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PubMedDate not supplied

Sensorineural hearing loss and Kawasaki disease: a prospective study.

PURPOSE: Kawasaki disease (KD) is an acute, self-limited vasculitis of infants and children that is now the most common cause of acquired heart disease in the pediatric age group in the United States and Japan. Reports have documented the association of acute KD with sensorineural hearing loss. To assess the prevalence of hearing loss following acute KD in a geographically and ethnically diverse population, a prospective, multicenter study of hearing loss in patients with KD was conducted. MATERIALS AND METHODS: Patients with acute KD were enrolled in 7 clinical centers and underwent a primary audiologic evaluation within 30 days of the onset of fever. Patients were subsequently reevaluated after resolution of the acute phase of the disease. A questionnaire assessing risk factors for hearing loss was also administered. RESULTS: A total of 62 patients were evaluated during the 29-month study period. At the first audiologic evaluation, 19 patients (30.6%) had sensorineural hearing loss, 6 patients (9.7%) had conductive hearing loss, 17 patients (27.4%) had normal hearing, and 20 patients (32.3%) had inconclusive studies. Overall, 2 of 36 patients (5.5%) had sensorineural hearing loss documented on their second audiologic evaluation. No risk factors for hearing loss were identified by the questionnaire. CONCLUSIONS: Transient sensorineural hearing loss (20 to 35 dB) is a frequent complication of acute KD and may be related to salicylate toxicity in some patients. Persistent sensorineural hearing loss is uncommon. Parents and primary care providers should be made aware of the potential for persistent sensorineural hearing loss following resolution of KD, but routine audiologic screening of this patient population does not appear to be warranted.

Acoustic Impedance Tests↗
PubMed1998

[Comparison of methods for reducing residual noise in suprathreshold early auditory evoked potential registration].

BACKGROUND: The level of residual noise in auditory brainstem responses (ABR) depends not only on the number of averages but also on the amplitude of background noise and on the frequency of artifacts. This paper describes the influence of digital filtering and of different methods of artifact suppression on the residual noise of ABRs. METHOD: Amplitude of background noise was estimated for 1033 ABRs recorded under suprathreshold stimulation (70 and 90 dB nHL) in 251 subjects. In 45 ABR recordings in 15 subjects, all 4000 individual sweeps were stored for off-line simulation. The power spectrum of background noise was investigated using an FFT analyzer. RESULTS: A great variability of mean noise amplitude was found both between subjects and in the recordings for each subject. Depending on the slope of the analogue 100-Hz high-pass filter, mean RMS values of background noise of 4.2 microV (6 dB/Oct.) and 2.5 microV (12 dB/Oct.), respectively, were found. Digital high pass filtering before averaging was found to increase the signal-to-noise ratio (SNR) considerably. CONCLUSIONS: Results indicate that (i) effective suppression of low-frequency noise components can only be achieved by zero phase digital filtering and (ii) if clipping of noise amplitude to 25 microV is used, optimized artifact rejection as weighted averaging or adopted artifact rejection levels have only small effect on the SNR.

Adolescent↗
PubMed1995

[Diagnostic intra-meatal acoustic neurinoma--the role of acoustically evoked brain stem potentials and other otoneurologic studies].

BACKGROUND: Today intracanalicular acoustic neuromas are diagnosed very early by magnetic resonance imaging (MRI). The purpose of this study was to test the capability of brainstem evoked response audiometry (BERA) for detecting these small tumors. PATIENTS: Seventeen of 91 consecutive cases with acoustic neuromas treated at our department suffered from purely intracanalicular tumors. For these 17 patients we reviewed their medical history, clinical otoneurologic examination, audiometry, auditory evoked brainstem audiometry, electronystagmography, and MRI studies. RESULTS: In 13 of 17 patients (76.5%) auditory evoked brainstem audiometry was indicative of a suspected retrocochlear lesion, whereas in 4 cases BERA did not indicate such a lesion. CONCLUSIONS: The symptoms of these patients are described in detail. The role of auditory evoked brainstem audiometry and other otoneurologic test methods for detection of intracanalicular acoustic neuromas will be discussed.

Audiometry, Evoked Response↗
PubMed2003

Effects of isoflurane on the auditory brainstem responses and middle latency responses of rats.

OBJECTIVE: To evaluate the effects of a volatile anesthetic, isoflurane, on auditory brainstem responses (ABRs) and middle latency responses (MLRs) recorded in rats. MATERIAL AND METHODS: ABRs and MLRs evoked by click stimuli were simultaneously recorded in eight rats in the awake condition and during anesthesia with isoflurane at clinically relevant concentrations. RESULTS: Vertex-recorded ABRs showed a significant increase in the latency of waves I-IV during anesthesia and the latency changes appeared to be significantly related to the isoflurane concentration. The I-IV interval also appeared to be significantly increased in comparison to the awake condition, while minor changes in ABR amplitudes were induced by isoflurane. MLRs, which were recorded by means of epidural electrodes implanted over the auditory cortex, appeared to be attenuated in amplitude and increased in latency during anesthesia. Only latency changes appeared to be significantly related to the isoflurane concentration. Moreover, "bursts" of high amplitude MLRs were observed during anesthesia at each concentration. CONCLUSION: The present findings indicate that both ABR and MLR latencies are increased by isoflurane in a concentration-dependent manner, whilst the anesthetic-induced attenuation in amplitude does not appear to be related to the isoflurane concentration.

Animals↗
PubMed2002

c-fos mRNA induction in acute and chronic audiogenic stress: possible role of the orbitofrontal cortex in habituation.

To study putative brain circuits involved in habituation to stress, rats were exposed daily (30 min for 15 days) to an environment in the presence (Chronic) or absence (Acute) of loud noise (105 dB sound pressure level--SPL A Scale). Behavioral and endocrine measures of stress were taken throughout this habituation period, and both measures displayed strong habituation in the Chronic group. All rats were killed immediately after the day 16 exposure, constituting an acute stressor for the Acute group, and regional brain activity was assessed using c-fos mRNA induction with in situ hybridization. Hearing damage could not easily explain these results because additional rats exposed to a similar stress protocol exhibited no changes in auditory brainstem evoked potentials. c-fos mRNA induction in the central auditory system was similar between the Acute and Chronic groups, particularly at lower auditory processing levels, also arguing against a simple reduction in auditory processing in the chronically stressed rats. However, c-fos mRNA expression was reduced in chronically, as compared to acutely, stressed rats in several regions previously implicated in audiogenic stress (lateral septum, bed nucleus of the stria terminalis, some preoptic areas, and the paraventricular hypothalamic nucleus). Interestingly, the orbitofrontal cortex was the only region displaying higher c-fos mRNA induction in the chronically as compared to acutely stressed rats. This region has connections to several stress-responsive areas and may thus be a critical region actively inhibiting stress.

Animals↗
PubMed1987

Pure word deafness following bilateral lesions. A psychophysical analysis.

A detailed clinical and psychophysical study of a woman who had developed pure word deafness associated with amusia after bilateral temporoparietal destructions is reported. The patient had a defect in temporal resolution encompassing auditory, visual and somatosensory modalities, but the clinical defect was limited to the auditory sphere. Auditory comprehension did not improve even if she was spoken to slowly, although marked improvement of temporal resolution was observed as the duration of a nonlinguistic sound was extended. Also, she exhibited a supramodal defect in the perception and reproduction of rhythm, which was rate-dependent. These and other findings led to the following conclusions: the auditory modality is much more dependent on temporal resolution than other sensory modalities; for a full understanding of the mechanism of pure word deafness, not only the defect of temporal resolution but also many other factors, for example, defective discrimination of loudness, pitch or tone duration have to be taken into consideration; and rhythm sense strongly depends on a supramodal capacity of temporal resolution.

Adult↗
PubMed2002

Maturation of the auditory change detection response in infants: a longitudinal ERP study.

Mismatch negativity (MMN) is a negative component of auditory event-related potential (ERP), reflecting the brain's automatic change detection process. In the present study we investigated the development of the pitch change detection, as indexed by the MMN, in the same infants from birth until 12 months of age. The MMN was identified in approximately 75% of infants at each age, being relatively stable in latency and amplitude at the group level across the ages studied. However, within the same subjects the MMN substantially varied from age to age. The inspection of individual data revealed a possible source of this variability: in a portion of 3- to 9-month-old infants, a large-amplitude positive component commenced at the latency of the MMN and thus might have masked it. The results of the additional experiment, employing distracting novel sounds in 2-year-old infants and newborns, suggested that the observed positive component could represent an infant analogue of the adult P3a response, indexing an involuntary orienting of attention. Therefore, the variability from age to age might be, at least partially, caused by the differences in degree of infants' orienting, resulting in the reduction of the scalp recorded mismatch negativity in recordings when the orienting P3a positivity was elicited.

Acoustic Stimulation↗
PubMedDate not supplied

Objective versus visual detection of the auditory brain stem response.

The use of objective (mathematical) procedures in auditory brain stem response (ABR) testing has been suggested in order to eliminate the subjectivity of visual judgments and to increase sensitivity of detection. This investigation compared with effectiveness of visual and objective detection of the ABR. Auditory brain stem responses were obtained in normal adults at several click levels. An equal number of waveforms obtained without stimulation were used to measure false-positive responses. Visual judgments of ABR presence were made by four experienced raters. Objective analysis was accomplished using three methods: correlation, variance ratio, and multiple pre-post z tests. The mean sensitivity score was highest for visual detection, followed in order by the correlation, variance ratio, and multiple z test methods. While visual scoring was statistically the most sensitive, the practical difference between measures was small. In addition, there was considerable disagreement between raters in their judgments. Therefore, the most sensitive of the objective measures--correlation, is considered to be a useful detection procedure to eliminate observer bias and to achieve consistency of scoring.

Adult↗
PubMed1992

Interaction of click intensity and cochlear hearing loss on auditory brain stem response wave V latency.

Auditory brain stem responses (ABRs) to 95, 80, 60, 40, and 30 dB nHL clicks were retrospectively studied from 103 patients (194 ears) with various degrees of cochlear impairment. Hearing loss and sample size were balanced across gender. Results indicate that the slope of the wave V latency versus 4000 Hz hearing loss function doubles as click intensity is decreased from 80 (0.01 msec/dB HL) to 60 nHL (0.02 msec/dB HL). Overall results indicate a slope increase of 0.0004 msec for each decibel decrease in click intensity from 95 to 30 dB nHL. Intersubject variability increased with increased hearing loss and/or decreased stimulus intensity. The effects of hearing loss on wave V latency are minimal, and intersubject variability is less if high-intensity clicks (greater than or equal to 95 dB nHL) are used. No differences in the effects of hearing loss on wave V latency were seen between males and females. Latency corrections for cochlear hearing loss should, therefore, consider stimulus intensity.

Acoustic Stimulation↗
PubMed1992

Effect of hearing loss of cochlear origin on the auditory brain stem response.

Auditory brain stem response (ABR) testing is widely used to detect lesions of the auditory neural pathways. The ABR waves depend not only on the integrity of the neural pathways, but also on the condition of the cochlea. To properly interpret the ABR response, it is necessary to understand the effects of cochlear hearing loss on the ABR wave latencies. We studied two populations of subjects with cochlear hearing loss: one with varying degrees of high-frequency hearing loss and the other with varying degrees of flat configuration hearing loss. The degree of cochlear hearing loss was quantified in several different ways and subjected to one linear and three nonlinear regression analyses to test for accuracy in predicting ABR wave latencies and interpeak intervals (waves I, III, V, I-V, I-III, and III-V) for three click intensities. Hearing loss levels from 2 to 6 kHz, in particular 4 kHz, were superior to other audiometric test frequencies as predictors of ABR wave latencies for the group with the high-frequency losses. No particular characterization was found to be superior for the flat hearing loss configurations. From these results, modeled predictions of wave latencies as a function of degree and configuration of hearing loss were made. The modeled predictions are then used to suggest guidelines for interpretations of ABR results where hearing impaired patients are involved.

Adult↗
PubMed2000

Otoacoustic emissions and tympanometry in children with otitis media.

OBJECTIVE: To examine otoacoustic emission and tympanometric findings in children with surgically confirmed middle ear effusion (MEE). DESIGN: A total of 102 children aged 0.7 to 11.4 yr undergoing surgery because of otitis media were included in the study. A tympanometric examination and transient evoked otoacoustic emission (TEOAE) measurement were performed on each ear before myringotomy. MEE was aspirated, weighed and classified as mucoid or nonmucoid. TEOAE measurements were compared with the quantity and quality of MEE and to the tympanometric findings. RESULTS: Fifty (72%) ears out of the 65 ears containing effusion showed reduced TEOAE. The quantity of effusion was associated significantly (p < 0.001) with the TEOAE responses, and mucoid effusion reduced the emissions more than nonmucoid. The sensitivity of tympanometry in identifying the ears without recordable TEOAE was 73% and the specificity 81%. CONCLUSION: MEE results in a significant reduction in TEOAEs even when the effusion is nonmucoid. This suggests that transmission of acoustic energy to and from the middle ear is altered in children experiencing any form of otitis media with effusion.

Acoustic Impedance Tests↗
PubMed2003

Comparison of tone burst and tapping evocation of myogenic potentials in patients with chronic otitis media.

OBJECTIVE: Vestibular evoked myogenic potential (VEMP) has recently been broadly studied in cochleo-vestibular disorders to elucidate its mechanism. Because it is evoked by loud sound stimulation, impairment of the sound transmission through the middle ear may affect VEMP results. This study aims to compare the response rate of VEMPs using the tone burst method and the tapping method in patients with chronic otitis media (COM). DESIGN: Fourteen patients (22 ears) with conductive hearing loss due to COM were subjected to VEMP tests using both the tone burst method and the tapping method. Each ear was stimulated by a short-tone burst (95 dB nHL, 500 Hz), followed by tapping on the forehead with a tendon hammer, 200 times at a frequency of 5 Hz. RESULTS: Thirteen (59%) of the 22 ears showed positive VEMPs using the tone burst method, whereas 20 ears (91%) displayed positive VEMPs by the tapping method (p < 0.05). The latencies of wave p13 and n23, and the amplitude p13-n23 using the tone burst method were 13.4 +/- 4.1 msec, 20.5 +/- 4.6 msec, and 77.2 +/- 17.2 microV, respectively. These results do not significantly differ from those obtained using the tapping method. In ears with perforated eardrums (N = 11), five ears (45%) displayed positive VEMPs by the tone burst method; compared with nine ears (82%) with positive VEMPs using the tapping method, representing a nonsignificant difference. In ears with healed eardrums (N = 11), eight ears exhibited positive VEMPs by tone burst, with a mean air-bone gap of 25.6 +/- 15.2 dB at 500 Hz, in contrast to a gap of 30.0 +/- 22.9 dB in three ears without VEMPs, indicating no significant difference. CONCLUSIONS: When stimulating sound is attenuated by middle ear pathology, VEMPs are expected to be poorly elicited. Under such conditions, myogenic potentials may be evoked with the tapping method to elicit the absent VEMPs that result from middle ear or inner ear pathology.

Acoustic Stimulation↗
PubMed1996

Infant hearing screening with an automated auditory brainstem response screener and the auditory brainstem response.

From 1653 babies hospitalized in the Veterans General Hospital-Taipei from 1993 to 1995, 260 infants at risk of hearing impairment were selected. The risk criteria of hearing impairment for neonates were based on the recommendation of the US Joint Committee on Infant Hearing, 1990 Position Statement. All these infants were screened with the Algo-1 Plus, an automated auditory brainstem response (ABR) screener at a mean postconceptional age of 40.7 +/- 4.5 weeks. Thirty-nine cases (39/260, 15%) involving 57 ears (57/520, 11%), failed the screening. Except for one infant who died, the babies had an ABR test for both air- and bone-conducted stimuli and an otological examination. The case-specific incidence of conductive hearing deficit at the initial ABR test was 5.4%. The prevalence of sensorineural hearing deficits was between 2.3% confirmed and 3.1% including infants who did not have follow-up tests. The kappa-value that indicated agreement between the Algo-1 and ABR results was 0.64, and the overall efficiency of using Algo-1 to correctly identify pass or failure of the ABR was 83%.

Audiometry, Evoked Response↗
PubMed2003

An account of monaural phase sensitivity.

Listeners can detect phase differences between the envelopes of sounds occupying remote frequency regions, and between the fine structures of partials that interact within a single auditory filter. They are insensitive to phase differences between partials that differ sufficiently in frequency to preclude within-channel interactions. A new model is proposed that can account for all three of these findings, and which, unlike currently popular approaches, does not discard across-channel timing information. Sensitivity is predicted quantitatively by analyzing the output of a cochlear model using a spectro-temporal decomposition inspired by responses of neurons in the auditory cortex, and by computing a distance metric between the responses to two stimuli to be discriminated. Discriminations successfully modeled include phase differences between pairs of bandpass filtered harmonic complexes, and between pairs of sinusoidally amplitude modulated tones, discrimination between amplitude and frequency modulation, and discrimination of transient signals differing only in their phase spectra ("Huffman sequences").

Attention↗
PubMed2003

Phase effects in masking: within- versus across-channel processes.

The effects of bandwidth and component phase on masking were investigated using 200-ms narrowband (1-ERB(N)) and broadband (5-ERB(N)) cosine-phase (CP) and random-phase (RP) harmonic complex maskers, centered at 1 or 6 kHz. A continuous notched-noise was used to restrict off-frequency listening. The masker fundamental frequency (F0) was 25 Hz. In experiment 1, thresholds were measured for sinusoidal signals at 1 and 6 kHz, gated with the maskers. Thresholds were lower in the CP than in the RP masker, for both bandwidths, but the effect was markedly greater for the wider bandwidth. For the CP maskers, thresholds were markedly lower for the 5-ERB(N) than for the 1-ERB(N) bandwidth; for the RP maskers, there was a small effect in the opposite direction. Experiment 2 used 1- and 6-kHz CP maskers. The masker components in the ERB(N) around the signal frequency were presented to one ear, and the remaining components were presented contralaterally. Thresholds were much higher than when all components were presented to the same ear, and were higher than for the 1-ERB(N) masker alone, suggesting that the low thresholds for broadband monaural presentation do not depend on "high level" across-channel comparisons. Simultaneous masked thresholds could be predicted well using a model based on a simulated auditory filter, a level-dependent compressive nonlinearity, and a sliding temporal integrator; it was not necessary to assume the involvement of across-channel processes or of selective listening in the masker dips.

Adult↗
PubMed2004

Chronic excitotoxicity in the guinea pig cochlea induces temporary functional deficits without disrupting otoacoustic emissions.

Brief cochlear excitotoxicity produces temporary neural swelling and transient deficits in auditory sensitivity; however, the consequences of long-lasting excitotoxic insult have not been tested. Chronic intra-cochlear infusion of the glutamate agonist AMPA (a-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid) resulted in functional deficits in the sound-evoked auditory brainstem response, as well as in behavioral measures of hearing. The electrophysiological deficits were similar to those observed following acute infusion of AMPA into the cochlea; however, the concentration-response curve was significantly shifted as a consequence of the slower infusion rate used with chronic cochlear administration. As observed following acute excitotoxic insult, complete functional recovery was evident within 7 days of discontinuing the AMPA infusion. Distortion product otoacoustic emissions were not affected by chronic AMPA infusion, suggesting that trauma to outer hair cells did not contribute to AMPA-induced deficits in acoustic sensitivity. Results from the current experiment address the permanence of deficits induced by chronic (14 day) excitotoxic insult as well as deficits in psychophysical detection of longer duration acoustic signals.

Animals↗