This dissertation presents three new mouse models that help to study the functions of Enpp1, Atp6v1b1, and Tbx1 for ear development and function. asj (aging with stiffened joints) carries a missense mutation in the mouse Enpp1 gene. Enpp1 encodes the enzyme ENPP1 that regulate soft-tissue calcification and bone mineralization, and is associated with generalized arterial calcification of infancy and hypophosphatemic rickets in human patients. asj mutant mice show severe middle ear infection and tissue calcification, which provide a new mouse model to study otitis media and tympanoscleorosis. Atp6v1b1 encode a protein that is a subunit of the V-ATPase …

An Evaluation Of An Auditory Neurophysiological Model, Alysha Nicole Waters

Undergraduate Honors Capstone Projects

Individuals with normal hearing are adept at understanding speech in the presence of noise, such as other speakers or environmental sounds. In contrast, individuals with hearing loss struggle to understand speech in the same adverse conditions. Neural processing in the inferior colliculus (IC) of the brainstem appears to contribute to the ability to separate simultaneous competing sounds. A computational model developed in the Sinex lab reproduces the responses of IC neurons to complex sound mixtures. It seems likely that the model can be applied to improve the processing of speech in noise. The computational model's effectiveness at improving the processing …