Analysis Of Otoacoustic Emissions Research Articles

Hearing Evaluation of Neonates with Hyperbilirubinemia by Otoacoustic Emissions and Brain Stem Evoked Response Audiometry

Introduction: Neonatal hyperbilirubinemia is one of the most important factors affecting the auditory system and can cause sensorineural hearing loss. This study evaluated the hearing status in neonates with hyperbilirubinemia and results obtained from Otoacoustic emissions (OAE) and Brain stem evoked response audiometry (BERA) analysis were compared with each other’s.Material and Methods:This study was performed on fifty eligible term neonates with hyperbilirubinemia requiring either phototherapy or exchange transfusion or both. Hearing analysis was done by OAE and BERA.Results: Out of fifty eligible neonates, twenty one (42%) had hearing impairment as per OAE analysis, eight (16%) had hearing impairment; two (4%) neonate had inconclusive hearing analysis as per BERA analysis. Out of twenty one neonates having hearing impairment by OAE only five had hearing impairment as per BERA analysis. While the eight neonates who had hearing impairment by BERA analysis, five had hearing impairment by OAE.Conclusion: The study showed hearing impairment by OAE analysis in 42% neonates while the BERA analysis showed hearing impairment in 16 % neonates. The increased level of Serum bilirubin has not shown the increase in percentage of hearing impairment.J Nepal Paediatr Soc 2016;36(3):310-313

Contribution of audiovestibular tests to the topographic diagnosis of sudden deafness.

Summary Introduction: Sudden hearing loss (SHL) is an ENT emergency defined as sensorineural hearing loss (SNHL) ≥ 30 dB HL affecting at least 3 consecutive tonal frequencies, showing a sudden onset, and occurring within 3 days. In cases of SHL, a detailed investigation should be performed in order to determine the etiology and provide the best treatment. Otoacoustic emission (OAE) analysis, electronystagmography (ENG), bithermal caloric test (BCT), and vestibular evoked myogenic potential (VEMP) assessments may be used in addition to a number of auxiliary methods to determine the topographic diagnosis. Objective To evaluate the contribution of OAE analysis, BCT, VEMP assessment, and magnetic resonance imaging (MRI) to the topographic diagnosis of SHL. Method Cross-sectional and retrospective studies of 21 patients with SHL, as defined above, were performed. The patients underwent the following exams: audiometry, tympanometry, OAE analysis, BCT, VEMP assessment, and MRI. Sex, affected side, degree of hearing loss, and cochleovestibular test results were described and correlated with MRI findings. Student's t-test was used for analysis of qualitative variables (p < 0.05). Results The mean age of the 21 patients assessed was 52.5 ± 15.3 years; 13 (61.9%) were women and 8 (38.1%) were men. Most (55%) had severe hearing loss. MRI changes were found in 20% of the cases. When the audiovestibular test results were added to the MRI findings, the topographic SHL diagnosis rate increased from 20% to 45%. Conclusion Only combined analysis via several examinations provides a precise topographic diagnosis. Isolated data do not provide sufficient evidence to establish the extent of involvement and, hence, a possible etiology.

Identification of otoacoustic emissions components by means of adaptive approximations.

Clicks and a set of tone bursts covering the same frequency band were applied as a stimuli evoking otoacoustic emissions (OAE). Recorded otoacoustic emissions were decomposed into the basic waveforms by means of high-resolution adaptive time-frequency approximation method based on the matching pursuit algorithm. The method allows for description of the signal components in terms of frequencies, time occurrences, time spans, and energy. The analysis of OAE's energy density distributions in time-frequency space revealed that click responses can be considered as linear superpositions of responses to tone bursts, The frequency-latency relationship was studied and compared with earlier works. The method made possible the exhaustive description of the resonant modes specific for given subject/ear. They were characterized not only by the close frequencies appearing for different tones, but they usually had similar latencies and time spans. Short-time and long-time resonant modes were identified. The second ones might be connected with spontaneous emissions. The method opens new perspectives in studying the fine structure of the OAE and testing of the theoretical models.

Absence of otoacoustic emissions in insulin-dependent diabetic patients: Is there evidence for diabetic cochleopathy?

In order to evaluate cochlear function in Type 1 diabetes mellitus, this study analyses otoacoustic emissions (OAEs) on normal hearing subjects with diabetes and on controls. Patients with Type 1 diabetes ( n=60), with a mean age of 31±6.23 years, mean disease duration of 17.5±8.9 years, and mean HbA1c of 8.1±1.8%, of whom 43% had signs of retinopathy and 28% had clinical signs of neuropathy, were studied. All patients underwent an OAE analysis and brainstem-evoked potentials. Fifty-eight normal volunteers were used as controls for the OAE analysis. Seventeen patients (28.3%) had no OAEs in at least one ear and 10% in both ears. The mean intensity of the response was lower in diabetic subjects [7.1±4.4 vs. 10.9±9.3 dB SPL (sound pressure level)] than in controls. The cochlear impairment was over 5 dB for the 1-kHz frequency, which is the critical level for speech understanding. These findings suggest that cochleopathy can be detected in a relatively high proportion of subjects with Type 1 diabetes in spite of a normal audiometric hearing threshold.

Spectral–temporal analysis of OAEs in normal-hearing humans: Latencies, fine structure, and multiple internal reflections

Otoacoustic emissions (OAEs) display complexity in both time and frequency, which may be obscured in traditional response analyses. Time-frequency representations (TFR) of the eliciting stimuli and the recorded OAE provide a tool to understand this complexity. TFRs were applied to stimulus-frequency (SF) and distortion-product (DP) OAEs obtained in 25 normal-hearing adults, using three classes of stimuli: continuous tones, gated tones (tonal stimuli with well-defined onset, steady state and decay), and tone pips (band-limited impulses). Synchronous spontaneous OAEs were measured using clicks to assess their contributions to TFRs of SFOAE and DPOAEs. A common form of TFR generated from tone-pips is a collection of frequency-specific components, with each component characterized by one or more brief segments or a single long-duration segment. Frequency-pulling effects between components were observed, however, little evidence was found for interactions within transient SFOAEs in the form of intermodulation distortion. TFRs show evidence for strong emission regions or cochlear ‘‘hot spots’’ within pip responses, and multiple internal reflections within gated and pip responses. The resulting measures of OAE latencies are compared with model predictions. Thus, the TFR analysis provides a quantitative tool for measuring the spectral-temporal organization of multiple-component OAEs. [Work supported by NIH, DC003784.]

Clinical application of otoacoustic emissions: what do we know about factors influencing measurement and analysis?

Three electrophysiologic audiologic procedures-aural immittance measurement, auditory brainstem response (ABR), and otoacoustic emissions (OAE)- were first described in the 1970's. Immittance measurement and ABR have contributed importantly for years to the assessment of auditory function in children and adults, whereas OAEs have not yet been incorporated into the everyday audiology test battery. In this article, we argue that the transition from OAE measurement by hearing scientists in laboratory settings to routine application by audiologists in the clinic will be greatly facilitated by (1) comprehensive, large-scale studies of the effects of subject characteristics, such as gender and age (from infancy to advancing adulthood), on both transient evoked (TEOAE) and distortion product (DPOAE) otoacoustic emissions; (2) clinical investigations of TEOAE and DPOAE in sizeable patient populations with specific neurotologic diagnoses; (3) guidelines for OAE test protocols in clinical environments; and (4) clear criteria for OAE analysis in clinical populations.