OBJECTIVETo investigate the difference of transient evoked otoacoustic emissions (TEOAE) between neonates and adults with the frequency-specific approach.

METHODSTEOAE were recorded from 112 newborns (62 females, 58 males) who passed hearing screening, and 32 adults (17 females, 15 males) tested with pure-tone threshold equal or less than 20 dBHL. Band reproducibility, signal-to-noise rate (SNR) of frequency-band and half-octave frequency analysis of TEOAE amplitude was recorded respectively.

RESULTSSignificant differences were found in two groups, the higher entire TEOAE level found in newborn [(15.18 +/- 4.39) dB SPL] was higher than that of adults group [(9.51 +/- 4.12) dB SPL, P < 0.05]. The lowest wave reproducibility and SNR were in first frequency band (0.8 kHz) for neonate, and then, in last frequency band (4.0 kHz) were for young adults. For newborns, the highest band reproducibility and SNR were presented at fourth frequency band (3.2 kHz). However, for adults, the highest band reproducibility and SNR were presented at second frequency band (1.5 kHz). Frequency space of the SNR response peaks between neonates and adults was 1.7 kHz. The level difference was 7.09 dB SPL. Half octave frequency analysis shows a TEOAE response peaks in neonates was (10.50 +/- 5.09) dB SPL at the 2828 Hz, and in adults, it was (2.84 +/- 5.33) dB SPL at the 1414 Hz. Frequency space of the TEOAE response peaks between neonates and adults was 1414 Hz. Level differences of TEOAE response peaks was 7.66 dB SPL. TEOAE response peak in adult appear at 1.5 kHz, and then dropped down correlated to increase of frequency. From the first to the last testing frequency band, the difference of TEOAE level between neonate and adult was found to increase correlated to increase of frequency.

CONCLUSIONSTEOAE response level in newborn is higher than that in adult group. Further, the decrease of TEOAE response level presented more sharpens with the frequency increasing in adult. The frequency of TEOAE response peak in neonate (3.2 kHz) is higher than adult (1.5 kHz). The level of TEOAE response peak is also greater than adult.

Adult ; Female ; Humans ; Infant, Newborn ; Male ; Otoacoustic Emissions, Spontaneous ; physiology

In order to observe the DPOAE of guinea pigs under awake and anesthetic conditions, we invesitigated the amplitude of distortion product emission and I/O function curves and made a comparative analysis of their changes under different conditions. It was found that the amplitude of DPOAE and I/O curves did not show difference in the guinea pigs under awake and anesthetics conditions. We deem it credible and simple to measure DPOAE in the guinea pigs under awake condition, which is similar to measuring DPOAE in the guinea pigs under physiological condition.
Acoustic Stimulation ; Anesthesia ; Animals ; Cochlea ; physiology ; Female ; Guinea Pigs ; Male ; Otoacoustic Emissions, Spontaneous ; physiology

A new method in OAE's measurement by computer sound card is introduced. It is a measurement system using SF-1 detector. We designed the appropriate analog filter amplifier peripheral, utilized the mature technology of computer sound card, and recorded the OAE signal using Windows' API function programming by VB. The recorded signals can be analyzed by Matlab, such as digital filtering and Coherence average. The system is, in the main, cost-effective. The statistical results of the experiments proved the reliability of the method.
Acoustic Stimulation ; Cochlea ; physiology ; Evoked Potentials ; Hearing Tests ; instrumentation ; Humans ; Otoacoustic Emissions, Spontaneous ; physiology ; Signal Processing, Computer-Assisted ; instrumentation ; Sound

Child, Preschool ; Early Diagnosis ; Evoked Potentials, Auditory, Brain Stem ; Hearing ; physiology ; Hearing Loss ; diagnosis ; Humans ; Infant ; Otoacoustic Emissions, Spontaneous

Objective:This study aims to analyze the threshold changes in distortion product otoacoustic emissions（DPOAE） and auditory brainstem response（ABR） in adult Otof-/- mice before and after gene therapy, evaluating its effectiveness and exploring methods for assessing hearing recovery post-treatment. Methods:At the age of 4 weeks, adult Otof-/- mice received an inner ear injection of a therapeutic agent containing intein-mediated recombination of the OTOF gene, delivered via dual AAV vectors through the round window membrane（RWM）. Immunofluorescence staining assessed the proportion of inner ear hair cells with restored otoferlin expression and the number of synapses.Statistical analysis was performed to compare the DPOAE and ABR thresholds before and after the treatment. Results:AAV-PHP. eB demonstrates high transduction efficiency in inner ear hair cells. The therapeutic regimen corrected hearing loss in adult Otof-/- mice without impacting auditory function in wild-type mice. The changes in DPOAE and ABR thresholds after gene therapy are significantly correlated at 16 kHz. Post-treatment,a slight increase in DPOAE was observeds,followed by a recovery trend at 2 months post-treatment. Conclusion:Gene therapy significantly restored hearing in adult Otof-/- mice, though the surgical delivery may cause transient hearing damage. Precise and gentle surgical techniques are essential to maximize gene therapy's efficacy.
Mice ; Animals ; Otoacoustic Emissions, Spontaneous/physiology* ; Hearing/physiology* ; Ear, Inner ; Hearing Loss/therapy* ; Genetic Therapy ; Auditory Threshold/physiology* ; Evoked Potentials, Auditory, Brain Stem/physiology* ; Membrane Proteins

OBJECTIVEOtoacoustic emissions (OAE) and auditory brainstem responses (ABR) are tests widely used in neonatal hearing screening. This study aimed to investigate the differences and clinical value of distortion product otoacoustic emissions (DPOAE) and ABR in hearing screening of high-risk neonates admitted to a neonatal intensive care unit (NICU).

METHODSDPOAE and ABR were measured with the Smart-OAE analyser and the Smart-EP brain-stem electric response audiometry apparatus, respectively, in 600 high-risk neonates (1,200 ears). The testing results of DPOAE and ABR were compared.

RESULTSOf the 600 neonates (1,200 ears), the incidence of ABR abnormality (78.6%, 943/1,200) was remarkably higher than that of DPOAE abnormality (22.3%, 268/1,200). Two hundred and forty-one ears (20.8%) were negative and 252 (21%) were positive in both DPOAE and ABR tests. A total of 707 ears (58.9%) presented with a discordant result in DPOAE and ABR. The false positive and false negative rates of the DPOAE test were 6.0% (16/268) and 74.1% (691/932) respectively.

CONCLUSIONSIn high-risk neonates the diagnostic value of DPOAE for identification of hearing loss, when used alone, is limited. The ABR test appears to be more reliable for hearing screening in high-risk neonates. It is suggested that hearing screening for high-risk neonates should be conducted with ABR first, followed by OAE after failure on ABR.

Evoked Potentials, Auditory, Brain Stem ; physiology ; Female ; Hearing Tests ; methods ; Humans ; Infant, Newborn ; Intensive Care, Neonatal ; Male ; Neonatal Screening ; methods ; Otoacoustic Emissions, Spontaneous ; physiology

OBJECTIVETo investigate the changes of the potentials and structure of the guinea pig cochlear during whole cochlear perfusion with glutamate.

METHODSCochlear microphonics (CM), compound action potential (CAP), distortion product otoacoustic emission (DPOAE) and auditory brainstem response (ABR) were measured to indicate the cochlear functional properties during whole cochlear perfusion. The morphology of the cochlear was monitored by transmission electron microscopy.

RESULTSThere were no significant DPOAE changes before and after glutamate perfusion. CM I/O function maintained a nonlinear characteristic during infusion. After glutamate perfusion, ABR latencies were delayed. There was significant difference in CAP threshold before and after glutamate perfusion. The average CAP threshold was elevated 35 dB. The OHCs appeared normal, but IHCs and afferent dendrites showed cytoplasmic blebs after glutamate infusion.

CONCLUSIONSGlutamate is thought to be a primary amino acid neurotransmitter at the synapses formed by cochlear hair cells and spiral ganglion neurons. However, the excessive glutamate is neurotoxic for cells, and it can destroy the IHCs and spiral ganglion neurons. The present method can also be built up as an animal model of auditory neuropathy.

Animals ; Ear, External ; abnormalities ; physiopathology ; Evoked Potentials, Auditory, Brain Stem ; drug effects ; physiology ; Female ; Glutamic Acid ; pharmacology ; Guinea Pigs ; Male ; Otoacoustic Emissions, Spontaneous ; drug effects ; physiology

This study was designed to disclose the specific changes of distortion product otoacoustic emission (DPOAE), including DP-gram and I/O-gram in guinea pigs treated with GM for 10 and 17 days. Forty guinea pigs were divided into four groups:group I (treated with GM for 10 days), group II (treated with normal saline for 10 days), group III (treated with GM for 17 days), group IV (treated with normal saline for 17 days). DPOAE including DP-gram and DP-I/O was recorded by use of CELESTA 503 Cochlear Emission Analysis and the out hair cell loss was numerated. (1) The amplitude in group I showed significant reduction at frequencies of 4, 6, 8 kHz. There were significant differences, compared to group II (t=2.52, 1.92, 2.10, P<0.05). The amplitude in group III also decreased at frequencies of 3, 4, 6, 8 kHz. There were also significant differences compared to group IV (t=3.27, 2.81, 2.92, 3.13, P<0.01). The amplitude of DP-I/O in group I and group III at different frequencies and stimulus levels showed reduction. (2) At the level L1 <60 dB SPL, the stimulus levels to elicit a 0 dB response in group I and group III were higher than those in corresponding control groups, respectively. (3) The mean of threshold shift was 5.0+/-3.8 dB in group I and 25.0+/-6 dB in group III at 8 kHz frequency. (4) The out hair cell loss was 22.16% in group I and 48.36% in group III, both showed significant difference as compared to controls, respectively (P<0.01). The employment of DPOAE can be a useful tool in monitoring ototoxicity of GM for its sensitivity and specificity in guinea pigs treated with GM. The changes in DPOAE were consistent with those in histology.
Acoustic Stimulation ; methods ; Animals ; Cochlea ; drug effects ; physiopathology ; Female ; Gentamicins ; administration & dosage ; adverse effects ; Guinea Pigs ; Hair Cells, Auditory, Outer ; drug effects ; pathology ; Male ; Otoacoustic Emissions, Spontaneous ; physiology ; Perceptual Distortion ; drug effects ; physiology ; Random Allocation