Biomedical subjects

DeWet Swanepoel

Publications and source records attributed to DeWet Swanepoel.

3 recordsLinked to original sources

PubMed2005

Predicting pure-tone thresholds with dichotic multiple frequency auditory steady state responses.

The accuracy of dichotic multiple frequency auditory steady state in predicting pure-tone thresholds at 0.5, 1, 2, and 4.0 kHz compared to an ABR protocol (click and tone burst at 0.5 kHz) were explored in a group of 25 hearing-impaired subjects across the degree and configuration spectrum. Mean steady state thresholds were within 14, 18, 15, and 14 dB of the pure tones at 0.5, 1, 2, and 4 kHz, compared to the tone-burst ABR at 0.5 kHz pure-tone difference of 24 dB, and a click-evoked pure-tone (2-4 kHz) difference of 9 dB. Recording time for the steady state protocol was 28 minutes (+/- 11) compared to 24 minutes (+/- 9) of the ABR protocol. Degree of loss had a significant effect on steady state; configuration of hearing loss had a limited effect. Mf ASSR predicted thresholds with relative accuracy although some configurations showed discrepancies for low-frequency estimates.

Acoustic Stimulation↗

PubMed2004

Auditory steady-state responses for children with severe to profound hearing loss.

OBJECTIVE: To investigate the clinical usefulness of the dichotic single-frequency auditory steady-state response (ASSR) for estimation of behavioral thresholds in children with severe to profound congenital sensorineural hearing loss. DESIGN: A comparative experimental research design was selected to compare behavioral and ASSR thresholds for the sample. Behavioral pure-tone audiometry served as the criterion standard. SETTING: Hearing Clinic, Department of Communication Pathology, University of Pretoria, Pretoria, South Africa. PATIENTS: A referred sample of 10 patients (20 ears), 5 girls and 5 boys aged 10 to 15 years (mean age, 13 years 4 months), with severe to profound sensorineural hearing impairment. MAIN OUTCOME MEASURES: The difference, and correlation, between 160 pure-tone behavioral and ASSR thresholds at 0.5, 1, 2, and 4 kHz. RESULTS: Mean differences between ASSR and behavioral thresholds were 6 dB for 0.5 kHz and 4 dB for 1, 2, and 4 kHz, with standard deviations varying between 8 and 12 dB. No significant differences (P<.05) were observed between ASSR and behavioral thresholds, except at 0.5 kHz, and Pearson correlation coefficients varied between 0.58 and 0.74 across the evaluated frequencies, with best correlation at 1 kHz and worst at 0.5 kHz. CONCLUSIONS: The ASSR thresholds provided reliable estimations of behavioral thresholds for children with severe to profound hearing loss and indicated an increased sensitivity for more profound hearing loss.

Adolescent↗

PubMedDate not supplied

Estimations of auditory sensitivity for young cochlear implant candidates using the ASSR: preliminary results.

This paper presents preliminary results obtained with the use of the auditory steady-state response (ASSR) technique as part of a cochlear implant candidacy assessment protocol for infants Fifteen infants (30 ears), between 10 and 60 months of age, with severe-to-profound hearing loss participated in the study. ASSR measurements were performed for 0.5, 1, 2 and 4kHz at intensities up to 120-128dB HL. The ASSR thresholds were obtained in 74%, of the measurements, and exceeded the maximum auditory brainstem response (ABR) intensity output in 91% of cases and the maximum free-field behavioral intensity output in 84% of cases. Eighty-seven per cent of ASSR threshold measurements were measured at intensities of 100dB HL or higher, and almost half (47%) were measured at intensities of 115 dB HL and higher. Preliminary results indicate that absent ABR and behavioral thresholds do not preclude the possibility of residual hearing, making the ASSR a primary source of information regarding profound levels of hearing loss.

Auditory Perception↗