OBJECTIVE: To study the relationship of distortion product in cochlea with cochlear activity and hearing. METHOD: Time variances of distortion product of basilar membrane vibration in vitro guineapig cochlea were observed by laser interferometry. RESULT: Within half hour after a cochlea was isolated from a guineapig, distortion product accompanied with two-tone inhibition in cochlea, can be observed. As time passed, distortion product and two-tone inhibition effect disappeared at the same time. After that, the membrane contiune vibrating in response to the sound stimulus, but the vibration amplitude decreased obviously and continued decreasing until it disappeared completely. CONCLUSION Distortion product in cochlea is a symbol of cochlear activity which makes the membrane respond in large amplitude vibration to sound stimulus and exhibit two-tone inhibition. The former makes the hearing highly sensitive to sound stimulus, the later makes the hearing perform information abstract well.
Acoustic Stimulation ; Animals ; Basilar Membrane ; physiology ; Cochlea ; physiology ; Guinea Pigs ; Hearing ; physiology ; Hearing Tests ; Interferometry ; Sound

OBJECTIVETo explore the relationship between hearing level and soft palate movement after palatoplasty and to verify the importance of recovery of soft palate movement function for improving the middle ear function as well as reducing the hearing loss.

METHODSA total of 64 non-syndromic cleft palate patients were selected and the lateral cephalometric radiographs were taken. The patients hearing level was evaluated by the pure tone hearing threshold examination. This study also analyzed the correlation between hearing threshold of the patients after palatoplasty and the soft palate elevation angle and velopharyngeal rate respectively.

RESULTSKendall correlation analysis revealed that the correlation coefficient between hearing threshold and the soft palate elevation angle after palatoplasty was -0.339 (r = -0.339, P < 0.01).The correlation showed a negative correlation. The hearing threshold decreased as the soft palate elevation angle increased. After palatoplasty, the correlation coefficient between the hearing threshold and the rate of velopharyngeal closure was -0.277 (r = -0.277, P < 0.01). The correlation showed a negative correlation. While, The hearing threshold decreased with the increase of velopharyngeal closure rate. The hearing threshold was correlated with soft palate elevation angle and velpharyngeal closure rate.

CONCLUSIONSThe movement of soft palate and velopharyngeal closure function after palatoplasty both have impact on patient hearing level. In terms of the influence level, the movement of soft palate has a higher level of impact on patient hearing level than velopharygeal closure function.

Auditory Threshold ; physiology ; Cleft Palate ; physiopathology ; surgery ; Follow-Up Studies ; Hearing ; physiology ; Hearing Tests ; Humans ; Palate, Soft ; physiology ; Velopharyngeal Insufficiency ; physiopathology ; surgery ; Velopharyngeal Sphincter ; physiology

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

Auditory Perception ; physiology ; Child Development ; physiology ; Hearing ; physiology ; Humans ; Infant, Newborn ; growth & development ; Intensive Care Units, Neonatal ; Noise ; adverse effects

BACKGROUNDMany factors interfering with a listener attempting to grasp speech in noisy environments. The spatial hearing by which speech and noise can be spatially separated may play a crucial role in speech recognition in the presence of competing noise. This study aimed to assess whether, and to what degree, spatial hearing benefit speech recognition in young normal-hearing participants in both quiet and noisy environments.

METHODSTwenty-eight young participants were tested by Mandarin Hearing In Noise Test (MHINT) in quiet and noisy environments. The assessment method used was characterized by modifications of speech and noise configurations, as well as by changes of speech presentation mode. The benefit of spatial hearing was measured by speech recognition threshold (SRT) variation between speech condition 1 (SC1) and speech condition 2 (SC2).

RESULTSThere was no significant difference found in the SRT between SC1 and SC2 in quiet. SRT in SC1 was about 4.2 dB lower than that in SC2, both in speech-shaped and four-babble noise conditions. SRTs measured in both SC1 and SC2 were lower in the speech-shaped noise condition than in the four-babble noise condition.

CONCLUSIONSpatial hearing in young normal-hearing participants contribute to speech recognition in noisy environments, but provide no benefit to speech recognition in quiet environments, which may be due to the offset of auditory extrinsic redundancy against the lack of spatial hearing.

Adolescent ; Adult ; Auditory Threshold ; physiology ; Female ; Hearing ; physiology ; Humans ; Male ; Noise ; Speech Perception ; physiology ; Speech Reception Threshold Test ; Young Adult

OBJECTIVEThe aim of this study is to assess of cochlear implantation in children with auditory neuropathy and cochlear nerve aplasia by using Categories of Auditory Performance (CAP) and Speech Intelligibility Rating (SIR).

METHODSTwenty one children with cochlear implants participated in this study. They all received cochlear implant surgery at our hospital from January 2004 to October 2010. All children had hearing aid trial and hearing and speech rehabilitation before surgery at least three months.Nine children (7 male, 2 female) were diagnosed with auditory neuropathy, twelve (7 male, 5 female) with cochlear nerve aplasia. Twenty children (10 male, 10 female) with sensorineural hearing loss served as a control group. All the children received cochlear implant for more than six months. Forty two children with normal hearing served as another control group which were divided into three subgroups according to their age.Group A included 18 children aged under two yrs, group B consisted of 16 children aged from two to four yrs and group C comprised eight children aged above four yrs. CAP and SIR were used to evaluate among all the children and the scores were compared.

RESULTSThe CAP scores of children with auditory neuropathy, cochlear nerve aplasia, sensorial neural hearing loss and the three subgroups children with normal hearing were 4.44 ± 1.50, 4.83 ± 1.69, 4.55 ± 1.66, 5.22 ± 1.11, 6.75 ± 0.45 and 7.00 ± 0.00 respectively, and SIR scores were 2.66 ± 1.11, 2.33 ± 1.15, 2.40 ± 0.75, 2.56 ± 1.04, 4.12 ± 0.81 and 5.00 ± 0.00 respectively. There were significant differences among the six groups for CAP scores(χ(2) = 35.481, P < 0.001) and SIR scores(χ(2) = 40.549, P < 0.001).No significant differences for CAP and SIR scores were observed between children with auditory neuropathy/cochlear nerve aplasia and sensorial neural hearing loss as well as group A (P > 0.05 for each), and there were significant differences were shown between children with auditory neuropathy/cochlear nerve aplasia and group B as well as group C (P < 0.01 for each aplasia).

CONCLUSIONSThe auditory and speech capabilities of children with auditory neuropathy and cochlear nerve deficiency can can get benefits from cochlear implants as children with sensorineural hearing loss, however not achieve the level of those with normal hearing after cochlear implantation. The long term effects still need follow-up and evaluation.

Child ; Cochlear Implantation ; statistics & numerical data ; Cochlear Implants ; Cochlear Nerve ; physiology ; Female ; Hearing ; Hearing Aids ; Hearing Loss, Central ; surgery ; Hearing Loss, Sensorineural ; Hearing Tests ; Humans ; Male ; Speech ; Speech Intelligibility ; Speech Perception ; Vestibulocochlear Nerve Diseases

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

OBJECTIVETo compare acoustically evoked short latency negative responses (ASNR) elicited from normal and profound hearing loss guinea pig ears and to confirm their vestibular nuclei origination.

METHODSForty healthy guinea pigs were employed in the experiment, which were randomly divided into the control group (8 subjects, 16 ears), the masking group (16 subjects, 32 ears) and the deafened group (16 subjects, 32 ears). Air conductive white noise was chosen for masking. Masking dilemma was avoidable by an appropriate 15 dB gap between stimulus and masking sound. Both the masking group and the deafened group were further divided into ASNR group and non-ASNR group based on the presence of ASNR. Electrolytic lesion was conducted to the vestibular nuclei, followed by ABR/ASNR recording. The lesioned brainstem slices were microscopically verified.

RESULTSIn the masking group, ASNR were present in 24 ears (75.0%, 24/32) and 12 ears (46.2%, 12/26) in deafened group, showing statistically higher presence rate for masking group (χ(2)=5.07, P=0.024). There were no significant differences for the ASNR threshold and latency between the masking ASNR group and the deafened ASNR group. For the two ASNR groups, electrolytic destruction to the vestibular nuclei subsequently eliminated the ASNR. Brainstem slice proved the accurate sites of electrolytic lesion.

CONCLUSIONModerate white noise masking prevents hearing system potential overlap without affecting vestibular system, therefore, ASNR is successfully elicited in normal guinea pigs. Both ASNRs from normal and deafened guinea pigs are of similar natures and origination from, the vestibular nuclei.

Animals ; Deafness ; physiopathology ; Evoked Potentials, Auditory, Brain Stem ; Guinea Pigs ; Hearing ; physiology ; Hearing Tests ; Noise ; Perceptual Masking ; Reaction Time ; Sound ; Vestibular Nuclei ; physiology

Stimulation of the round window (RW) for coupling an implantable hearing system to the cochlea has gained increasing clinical importance. To compare the vibration transfer to the cochlear fluids and partition in response to normal acoustic stimulation and to mechanical stimulation of the RW, we carried out an acoustic-structure coupled finite element analysis using a recently developed finite element (FE) model in our laboratory, which consisted of external ear canal, middle ear and cochlea. Intracochlear pressures were derived during normal forward sound stimulation as well as reverse RW stimulation. A model was utilized to calculate the force required of an actuator at the RW to produce a differential intracochlear pressure that is equivalent to a stimulus produced in normal ear by a given external ear-canal pressure. The current results provided further information to support the optimization of the actuators and adapt existing prostheses for RW stimulation in order to insure sufficient acoustic output.
Acoustic Stimulation ; Cochlea ; physiology ; Cochlear Microphonic Potentials ; physiology ; Ear Canal ; physiology ; Finite Element Analysis ; Hearing Aids ; Humans ; Ossicular Prosthesis ; Pressure ; Round Window, Ear ; physiology ; Vibration

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