Publications by authors named "D Dundas"

Objective: The Earlens is a direct-drive hearing device consisting of a lens which physically displaces the umbo to achieve appropriate gain. The objective is to determine the clinical acceptability of clinical immittance measurements in Earlens wearers.

Design: Controlled before-after within-subjects repeated measures study.

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Direct drive hearing devices, which deliver a signal directly to the middle ear by vibrating the tympanic membrane via a lens placed in contact with the umbo, are designed to provide an extension of audible bandwidth, but there are few studies of the effects of these devices on preference, speech intelligibility, and loudness. The current study is the first to compare aided speech understanding between narrow and extended bandwidth conditions for listeners with hearing loss while fitted with a direct drive hearing aid system. The study also explored the effect of bandwidth on loudness perception and investigated subjective preference for bandwidth.

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Objective: To determine sound quality for extended bandwidth amplification using a direct drive hearing device.

Study Design: Prospective double-blind within-subjects repeated measures study.

Setting: University hearing research laboratories.

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Objectives: The objective of this study was to test the ability to achieve, maintain, and subjectively benefit from extended high-frequency amplification in a real-world use scenario, with a device that restores audibility for frequencies up to 10 kHz.

Design: A total of 78 participants (149 ears) with mild to moderately-severe sensorineural hearing loss completed one of two studies conducted across eight clinical sites. Participants were fitted with a light-driven contact hearing aid (the Earlens system) that directly drives the tympanic membrane, allowing extended high-frequency output and amplification with minimal acoustic feedback.

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Ionization of acetylene by linearly-polarized, vacuum ultraviolet (VUV) laser pulses is modelled using time-dependent density functional theory. Several laser wavelengths are considered including one that produces direct ionization to the first excited cationic state while another excites the molecules to a Rydberg series incorporating an autoionizing state. We show that for the wavelengths and intensities considered, ionization is greatest whenever the molecule is aligned along the laser polarization direction.

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