Veronica Smyth

Effects of background noise on click-evoked otoacoustic emissions.

Objective: To investigate the effect of increased levels of background noise on click‐evoked otoacoustic emission (CEOAE) recordings and to compare the effectiveness of the default CEOAE program with the QuickScreen CEOAE program in increased levels of noise, using an Otodynamics ILO88 recording device. Design: The right ears of 40 young adult women with normal hearing were assessed using CEOAEs under four different noise conditions and with two different methods of data collection. The noise conditions were in quiet, 50 dB A, 55 dB A, and 60 dB A of white noise. Data were collected at each noise level in the default mode and also using the ILO88 QuickScreen program. Results: There was a significant change in a number of important CEOAE output parameters with increased noise. In the default mode, mean whole wave reproducibility was 89.2% in quiet but declined to 85% with 50 dB A of white noise, 65% at 55 dB A and 20% at 60 dB A. The QuickScreen program proved more robust to the effects of noise than the default. In that mode, mean whole wave reproducibility was 91.7% in quiet, 92.5% with 50 dB A of white noise, 82.5% at 55 dB A and 45% at 60 dB A. Conclusions: The findings of the study indicate ambient noise levels for accurate CEOAE recording should not exceed 50 to 55 dB A of noise and alternatives to the default program should be considered in non‐sound‐treated situations.

Otoacoustic emission criteria for neonatal hearing screening

Transient evoked otoacoustic emission measures are gaining acceptance as a technique in new-born hearing screening. At present a wide variety of pass-fail screening criteria are used in otoacoustic emission screening programs. In a study of 100 special care neonates and 35 well, full term babies, a number of screening criteria were examined for sensitivity and specificity characteristics when compared to a standard auditory brainstem response protocol. Results indicate that, for normal and special care neonates with a gestational age at test of 38-41 weeks, high sensitivity ( > 80%) could be obtained when a pass-fail criterion involving analysis of emission reproducibility, or emission reproducibility and emission response level, was set. Sensitivity was reduced for special care neonates who fell outside this age range. Specificity was found to be relatively low overall (always < 65%) and may relate to clinical factors in special care neonates not investigated in this study.

Audiological evaluation of very low birthweight infants

ABSTRACT A population of consecutively surviving very low birthweight (VLBW) infants comprising 41 infants (24 female) birthweight <1000 g and 108 infants (63 female) birthweight 1000–1500 g received detailed audiological evaluation. The audiological test battery comprised auditory brainstem evoked response (ABR) prior to hospital discharge, behavioural audiometry and tympanometry at 8–12 months and monitoring as necessary. The ABR results were interpreted with reference to a normative group of 36 full‐term infants (birthweight 2.4–4.5 kg). Of the 142 VLBW infants completing audiological evaluation, one (0.7%) had evidence of moderate‐severe high frequency sensorineural hearing loss, 83 (58.5%) evidence of conductive dysfunction (18 severe, 42 moderate and 23 mild) and only 58 (40.8%) normal hearing. The 19 infants with severe auditory impairment were more likely to have suffered moderate‐severe apnoea, two courses of mechanical ventilation, prolonged oxygen therapy and recurrent upper respiratory tract infections in the first year of life than infants without severe impairment (P<0.05). Because of the incidence of conductive pathology, difficulties occurred when attempting to compare ABR status at 36–42 weeks postmenstrual age with peripheral hearing status at 8–12 months as assessed by visual reinforcement orientation audiometry (VROA) and impedance audiometry. The most useful ABR test parameters as screening measures of peripheral auditory status were Wave I‐III‐V morphology, wave V threshold levels and wave V absolute latency values when used in combination as a test battery. Auditory brainstem evoked response performed at 36–42 weeks postmenstrual age combined with follow‐up tympanometry, may be regarded as a viable method of monitoring at risk VLBW infants that can be used before behavioural testing in isolation is reliable.

Measuring the ability of hearing impaired children to understand connected discourse: A comparison of two methods

Attempts to quantify the understanding of connected discourse have been based on: the number of embedded key words repeated correctly; the intelligibility ratings estimated by a listener; and the number of content-related questions answered correctly. This study was undertaken to compare the use of the latter two methods to measure the ability of hearing impaired children to understand connected discourse. Twenty-five normally hearing and 54 sensorineural hearing impaired Cantonese-speaking children rated how well they could understand a connected discourse passage, and answered content-related questions to show their level of understanding of the same passage. The effect of two different hearing aid frequency responses and two noise conditions on self-ratings and speech scores was also investigated. Both methods of assessment were able to demonstrate effects of hearing loss, frequency response and noise at approximately similar levels of significance. One of the findings from this study was the absence of any effect of testing method on the performance of the listeners to understand connected discourse. Consequently, either method can be used to provide essential information on the level of difficulty a hearing impaired child might experience in understanding connected speech in everyday life.

Auditory brainstem evoked response inter-peak latencies in very low birthweight infants

A population of very low birthweight (VLBW) infants consisting of 41 infants (24 female) less than 1000 g birthweight and 108 infants (63 female) 1000-1499 g together with a normative group of 36 full-term infants (18 female) 2400-4500 g birthweight were used to acquire auditory brainstem evoked response data. Inter-peak latency intervals were derived from the response and the data acquired were analysed across a range of related variables. The Wave V-III peak to peak latency interval was found to have significant age-related attributes together with an interactive birthweight effect, however no significant difference was established between the VLBW and normative groups when an age correction factor was applied.

A normative study of distortion-product otoacoustic emissions in 6-year-old schoolchildren.

Evoked otoacoustic emissions have demonstrated potential for application in the community-based hearing screening of paediatric populations. Distortion-product otoacoustic emissions (DPOAEs), as opposed to transient evoked otoacoustic emissions (TEOAEs), have not been extensively researched in this regard. The current study aimed to describe the range of DPOAE values obtained in a large cohort (1576 ears) of 6-year-old children in school settings and to examine possible ear asymmetry, gender and history of ear infection effects on the data. Results indicated a variety of significant effects, particularly in the high frequencies, for DPOAE signal-to-noise ratio. The measurement parameter, DPOAE amplitude (DP-amp), was found to display potentially less clinical applicability due to large standard deviation values. Use of descriptive normative data, as derived in the present investigation, may contribute toward future improvements in the hearing screening of 6-year-old schoolchildren.

Measuring the ability of children to understand everyday speech using computer technology : A normative study

Abstract The present study aimed to standardize The University of Queensland Understanding Everyday Speech Test (UQUEST), a computer-based auditory test for measuring the ability of children to understand everyday speech, for Australian school-aged children. Participants were 41 Grade 3, and 58 Grade 4 students (55 boys/44 girls), attending primary schools in the Brisbane and Sunshine Coast areas. Their mean age was 8.3 years (SD = 0.7). The speech material, consisting of 20 test passages, was delivered to a child via headphones at 65 dBSPL with the concurrent presentation of video animations. The child listened to these passages under four different listening conditions (quiet, signal-to-noise (SNR] = 10 dB, 5 dB and 0 dB). After tlze presentation of each passage, the child answered four content-related multiple-choice questions. The results revealed different mean speech scores for the 20 passages for each listening condition. In general, very high mean scores for the passages were obtained for the quiet and 10 dB SNR noise conditions, indicating a possible ceiling effect. However, for the harder listening conditions (SNR = 0 and 5 dB), the mean passage scores were comparatively lower (59–96%). The present study suggested the use of six passages, which are of comparatively equal difficulty, and free from the effects of gender and education level, across the two harder test conditions for future testing. Normative data and critical differences, based on the scores of these six passages, were established.

Hearing screening for school children with otitis media using otoacoustic emission measures

Abstract This study aimed to investigate the feasibility of using a technique other than pure-tone screening audiometry for the identification of slight or greater hearing loss in an urban population of indigenous Australian primary school children. Indigenous children have a higher prevalence of conductive hearing loss, associated with otitis media, than non-indigenous children in the same schools. Transient otoacoustic emission procedures were used as an alternative identification technique to pure tone screening audiometry. The otoacoustic emission results were compared with pure tone audiometry findings for the 150 Aboriginal and Torres Strait Islander children involved in the study. Comparison was made with pure tone audiometry for otoacoustic emission screening accuracy (in determining hearing loss >15 dB HL average) and also test practicality in urban school environments. Transient otoacoustic emission recording was found to show potential as a means of identifying slight or greater levels of heari...

On the effect of cross-hearing and clinical masking on the auditory brain-stem evoked response

The effects of cross-hearing from the non-test ear were examined during the acquisition of the auditory brain-stem evoked response (ABR). Effective masking levels were derived from a normal hearing subject and the results used to obtain masked versus unmasked ABR thresholds in varying types of unilateral hearing loss. The results indicate that in the presence of a hearing loss adequate masking of the non-test ear is essential for valid ABR results.

Predicting the understanding of Cantonese connected discourse

AbstractUnderstanding of connected discourse has a high face validity in estimating an individuals ability to understand everyday speech. In situations where a direct measure of connected discourse understanding is not possible, it would be beneficial to be able to predict a persons ability to understand connected discourse from other speech and audiometric parameters. The aim of this study was to predict the understanding of Cantonese connected discourse from (1) the maximum score from the performance-intensity function of a monosyllabic word-list test, (2) the results from a lexical tone test, (3) the results from the pure tone average and the monosyllabic word-list test, (4) the results from a sentence test, lexical tone test, vowel test and consonant test, and (5) the results from pure tone average, monosyllabic word-list and lexical tone tests. Twenty-seven normal-hearing and 55 sensorineural hearing-impaired school-aged children participated in the present study. All subjects were assessed using a...