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At least 559 records · Page 31Linked to original sources
PubMed1993

Evoked acoustic emissions from the human ear. VI. Findings in cochlear hearing impairment.

Click-evoked otoacoustic emissions (CEOAE) were recorded in 28 subjects with mild to moderate flat or steeply sloping cochlear hearing loss. We used the same equipment and recording technique as previously employed in the testing of newborns. A rescaling and subtraction procedure was implemented in an attempt to eliminate the tail of the stimulus artifact. However, in some cases the method also seems to eliminate a true response. In ears with flat losses and with identified CEOAE, no one had a hearing loss exceeding 40 dB HL in the mid-frequency region (0.5, 1 and 2 kHz). Conversely, in ears with flat losses and without CEOAE, no one had a hearing loss less than 30 dB HL in this frequency region. In ears with sloping hearing losses the thresholds at 1 and 2 kHz were most important for the generation of the CEOAE and a significant correlation between the emission amplitude at 70aud (approximately dB p.e. SPL) and the threshold at 1 kHz was found.

Adolescent↗
PubMed1993

The effect of hearing loss on ABR interpretation: use of a correction factor.

Patients suspected of retrocochlear disorders often have abnormal ABRs in the presence of high-frequency hearing loss, making clinical decisions difficult. In a retrospective study of the ABR test results of 1539 patients, the false-positive and false-negative rates for ABR are presented as a function of hearing loss at 4000 Hz, both before and after using Selters and Brackmann's correction factor for hearing loss. For patients with more than 50 db HL at 4000 Hz the false-positive and false-negative rates, uncorrected for hearing loss, were 25.0% and 2.9% respectively, and when the correction factor was used were 12.5% and 5.8%. When hearing loss at 4000 Hz was over 90 dB the ABR was abnormal in 75% of nontumor patients. Conclusions are that a correction factor for hearing loss is helpful with reservations, and that ABR is not a useful test when 4000 Hz hearing loss is greater than 90 dB HL and 2000 Hz is greater than 75 dB HL.

Adolescent↗
PubMed1998

Use of transient evoked otoacoustic emissions to detect and monitor cochlear damage caused by platinum-containing drugs.

Transient evoked otoacoustic emissions (TEOAE) have been evaluated as a means of monitoring cochlear function in patients receiving the chemotherapeutic agents cisplatin and carboplatin (-cis-diammine, 1,1-cyclobutane dicarboxylate (2) -0,0-platinum). Patients receiving these drugs were monitored prospectively with pure tone audiometry (PTA), tympanometry and TEOAE. Data was collected on 22 subjects receiving cisplatin and nine subjects receiving carboplatin. Significant deterioration in both PTA thresholds and TEOAE energy levels (with no change in tympanometry) were detected in the cisplatin group. No significant deterioration in audiological parameters occurred in the carboplatin group. It is indicated that cisplatin has a significant ototoxic effect in the majority of patients, whereas any ototoxic effect of carboplatin was undetectable. Our findings were different from previous studies in that the measurable changes in TEOAE occurred later than changes in the pure tone audiogram for the cisplatin group.

Acoustic Stimulation↗
PubMed1993

Cochlear damage in guinea pigs following contralateral sound stimulation with and without gentamicin.

The effect of a minimally damaging sound exposure and a sub-ototoxic dose of gentamicin on cochlear hair cells contralateral to the sound exposure was evaluated. The cochleae of pigmented guinea pigs exposed to an 8 kHz pure tone at 116 dB SPL for 1 h and/or 50 mg/kg/day of gentamicin for 10 consecutive days and repeated after an interval of 3 weeks, were used for this purpose. Hair cell loss was found to have occurred in the contralateral cochleae following the sound exposure alone. The occurrence of potentiation, synergism and differential synergism between the agents in the contralateral ears was also seen. Possible explanations for these phenomena are proposed.

Acoustic Stimulation↗
PubMed1993

Wave V latency shifts with age and sex in normals and patients with cochlear hearing loss: development of a predictive model.

In order to study the combined effect of age, sex and cochlear hearing loss on the auditory brainstem response in an adult population, absolute wave V latency measurements were made in 117 ears of 64 patients with cochlear hearing loss and 105 ears of 58 otologically normal control subjects. Among normals, wave V latency was found to increase with age. Latencies in female subjects were significantly shorter than in male subjects. The best predictive model for wave V latency in normals was: wave V latency (ms) = 4.982 + 0.007 x age + 0.091 x sex, where age is measured in years and sex is given a value of 1 for females and 2 for males. In patients with hearing loss, wave V latency increase was determined largely by the degree of hearing loss and the effect of age was moderate. The influence of sex was minimal. Wave V latency in patients with hearing loss was predicted by the formula: wave V latency (ms) = 4.911 + 0.007 x hearing loss + 0.004 x age + 0.081 x sex. These predictive models can be utilized to accurately estimate expected wave V latency in patients with cochlear hearing loss.

Adult↗
PubMed1993

Clinical monitoring using otoacoustic emissions.

Damaging influences to the cochlea are a leading cause of sensorineural hearing loss. Examples include acute or chronic noise exposure and cochleotoxic drugs such as aminoglycosides. Typically, once damage has occurred, the cochlea cannot recover. Therefore, prevention is critical. If damaging influences cannot be avoided, then secondary prevention or early detection of cochlear hearing loss becomes important. Ideally, methods for the detection of cochlear damage should be as specific and as sensitive as possible. Otoacoustic emissions satisfy these criteria and offer a means of testing aspects of cochlear function in a non-invasive and objective way. Evoked otoacoustic emissions measured either after transient stimuli or during two-tone stimulation (distortion-product otoacoustic emissions) are the types most commonly used for clinical purposes. They are stable over time within individual ears and their repeatability has been established under conditions of clinical testing using commercial equipment. Thus, they are well suited as an effective means of monitoring subtle changes in cochlear status. The possibility of making non-invasive repeated measures of cochlear function has led to the widespread use of otoacoustic emissions in animal experiments. Influences of development, anoxia, anaesthesia, noise, and drugs have been monitored. Preliminary studies in humans demonstrate that cochlear damage due to ototoxic drugs such as aminoglycosides or cisplatin and due to noise exposure can be detected using otoacoustic emissions. Comparison of such results to those available using pure-tone audiometry indicates a greater sensitivity of otoacoustic emissions for detecting early cochlear damage.(ABSTRACT TRUNCATED AT 250 WORDS)

Acoustic Stimulation↗
PubMed1993

Otoacoustic emissions and the categorization of cochlear and retro-cochlear lesions.

There are only some cochlear and retro-cochlear lesions that could be detected using a simple measurement of otoacoustic emissions. A simple description of the various lesions that lead to hearing loss and disruption of emissions is presented, a basis for categorizing cochlear and retro-cochlear lesions is discussed, and the types of clinical symptoms likely to be associated with each type of lesion are outlined.

Acoustic Stimulation↗
PubMed1989

Cochleovestibular toxicity related to dichloromethotrexate.

A 69-year-old man receiving monotherapy for lung cancer with dichloromethotrexate (DCM), and without exposure to other chemotherapeutic agents or known ototoxic drugs, developed profound cochleovestibular dysfunction. The initial presentation was vestibular. This resolved, but unilateral hearing loss ensued and continued to progress to a total of 80 db loss in the low frequency range and 40 db in the high range, despite discontinuation of the drug. Because DCM may be used in combination with the known ototoxin cisplatin, the potential of DCM as an ototoxin should also be considered in such patients.

Aged↗
PubMed2006

Ventriculoperitoneal shunt insertion for the treatment of refractory perilymphatic fistula.

OBJECT: The goal of this study was to provide preliminary data regarding clinical and functional outcome, including postoperative morbidity, related to ventriculoperitoneal (VP) shunt insertion for refractory perilymphatic fistula. METHODS: The authors retrospectively reviewed the records of seven consecutive patients who had undergone VP shunt insertion for medically and surgically refractory perilymphatic fistula between 1996 and 2004. Patients were also contacted by telephone and asked to assess retrospectively their symptomatic improvement, changes in functional status, and changes in work status following shunt placement. Preoperative and postoperative functional statuses were assessed using a standardized instrument. In each patient, preoperative opening pressure was measured via lumbar puncture. Pressures ranged from 160 to 300 mm H2O, with a mean of 241 mm H2O. All patients reported significant improvement in symptom severity following surgery. Two patients reported complete resolution of symptoms. Three patients were able to resume full-time work. Clinically significant improvement in functional status was noted in six of seven patients. All patients would recommend the procedure to others in a similar situation. CONCLUSIONS: Data in this study suggest that some patients with disabling vertigo, tinnitus, and headache due to perilymphatic fistula, whose conventional medical and surgical therapies have failed to produce a cure, benefit from VP shunt insertion. The authors hypothesize that VP shunt placement blunts intracranial pressure increases, which would cause secondary elevations in perilymphatic fluid pressure. Shunt insertion reduces perilymph leakage into the middle ear and may permit closure of the fistula.

Aged↗
PubMed2004

Management of the draining ear in children.

There are a variety of causes of otorrhea in children. The most important factor in reaching the proper diagnosis and providing relief of the problem is aural toilet. Once adequate debridement has been performed, the diagnosis is usually clearer, and treatment with ototopicals is significantly more effective. Most cases of otorrhea are due to infection or granulation tissue and can be managed initially with appropriately selected ototopical medication, thereby avoiding the risks and side effects of systemic therapy and the need for referral to a specialist. However, otorrhea in children that is refractory to medical therapy may be due to retained tympanostomy tubes or insidious pathology such as cholesteatoma or malignancy. In such cases, prompt referral to the otolaryngologist can facilitate accurate diagnosis and successful management.

Anti-Bacterial Agents↗
PubMed1993

[Cochlear immune injury following direct antigen challenge to the endolymphatic sac].

Following direct KLH antigen challenge to the endolymphatic sac (e. sac) in guinea pigs, degeneration of the cochlea was examined histologically by light microscopy. Degeneration was seen in 21 out of 140 animals presensitized systemically from day 1 to 5 weeks post secondary KLH challenge to the e. sac. Degeneration of the organ of Corti, stria vascularis and spiral ganglion cells was seen from day 1 in 19, 17 and 7 animals, respectively. There was no increase in these degenerative processes during the time course. In the period from day 1 to day 4, severe bleeding in the perilymphatic space occurred simultaneously with cochlear deterioration. Three animals showed perilymphatic fibrosis which was noted after the first week post KLH secondary challenge. In contrast, animals primarily challenged with KLH (locally administered to the e. sac) showed no cochlear degeneration. These results suggest that a locally mounted immune response in the e. sac can cause direct immune injury to cochlear tissues.

Animals↗
PubMed1995

[Electrocochleographic changes in guinea pigs immunized with type II collagen].

Electrocochleograms (ECoGs) were assessed in guinea pigs with cochlear impairment induced by immunization with type II collagen. Action potential (AP) tuning curves (TCs) were studied using a forward masking technique. Not only AP TCs, but the intensity function of APs and summating potentials (SPs) were assessed. The results were as follows: 1) The TCs displayed the normal pattern in all animals, and the Q10dB values of the curves were within the normal range. 2) Abnormal changes in AP, such as threshold elevation, decrease in amplitude and prolongation of latency were observed. 3) Decreases in +SP were observed in eight of ten animals, but no negative SPs were observed. 4) All animals exhibited degeneration of spiral ganglion cells on light microscopy, despite the preservation of normal hair cells. 5) Levels of antibody against type II collagen were much higher than in controls. This suggests that the normal pattern of TCs may have been the result of only minor hair cell damage. The cause of the decrease in +SP, however, is unknown. Further investigation should be performed to resolve this question. In addition, there may be differences in immune reaction from animal to animal.

Animals↗
PubMed1995

[Measurement of cochlear blood flow during exploratory tympanotomy in patients suspected of having perilymphatic fistulas].

Since impairment of cochlear blood flow is one of the factors implicated in the pathophysiology of sudden deafness, we measured cochlear blood flow in nine patients suspected of having perilymphatic fistulas. All but one patient had sudden sensorineural hearing loss. The exceptional case had experienced rotatory vertigo immediately after nose-blowing. In the eight patients with sudden deafness, the average hearing level ranged from 30dB to 80dB. Among these patients, there was a first reported case of recurrent inner ear barotrauma due to diving. This case was a 41-year-old male who had a second episode of sudden deafness six years after the first sudden deafness episode affecting the same ear. During exploratory tympanotomy, the tip of a laser-Doppler probe was attached to the promontory near the anterior superior portion of the round window niche. The outer diameter of the probe was 1.7mm and the distance between the exciting and receiving optic fibers was 1.0mm. Pulsatory movement of the laser-Doppler output was observed in all 9 patients even after the middle ear mucosa had been removed. We attempted to measure the effects of carbon dioxide on cochlear blood flow, using methods such as inhalation of carbogen and cessation of respiration. In most cases, however, no significant change in cochlear blood flow was observed with these procedures.

Adult↗
PubMedDate not supplied

[Electrophysiological study of cochlear damage in early otosclerosis and after stapedial surgery].

Otoesclerotic patients usually have neurosensorial hearing toss in addition to a predominantly conductive impairment, but there is no universally accepted explanation for this abnormality. The bone conduction threshold in tonal audiometry is accepted as a test of cochlear function. An early evaluation of damage to the cochlea arid acoustic nerve after surgery was made by studying 99 ears with BERA and latency/intensity curves to test cochlear function. We concluded that early damage was present. Postoperative cochlear damage was found in spite of successful surgery, but it was no greater than the damage present before surgery.

Audiometry, Pure-Tone↗
PubMed1999

Supracochlear approach to the petrous apex: case report and anatomic study.

OBJECTIVE: The case of an 11-month old infant with petrous apex abscess drained through the supracochlear air cells prompted an anatomic study of the dimensions of this approach. Of the various approaches to the petrous apex, the supracochlear dissection has been the least described. STUDY DESIGN: Twenty temporal bones were dissected to completely expose the epitympanum. This required mastoidectomy, exenteration of zygomatic root and epitympanic air cells, and removal of the incus. Measurements were taken from three sides of a triangle described by the tegmen tympani (TT), tympanic facial nerve (TFN), and superior semicircular canal (SSCC). Similar measurements were obtained from standard coronal computerized tomographic (CT) scans from a random series of 20 patients. RESULTS: Mean lengths of the sides of the triangle were 7.0 mm (TT), 5.3 mm (TFN), and 4.8 mm (SSCC). The superior petrous apex air cells or marrow space was accessible through the supracochlear exposure in all specimens. Mean lengths from the coronal CT images were 4.2 mm (TT), 3.2 mm (TFN), and 8.45 mm (SSCC). CONCLUSIONS: The authors conclude that the supracochlear approach may provide adequate access to the superior petrous apex for drainage and biopsy in selected cases.

Abscess↗
PubMed1999

Central nervous system impairment in diabetic patients.

The aims of this study were to investigate the function of the central motor control system in interaction with the vestibular and auditory systems (measured by H-reflex changes in response to vestibular and acoustic stimulations) in diabetics without clinical data for CNS impairment, in order to establish whether the disease affects these CNS mechanisms; and to assess this approach in detecting subclinical CNS diabetic pathology. The results show the same mode of change of H-reflex amplitude in response to acoustic and vestibular stimulations in diabetics as in normal subjects. However the degree of facilitation and inhibition was significantly (p < 0.001) higher in diabetics which indicates subclinical CNS dysfunction. Therefore it was concluded that the test is useful in early diagnosis of the diabetic CNS impairment.

Acoustic Stimulation↗
PubMed1999

[Multi-frequency tympanometry in experimentally-induced cochlear lesions in chinchillas and guinea pigs].

OBJECTIVES: To establish that susceptance-conductance tympanograms at a probe-tone frequency of 2 kHz reflects the status of the annular ligament (AL) and through it of the cochlea. METHODS: Experimental study in 5 chinchillas and 22 guinea pigs. Six validating experiments were used: blockages of the stapes and of the round window membrane (RWM), fistula of the RWM, fluid removal from the cochlea, injection of saline in the scala tympani (ST) and acoustic trauma (AT). Quantitative data (mean values of Y226, FR, Y2000, G2000 and B2000) and shape of the curves were analyzed before and immediately after lesions were done. RESULTS: Guinea pig was the most convenient provided bulla was vented and the same tip was used along the experiments. Only the shape of the curves are discriminant: 1/a supplementary sharp peak, centered around negative pressures, is observed in Y/G tympanograms in every case of RWM fistulas and in some case of AT. 2/injection of saline into ST induces immediate and reproducible Y2000, G2000, et B2000 curves modifications. 3/RWM and stapes blockages provoke foreseeable stiffening and sharpening of the tympanograms at 2 kHz. 4/on the contrary, fluid removal from the cochlea induces multiple peaks curves. CONCLUSIONS: Experimentally-induced modifications at the AL either direct (stapes blockage) or indirect by AT or decrease/increase of pressure load at the cochlear interface at the footplate result in noticeable, constant, reproducible changes of curves registered at 2 kHz. The stapes behaves both as the plotter of the curves and the interpreter of the inner ear pressure.

Acoustic Impedance Tests↗