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At least 37 records · Page 2Linked to original sources
PubMed1989

Clinical applications of evoked acoustic emissions: results in normally hearing and hearing-impaired subjects.

Click-evoked otoacoustic emissions were recorded in a group of normally hearing subjects (n = 52 ears) and a group of patients demonstrating several common types of sensorineural hearing loss (n = 85 ears) in order to study the clinical applicability of acoustic emissions. In the normally hearing population, all ears demonstrated acoustic emissions that could be elicited at intensities below the normal subjective threshold for the sequence of clicks (mean, -5.2 dB hearing level [HL]). Sixty-seven percent of the normal ears showed long (greater than 20 ms) click-evoked emissions, and spectral analysis showed a broadband spectral component with several narrowband frequency peaks. In patients with sensorineural hearing loss, the incidence of acoustic emissions decreased and the detection threshold increased linearly with increasing threshold. No emissions were elicited from ears exhibiting subjective click thresholds greater than 35 dB HL. Hearing-impaired ears showed a significantly higher proportion of short duration emissions and a significant reduction in the mean number of narrowband frequency peaks in comparison to the controls. Therefore, acoustic emissions can be used as a reliable technique for objective study of normal micromechanical activity within the cochlea and for detection of subtle changes in cochlear disease. However, they have not been demonstrated to be useful in differentiating cochlear disease.

Acoustic Stimulation↗
PubMed1989

Autoimmune disease and cochlear pathology in the C3H/lpr strain mouse.

The C3H/lpr autoimmune strain mouse is a model for spontaneous systemic lupus erythematosus. Inner ear structure and function were examined during systemic autoimmune disease progression to identify correlated auditory system pathology. Onset of the systemic disease occurred at 2-3 months of age and was characterized by elevated serum immune complexes, cryoglobulins, and antinuclear antibodies. Coincident with the onset of autoimmune disease was degeneration of the stria vascularis. Early edema of the stria occurred in the apex and progressed basalward with duration of the disease. By 10 months of age, stria vascularis area was smaller and auditory brainstem response thresholds were elevated. No degeneration of hair cells was seen at any age, suggesting that the stria vascularis may be the primary anatomic site of autoimmune auditory damage in this mouse model.

Age Factors↗
PubMed2001

Hyperacusis in Williams syndrome.

OBJECTIVE: To define hyperacusis in audiologic parameters and to further elucidate central and peripheral auditory pathways. DESIGN AND SETTING: Theories surrounding hyperacusis have always been highly debated. A group of children with Williams syndrome universally complain of hyperacusis. They have highly reproducible behavioural responses to noise and are thus hampered in their social interactions. Loss of inhibitory modulation to efferent sensory input to the cochlea is thought to be a possible mechanism. METHODS: Nine patients with Williams syndrome received a complete audiologic work-up, including audiogram, speech reception thresholds, acoustic reflexes, impedance, and transient evoked otoacoustic emissions (TEOAEs). MAIN OUTCOME MEASURES: Assessment of the efferent system is done by measuring changes in TEOAEs following stimulation of the contralateral ear. RESULTS: Three patients had high-frequency sensorineural hearing loss (SNHL) and thus, as expected, absent TEOAEs, indicating cochlear damage. Two had normal hearing and normal TEOAEs. However, four patients had normal hearing with absent TEOAEs. CONCLUSIONS: These findings are suggestive of cochlear disease and may, in fact, support the hypothesis of outer hair cell modulation by the ipsilateral medial olivocochlear system. Behavioural aspects of the syndrome make audiologic testing difficult. Thus, the diagnosis of SNHL may be hampered if it truly exists. The data show a preponderance of SNHL in the older age groups of our study population. This either reflects previously missed diagnoses or underlying cochlear disease, which may manifest later in life. Thus, this finding blurs the boundary between loudness recruitment and hyperacusis.

Adolescent↗
PubMedDate not supplied

[The working conditions and health status of miners in Donets Basin coal mines].

Data are reported on working conditions of coal miners considering the main physical (dust, noise, vibration, microclimate) and chemical environmental professional factors and their prognosis up to the year 2005. The authors analyze professional morbidity (pneumoconiosis, dust-induced bronchitis, vibration disease, cochlear neuritis etc.) and diseases with temporary loss of the working capacity invalidity and mortality of miners. The relation between working conditions and health status of miners were analyzed.

Absenteeism↗
PubMed1990

[Acoustic oto-emissions. Clinical uses].

Otoemissions are acoustic signals emitted by the cochlea in response to a short acoustic stimulation (click) that may be recorded with a miniaturized microphone placed within the external auditory canal. They reflect the active mechanisms of the cochlea as they relate to the contractile properties of the outer hair cells, which determine the cochlear properties of sensitivity to and selectivity of frequencies. We have been studying for 5 years the clinical applications of otoemissions in over 500 patients. Otoemissions in 100% of normal ears may be recorded, and the detection threshold is generally 10 dB lower than the psycho-physiological threshold. In pathology, otoemissions present a practical interest in the following applications: objective investigation of perception hearing loss, early screening of cochlear disease consecutive to administration of ototoxic drugs, or sound-induced trauma; exploration of Meniere's disease; study of modifications induced by osmotic substances; diagnosis of retrocochlear disease; quick objective assessment of cochlear function in the newborn and the child.

Acoustic Stimulation↗
PubMedDate not supplied

Diagnosis of cochlear Ménière's disease with electrocochleography.

The existence of cochlear Ménière's disease, once considered a variant of classic Ménière's disease but without vertigo, has been questioned due to lack of objective evidence that endolymphatic hydrops is involved with the disease process. Transtympanic electrocochleography (TT ECoG) has emerged as a useful tool for electrophysiologic monitoring of the inner ear, and is especially valuable in assessing endolymphatic hydrops. A retrospective chart review was performed to identify those patients with a diagnosis consistent with cochlear Ménière's disease in order to determine the presence or absence of endolymphatic hydrops using TT ECoG. A total of 7 patients were identified with at least a 2-year follow-up. Using established norms for the summating potential to action potential ratio with click stimulus, 67% of the ears examined demonstrated values consistent with endolymphatic hydrops. Fluctuating aural pressure and tinnitus were present in all patients and medical therapy of diuretics and salt restriction seemed to stabilize or improve the condition in about 80% of the patients. Theoretical considerations are discussed, and a case history of 1 of the study patients is presented to illustrate a typical example of this variant of Ménière's disease.

Adult↗
PubMed1994

Impaired word recognition in noise by patients with noise-induced cochlear hearing loss: contribution of temporal resolution defect.

Fifteen patients with mild noise-induced cochlear hearing loss reported a selective difficulty in understanding speech in noisy settings. To examine the hypothesis that a temporal resolution defect was responsible for this difficulty, the patients were tested for their recognition of monosyllabic words presented against continuous and interrupted wide-band noise backgrounds, at each of seven signal-to-noise ratios. Their recognition performance was compared with that of normal listeners studied with the same paradigms. By comparison with the controls, the group with cochlear hearing loss showed a significant recognition impairment only for words presented against the interrupted masker. This finding was in keeping with the existence of a temporal resolution defect in cochlear disease, though it need not indicate a stimulus timing defect at the level of individual cochlear neurons.

Adult↗
PubMed2002

Female MRL.MpJ-Fas(lpr) autoimmune mice have greater hearing loss than males.

Although women make up approximately 60-70% of the patients with autoimmune hearing loss, little is known about the impact of gender on this cochlear disease. To explore this relationship of gender and autoimmune inner ear disease, an evaluation was made of cochlear function in male and female autoimmune MRL.MpJ-Fas(lpr) mice. Autoimmune disease and hearing loss onset occur at 3-4 months of age, so mice were tested with auditory brainstem response audiometry at 3, 6, and 9 months of age to identify potential gender differences in thresholds. Sera also were analyzed for differences in the autoimmune factors of immune complexes, anti-nuclear antibodies, and hematocrits. By 9 months of age the surviving mice showed a dramatic gender difference. Female mice had thresholds 25-45 dB higher than males at 4, 8, and 16 kHz, although male thresholds at 32 kHz had risen sufficiently to be statistically similar to those for females. No gender differences were seen in any of the systemic autoimmune factors. These findings of worse hearing in female autoimmune mice parallel a reported female preponderance in clinical immune hearing disorders. This potential gender influence in autoimmune inner ear disease must be better understood for effective evaluation and treatment of this disorder.

Animals↗
PubMed1999

Strial dysfunction in the MRL-Fas mouse.

The MRL-Fas(lpr) mouse, a model of multisystemic autoimmune disease, has been proposed as a potential model of autoimmune inner ear disease. Cochlear pathology, consisting of hydropic degeneration of the stria vascularis, has been documented to occur coincident with the establishment of systemic disease in this animal. Because the cochlear pathology is restricted to the stria, this study was designed to evaluate whether the endocochlear potential (EP) would be diminished in these animals because of a loss in strial Na, K-ATPase. Experimental (MRL-Fas(lpr)) mice, with established systemic disease, had auditory brain stem response thresholds and EPs recorded. MRL-+/+ mice served as controls. Animals were then euthanized, and their cochleas were processed for immunohistologic assay for the alpha1 and beta2 subunits of Na,K-ATPase. Density of staining was evaluated by use of quantitative means with densitometry image analysis of digitized images. MRL-Fas(lpr) mice revealed significant elevations in auditory brain stem response thresholds and reductions in EPs but no reductions in Na,K-ATPase levels, as evidenced by immunohistochemical assay. The reduction of EP likely occurs as a result of cellular degeneration within the stria vascularis and likely results from an abrogation of the strial perilymph/endolymph barrier and not from a reduction in strial Na, K-ATPase levels.

Animals↗
PubMed1980

The acoustic reflex latency test: clinical application.

Acoustic reflex latency is the time interval between onset of an intense auditory stimulus and onset of middle-ear muscle contraction. The hypothesis was proposed that a retrocochlear lesion involving the afferent (VIIIth nerve) portion of the reflex arc should result in a prolongation of the reflex latency. A clinical procedure, the Acoustic Reflex Latency Test (ARLT), its protocol, methods and equipment were developed in order to test this hypothesis clinically. Absolute latency values and interaural latency differences (ILD) were established on 4 populations which included normals, cochlear lesions due to Ménière's disease, cochlear lesions of variable etiology, and 11 cases of surgically confirmed acoustic tumor. Results reveal a dramatic prolongation of latency in the presence of retrocochlear lesions (all tumors). The test was found to be most effective when 1. both ipsilateral and contralateral measurements were made, 2. stimulus frequencies of 100 Hz and 2000 Hz were employed and 3. both Absolute Latency and ILD were considered. The ARLT, while utilizing an indirect method of measurement, is a valid, cost-effective, and simple clinical procedure, yielding relative latency values and requiring only minor modifications of standard impedance equipment. The ARLT appears to have a higher efficiency rate than BERA, while providing comparable diagnostic information at a considerable saving of time, cost and personnel.

Acoustic Impedance Tests↗
PubMed2004

Cochlear degeneration in leigh disease: histopathologic features.

OBJECTIVE: To describe pathologic findings from temporal bones acquired from an infant with Leigh disease. STUDY DESIGN: Retrospective case review. MATERIALS AND METHODS: Temporal bones were taken at autopsy from an 8-month-old infant with Leigh disease. The right temporal bone was studied by microdissection. The middle ear was examined and the inner ear sensory organs dissected for study by light microscopy. The left temporal bone was embedded in celloidin, and sections were cut for microscopic examination. RESULTS: Middle ear structures were normal bilaterally. There was, however, evidence of otitis media in both middle ears, which was more severe on the left side. Inner and outer hair cell loss, patchy degeneration of organ of Corti, and loss of nerve fibers in the osseous spiral lamina were found in the basal and middle turns of both cochleas. Basophilic deposits in the stria vascularis were observed in the apical portion of the left cochlea. CONCLUSIONS: Inner ear sensorineural degeneration may occur in Leigh disease. Possible cochlear dysfunction caused by the degenerative changes needs to be considered in the hearing assessment of patients with Leigh disease.

Autopsy↗
PubMed1995

Composite probability modelling of increasing resolution where diagnostic covariates are unmeasurable for some subjects.

When predictive covariates for a dichotomous outcome dependent variable are undetectable or unmeasurable for some subjects, a fact in itself that may be of considerable prognostic importance, traditionally such subjects' data are dropped from multiple logistic regression analyses. An alternative analytical algorithm is offered here for such situations. First, a series of multiple logistic regressions are applied to the complete data where covariates are initially coded as dichotomous, e.g., detectable or nondetectable. Then, a second series of logistic regressions are fitted for those subjects for whom a covariate is detectable and measurable with the fully resolved measure as the covariate. Ultimately, all individual model-specific predicted probabilities of the outcome for a subject are combined into a single probability through the proposed "Composite Probability Modelling of Increased Resolution" (CPMIR). When such an analysis was applied to discriminate 133 patients with acoustic tumours from a sample of 133 patients with cochlear disease, using a latency measure of the auditory brainstem response evoked potential as the predictive covariate, CPMIR yielded a superior model chi square to any component model, used the full cohort of patients, and produced the largest area under the ROC curve. This algorithm is offered as a general statistical modelling device.

Adult↗
PubMed1995

Chemical synaptic transmission in the cochlea.

The last two decades have witnessed major progress in the understanding of cochlear mechanical functioning, and in the emergence of cochlear neurochemistry and neuropharmacology. Recent models describe active processes within the cochlea that amplify and sharpen the mechanical response to sound. Although it is widely accepted that outer hair cells (OHCs) contribute to these processes, the nature of the medial efferent influence on cochlear mechanics needs further clarification. Acetylcholine (ACh) is the major transmitter released onto OHCs during the stimulation of these efferents. The inhibitory influence of this system is mediated by post- and presynaptic nicontinic and muscarinic receptors and the role of other neuroactive substances [gamma-aminobutyric acid (GABA), calcitonin gene-related peptide (CGRP), adenosine 5'-triphosphate (ATP) or nitric oxide (NO)] remains to be determined. The inner hair cells (IHCs) that transduce the mechanical displacements into neural activity, release glutamate on receptor-activated channels of AMPA, kainate, and NMDA types. This synapse is in turn controlled and/or regulated by the lateral efferents containing a cocktail of neuroactive substances (ACh, GABA, dopamine, enkephalins, dynorphin, CGRP). This glutamatergic nature of the IHCs is responsible for the acute destruction of the nerve endings and subsequently for neuronal death, damage usually described in various cochlear diseases (noise-induced hearing losses, neural presbycusis and certain forms of sudden deafness or peripheral tinnitus). These pathologies also include a regrowth of new dendritic processes by surviving neurons up to IHCs. Understanding the subtle molecular mechanisms which underly the control of neuronal excitability, synaptic plasticity and neuronal death in cochlear function and disease is a very important issue for the development of future therapies.

Adenosine↗
PubMed1996

Decreased auditory function in the C3H/lpr autoimmune disease mouse.

To better understand autoimmune-related inner ear disease, cochlear structure and function were evaluated in the C3H/lpr autoimmune strain mouse, a model for systemic lupus erythematosus. C3H/lpr mice were examined at ages from 2 to 12 months along with age-matched C3H/HeJ controls. Autoimmune disease onset occurred at 3-4 months of age as serum immune complexes, antinuclear antibodies, and spleen weights were significantly elevated. Auditory brainstem response (ABR) audiometry showed normal auditory thresholds in C3H/lpr mice at 4 months of age, but elevated thresholds by 6 months, particularly in the high frequencies. Examination of the cochleas revealed no apparent loss of hair cells or spiral ganglion neurons, even in those mice with 50 dB SPL threshold shifts. However, changes were observed in the stria vascularis, including edematous spaces, enlarged capillaries, and thickened vessel linings. These findings imply that cochlear dysfunction in the autoimmune disease mice is the result of stria vascularis pathology.

Analysis of Variance↗