Responses by the children with SLI indicated less impact of visual processing on speech perception than was seen with their normal peers. These results demonstrate that the difficulties with speech perception by SLI children extend beyond the auditory-only modality to include auditory-visual processing as well.
Background
The auditory brainstem response (ABR) test is frequently employed to estimate hearing sensitivity and assess the integrity of the ascending auditory system. In persons who cannot participate in conventional tests of hearing, a short-acting general anesthetic is used, recordings are obtained, and the results are compared with normative data. However, several factors (e.g., anesthesia, temperature changes) can contribute to delayed absolute and interpeak latencies, making it difficult to evaluate the integrity of the person’s auditory brainstem function.
Purpose
In this study, we investigated the latencies of ABR responses in children who received general anesthesia.
Research Design
Between subject.
Study Sample
Twelve children between the ages of 29 and 52 mo, most of whom exhibited a developmental delay but normal peripheral auditory function, comprised the anesthesia group. Twelve participants between the ages of 13 and 26 yr with normal hearing thresholds comprised the control group.
Data Collection and Analysis
ABRs from a single ear from children, recorded under general anesthesia, were retrospectively analyzed and compared to those obtained from a control group with no anesthesia. ABRs were generated using 80 dB nHL rarefaction click stimuli. T-tests, corrected for alpha slippage, were employed to examine latency differences between groups.
Results
There were significant delays in latencies for children evaluated under general anesthesia compared to the control group. Delays were observed for wave V and the interpeak intervals I–III, III–V, and I–V.
Conclusions
Our data suggest that caution is needed in interpreting neural function from ABR data recorded while a child is under general anesthesia.
This review is a guide to audiologists, speech-language pathologists, and early interventionists who work with individuals diagnosed with ANSD and/or their families. It highlights the need for more precise tools to describe the disorder in order to facilitate decisions about interventions and lead to better predictions of outcome.
Spontaneous otoacoustic emissions (SOAEs) and external tones (XTs) were used as primaries f2 and f1, respectively (frequency of f2 > f1) to create 2f1--f2 distortion product otoacoustic emissions (DPOAEs). Amplitude and frequency of the SOAEs, XTs, and DPOAEs were recorded by placing a sensitive microphone in the ear canal and extracted using fast Fourier transform analysis. XTs were presented to ten ears at SOAE/f1 ratios between 1.08 and 1.22. XTs were incremented in 5-dB steps and ranged from levels equal to the initial SOAE amplitudes to levels at which the SOAEs and DPOAEs were suppressed into the noise floor. Results indicated that DPOAE amplitudes and SOAE suppression characteristics were idiosyncratic. Despite the variability, the following trends were noted: (1) at larger frequency ratios, DPOAE generation and SOAE suppression were associated with greater XT levels; (2) DPOAE growth functions were characterized by slopes less than 1 dB/dB, a maximum, rollover and disappearance into the noise floor with increasing XT levels; (3) maximum amplitude DPOAEs were observed at frequencies approximately one-half octave lower than the SOAE (f2); (4) the presence of DPOAEs was associated with SOAE suppression; (5) the most common SOAE frequency shift, in the presence of XT stimulation, was a shift to a higher frequency.
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