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Behavioural And Objective Assessment Of Binaural Hearing In Adult Listeners With Acquired Unilateral Conductive Hearing Loss Before And After Middle Ear Surgery, Parvaneh Abbasalipour

Electronic Thesis and Dissertation Repository

In normally hearing listeners, binaural hearing relies on symmetrical input from the two ears. Previous studies on human listeners have assessed the effect of induced unilateral conductive hearing loss (UCHL) during adulthood via earplugging. These experiments indicated initial difficulty in sound localization followed by gradual improvement due to adaptation to the perturbed binaural cues. The limited duration of earplug use does not represent the consequences of chronic UCHL secondary to disease. Furthermore, there is insufficient information regarding the adaptation of binaural hearing abilities after treatment of late-onset UCHL.

The current study assessed the binaural hearing abilities of adult listeners with …

Identification Of The Smallest Perceivable Interaural Time Differences, Sinthiya Thavam

Electronic Thesis and Dissertation Repository

Several studies have reported human threshold interaural time differences (ITDs) near 10 μs; however, none of these studies aimed to find the stimulus and experimental method that yields the lowest threshold. The goal of the current study is to systematically determine the stimulus and the experimental paradigm that yields the smallest threshold ITD and to provide an accurate reference value. We systematically varied seven parameters: stimulus waveform, stimulus level, stimulus duration, adaptive versus constant stimulus procedure, number of reference intervals, inter-stimulus pause duration, and inclusion versus exclusion of onset and offset ITD. The condition yielding the lowest threshold ITD was …

Role Of The Cochlea And Efferent System In Children With Auditory Processing Disorder, Sriram Boothalingam

Electronic Thesis and Dissertation Repository

Auditory processing disorder (APD) is characterized by difficulty listening in noisy environments despite normal hearing thresholds. APD was previously thought to be restricted to deficits in the central auditory system. The current work sought to investigate brainstem and peripheral mechanisms that may contribute to difficulties in speech understanding in noise in children with suspected APD (sAPD). Three mechanisms in particular were investigated: cochlear tuning, efferent function, and spatial hearing. Cochlear tuning was measured using stimulus frequency otoacoustic emission (SFOAE) group delay. Results indicate that children suspected with APD have atypically sharp cochlear tuning, and reduced medial olivocochlear (MOC) functioning. Sharper-than-typical …

The Effects Of Target Spectrum, Noise, And Reverberation On Auditory Cue Weighting In Sound Localization, Tran M. Nguyen

Electronic Thesis and Dissertation Repository

Sound localization in the horizontal plane depends on interaural time difference (ITD) and interaural level difference (ILD) cues, which are both available in wideband sounds. Previous studies have directly measured listener weighting of those cues only under quiet, anechoic conditions, but not in the presence of noise and reverberation, which can degrade both ITD and ILD. This study examined the effects of changes in target spectral profile, background noise, and reverberation on sound localization performance and cue weighting strategies. Listeners reported locations of targets that were presented over headphones in virtual auditory space. ITD and ILD were manipulated by attenuating …