Date of Graduation

Spring 2015

Degree

Doctor of Audiology

Department

Communication Sciences and Disorders

Committee Chair

Wafaa Kaf

Keywords

auditory steady-state response, auditory brainstem response, Kalman-weighted filtering, hearing assessment in children, low-frequency hearing loss

Subject Categories

Speech Pathology and Audiology

Abstract

Auditory brainstem responses (ABR) and auditory steady state responses (ASSR) are useful for estimating hearing in difficult-to-test populations. For these populations, Kalman-weighted filtering and in-situ pre-amplification can be advantageous for ABR recordings, but little is known about the accuracy of 40-Hz sinusoidal ASSR (sASSR) thresholds using these techniques. The primary aims of this study were to determine the accuracy of: a) 40-Hz sASSR thresholds compared to both toneburst-ABR and behavioral thresholds; and b) automated ASSR (aASSR) in a semi-alert population. Behavioral and electrophysiological thresholds for 500, 2000 and 4000 Hz TB and narrow-band chirp stimuli were obtained using both 2000 and 4000 equivalent sweeps. With 4000 sweeps, significantly better thresholds were obtained for sASSR than TB-ABR for 500 Hz only. With 2000 sweeps, significantly better thresholds were obtained for TB-ABR than for sASSR for 4000 Hz only. 4000 sweep findings demonstrate that 40-Hz sASSR is useful for estimating low-frequency hearing with adequate averaging, whereas 2000 sweep findings suggest sASSR thresholds may be dependent upon response averaging. Multi-frequency screening of aASSR yielded a 61% passing rate using a 20 dB HL stopping level. These findings have clinical applications: a) 40-Hz sASSR may be helpful for low frequency thresholds; b) 40-Hz aASSR multi-frequency screening may be useful, although thresholds should be normed to behavioral thresholds for best results.

Copyright

© Uzma Shaheen Wilson

Campus Only

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