Date of Graduation

Spring 2015

Degree

Doctor of Audiology

Department

Communication Sciences and Disorders

Committee Chair

Wafaa Kaf

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.

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

Copyright

© Uzma Shaheen Wilson

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