Assessment of aided ABR thresholds before cochlear implantation.
- 1 October 2000
- journal article
- research article
- Published by Taylor & Francis Ltd in British Journal of Audiology
- Vol. 34 (5), 267-278
- https://doi.org/10.3109/03005364000000138
Abstract
The Nottingham Paediatric Cochlear Implant Programme (NPCIP) specializes in the cochlear implantation of children under the age of 5 years. The initial stage in the pre-implant evaluation process is audiological assessment. In complex paediatric cases, behavioural audiological assessment may be difficult. In such cases, an objective measure to verify the aided hearing threshold is desirable. This study compares unaided and aided hearing thresholds, by both objective and behavioural techniques, in 20 children (aged <1-10 years). Objective data were collected from auditory brainstem responses (ABR) and behavioural thresholds were measured by use of developmental age-appropriate tests. When comparing the unaided ABR click threshold to the behavioural threshold (obtained from the average of 1-4 kHz warble tones) the ABR threshold was, on average, 9 dB lower (more sensitive). Using the same comparison for aided responses a difference of <5 dB was observed. Unaided ABR thresholds resulted in 35% of subjects responding to the click stimulation (when using a maximum stimulation level of 105 dB nHL), whereas introducing aided ABR measurement elicited positive results in 75% of subjects. The effect of the hearing aid on the stimulus was measured by use of a 2 cc coupler which was connected to a precision sound level meter, whose AC output was recorded onto digital audiotape. Analysis of the resultant output spectra in the frequency domain highlighted signal non-linearity and distortion when using high-intensity stimuli with moderate to high aid gains. In conclusion, aided ABR thresholds are valuable in the management of young children. However, when performing either ABR or behavioural aided hearing threshold measurements it is essential to be aware of the limitations of the hearing aid and the stimulus.Keywords
This publication has 12 references indexed in Scilit:
- Estimation of the pure-tone audiogram by the auditory brainstem response: a review.Audiology and Neurotology, 1997
- Electric Response Audiometry in Young Children Before Cochlear Implantation: A Short Latency ComponentEar & Hearing, 1996
- Tympanometry, Stapedius Reflex and Hearing Impairment in Children with Otitis Media with EffusionActa Oto-Laryngologica, 1994
- Preliminary Studies on the Use of an ABR Amplitude Projection Procedure for Hearing Aid SelectionEar & Hearing, 1990
- The IHR-McCormick Automated Toy Discrimination test—description and initial evaluationBritish Journal of Audiology, 1989
- Comparison of Onset and Steady-State Responses of Hearing AidsJournal of Speech, Language, and Hearing Research, 1987
- Application of ABRS to the Hearing-Aid Selection ProcessJournal of Speech, Language, and Hearing Research, 1986
- Role of Auditory Brain Stem Response in the Selection of Hearing AidsEar & Hearing, 1983
- Hearing Aid Selection by Brainstem AudiometryScandinavian Audiology, 1982
- Recommended Procedures for Pure-tone Audiometry Using a Manually Operated InstrumentBritish Journal of Audiology, 1981