ISSN:0192-9763    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

ObjectiveTo assess the protein and simple sugar content of earwax in pursuit of better ceruminolytic agents.Study DesignCollected earwax specimens were tested in several media for dissolution before being analyzed for amino acid and carbohydrate content.PatientsThe samples were obtained from eight random patients requiring ear plug removal.ResultsThe amino acid composition differs considerably from hair and stratum corneum of glabrous skin. Sugar analysis revealed high levels of galactosamine and galactose.ConclusionsThis analysis of proteins and carbohydrates further characterizes earwax. Future ceruminolytic agents must dissolve lipid, keratin, and a monolayer of lipid covalently bound to the epidermal cells, which encourages cellular aggregation.

ISSN:0192-9763    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

HypothesisCompounds that upregulate mitochondrial function in an aging model will improve hearing and reduce some of the effects of aging.BackgroundReactive oxygen metabolites (ROM) are known products of oxidative metabolism and are continuously generated in vivo. More than 100 human clinical conditions have been associated with ROM, including atherosclerosis, arthritis, autoimmune diseases, cancers, heart disease, cerebrovascular accidents, and aging. The ROM are extremely reactive and cause extensive DNA, cellular, and tissue damage. Specific deletions within the mitochondrial DNA (mtDNA) occur with increasing frequency in age and presbyacusis. These deletions are the result of chronic exposure to ROM. When enough mtDNA damage accrues, the cell becomes bioenergetically deficient. This mechanism is the basis of the mitochondrial clock theory of aging, also known as the membrane hypothesis of aging. Nutritional compounds have been identified that enhance mitochondrial function and reverse several age-related processes. It is the purpose of this article to describe the effects of two mitochondrial metabolites, &agr;-lipoic acid and acetyl l-carnitine, on the preservation of age-related hearing loss.MethodsTwenty-one Fischer rats, aged 24 months, were divided into three groups: acetyl-l-carnitine, &agr;-lipoic acid, and control. The subjects were orally supplemented with either a placebo or one of the two nutritional compounds for 6 weeks. Auditory brainstem response testing was used to obtain baseline and posttreatment hearing thresholds. Cochlear, brain, and skeletal muscle tissues were obtained to assess for mtDNA mutations.ResultsThe control group demonstrated an expected age-associated threshold deterioration of 3 to 7 dB in the 6-week study. The treated subjects experienced a delay in progression of hearing loss. Acetyl-l-carnitine improved auditory thresholds during the same time period (p < 0.05). The mtDNA deletions associated with aging and presbyacusis were reduced in the treated groups in comparison with controls.ConclusionsThese results indicate that in the proposed decline in mitochondrial function with age, senescence may be delayed by treatment with mitochondrial metabolites. Acetyl-l-carnitine and &agr;-lipoic acid reduce age-associated deterioration in auditory sensitivity and improve cochlear function. This effect appears to be related to the mitochondrial metabolite ability to protect and repair age-induced cochlear mtDNA damage, thereby upregulating mitochondrial function and improving energy-producing capabilities.

ISSN:0192-9763    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

ObjectiveTo investigate hearing problems in a sample of elderly Mexican Americans.Study DesignA longitudinal field study of a cohort of 3,050 subjects with in-person baseline and a 2-year follow-up. Population-based, cross-sectional, weighted data were analyzed.Settings and SubjectsHispanic Established Populations for Epidemiologic Studies of the Elderly (H-EPESE) consisting of Mexican Americans aged 65 and older provided basic health data using area probability sampling in five southwestern states during 1993 and 1994.Main Outcome MeasuresInformation was collected regarding demographics, medical conditions, smoking, and alcohol consumption. Hearing problems were identified through a series of self-perceived hearing problem questions, hearing aid use, and inability to hear a normal voice.ResultsA hearing problem was identified in 24.5% of this cohort (weighted, 748/3,049). Statistical analysis using a multiple logistic regression model was performed to identify factors jointly associated with hearing problems. Age group (odds ratio [OR] = 2.7, p < 0.0001), male sex (OR = 1.9, p < 0.0001), hypertension (OR = 1.4, p < 0.001), arthritis (OR = 1.5, p < 0.0005), significant depressive symptomatology (OR = 1.4, p < 0.002), and ever having consumed alcohol (OR = 1.4, p < 0.005) were jointly statistically significantly associated with hearing problems. Number of cigarettes smoked daily (e.g., 0, 1–10, 11–20, etc.) was nearly significantly associated with a hearing problem in the multivariate model (OR = 1.1 for each increased in category, p < 0.07).ConclusionsHearing problems are common in this population. Control of hypertension, an amelioration of arthritis, and decreasing the consumption of alcohol and cigarettes may lower the likelihood of development of a hearing problem. Initial depressive symptomatology may have occurred subsequent to the hearing loss. A longitudinal study would allow determination of the direction of causation.

ISSN:0192-9763    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

ObjectiveEvaluation of the ability of screening high-resolution, nonenhanced, fast spin echo (FSE) T2-weighted magnetic resonance imaging (MRI) of the internal auditory canal (IAC) and cerebellopontine angle (CPA) to detect nonacoustic schwannoma causes of unilateral sensorineural hearing loss (SNHL). FSE-MRI is equally sensitive in detecting acoustic (vestibular) schwannoma as gadolinium-enhanced MRI, but sensitivity to other causes of hearing loss is unknown.Study DesignRetrospective review of screening FSEMRI studies.SettingAcademic otology/neurotology and neuroradiology practices.PatientsThere were 1,070 patients with unilateral SNHL who underwent radiologic screening for retrocochlear pathology.ResultsNormal findings were found in 944 cases. Typical (acoustic) vestibular schwannoma were found in 56 patients. Seventy additional lesions were identified: 27 CPA lesions, 29 inner ear lesions, and 12 intraaxial lesions including 9 infarctions, 1 multiple sclerosis case, 1 mesial temporal lobe sclerosis, and 1 colloid cyst.ConclusionsHigh-resolution T2 FSE-MRI of the IAC and CPA is a highly sensitive screening tool for unilateral SNHL, which can detect a variety of lesions in addition to vestibular schwannomas. To our knowledge in 2 years of follow-up in these patients screened for IAC/CPA lesions, no other lesions causing SNHL have been found. High-resolution FSE screening technique, used in conjunction with appropriate clinical prescreening and referral, can provide an equally sensitive method of evaluating unilateral SNHL compared to gadolinium-enhanced T1 MRI while reducing costs and providing distinct advantages in evaluating nonacoustic schwannoma causes of SNHL.

ISSN:0192-9763    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

ObjectiveTo study nonsyndromic progressive sensorineural hearing impairment in patients with aCOL11A2mutation (DFNA13) in a Dutch kindred.Study DesignSurvey.SettingDepartment of otorhinolaryngology of a university hospital.PatientsTwenty-one living members of a Dutch family (150 relatives in 5 generations; 49 were studied) with autosomal dominant nonsyndromic sensorineural hearing impairment showed linkage to the DFNA13 locus. Mutation analysis revealed a missense mutation in theCOL11A2gene.MethodsHistory was taken, hearing threshold levels were measured in all affected persons, and penetrance was evaluated. Longitudinal analysis (using linear regression analysis of threshold-on-age data) was possible in only 1 case. Cross-sectional analysis comprised the comparison of threshold levels between different generations of the family. Also, hearing thresholds were corrected for median presbyacusis to find out whether the hearing impairment characteristic of this trait is stationary or progressive. Vestibular functions were evaluated with electronystagmography, by use of rotatory and caloric tests.ResultsMost of the affected persons dated their first hearing impairment symptoms to the second to third decade of life. A possibly reduced penetrance was found. Anamnestically, 4 affected persons had hearing impairment symptoms from early childhood onward. Longitudinal analysis in the proband (IV26) revealed the exceptional combination of congenital offset and substantial early progression. Most of the threshold levels differed significantly between the frequencies within each age group and, at the high frequencies (2–8 kHz), between the two age groups covered by generations IV and III (ages 30–38 years and 58–74 years, respectively); the latter could be attributed to presbyacusis. Various caloric abnormalities, including areflexia, were found in about half (8/17) of the tested subjects with sensorineural hearing impairment.ConclusionsCorrection for age, hearing impairment—presumably present and stationary from an early age onward—showed the worst or second-worst threshold usually at 1, 2, and 6 kHz (35–40 dB) or 8 kHz (50 dB), whereas the best or second-best threshold was found at 0.25 to 0.5 and 4 kHz (25 dB). Presbyacusis, presumably from the fourth decade of life onward, caused a change of the typically shaped audiogram described as midfrequency hearing impairment with additional high-frequency impairment.

ISSN:0192-9763    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

ObjectivesTo describe profound hearing loss associated with hydrocodone overuse and the successful rehabilitation of these patients with cochlear implantation.Study DesignRetrospective review.SettingA tertiary otologic referral center.PatientsTwelve patients with rapidly progressive hearing loss and a concurrent history of hydrocodone overuse.InterventionsComprehensive medical histories, physical findings, audiometric tests, and, in those patients undergoing cochlear implantation, postimplantation performance data were reviewed.Main Outcome MeasuresClinical characteristics of hydrocodone-related hearing loss and open set word and sentence performance in those patients undergoing cochlear implantation.ResultsHydrocodone overuse was associated with rapidly progressive sensorineural hearing loss in 12 patients. In four patients the initial presentation was unilateral, and two of the patients experienced vestibular symptoms. None of the 12 patients experienced improved thresholds after high-dose prednisone. Seven of the eight patients undergoing cochlear implantation have demonstrated early success with their devices.ConclusionsHydrocodone is frequently prescribed in combination with acetaminophen for the relief of pain and has a side effects profile similar to other medications in its class. Although not described previously, overuse or abuse can be associated with a rapidly progressive sensorineural hearing loss. These patients can be successfully rehabilitated with cochlear implantation.

ISSN:0192-9763    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

IntroductionThe cochlear ototoxicity of several ear drops is well documented in the literature, but very few studies exist on the vestibular ototoxicity of these topical drugs.Goal of StudyTo develop an animal model for the assessment of the vestibular ototoxicity of ear drops.Materials and MethodsTwo animal groups, consisting of five fat sand rats (FSRs) each, underwent unilateral labyrinthectomy. Normal saline was topically applied into the middle ear cavity of rats in the first group for 7 days (control group). Rats in the second group were treated in the same way by topical gentamicin solution. Cochlear function was assessed by the recording of auditory evoked potential (ABPs) thresholds, and vestibular function was assessed by the recording of vestibular evoked potentials (VsEPs) to angular accelerations.ResultsIn the control group, except for the amplitude of the first wave, there was no significant difference in the VsEPs recorded before and after topical application. In the gentamicin group, VsEPs could not be recorded after 7 days, and ABPs were recorded in one case only, with a threshold of 100 dB sound pressure level (SPL).ConclusionVsEPs seem to be a reliable measure for evaluating the vestibular ototoxicity of topical ear drops.

ISSN:0192-9763    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

ObjectiveFor the surgical treatment of patients with moderate and severe sensorineural hearing loss, the authors have developed a totally implantable hearing device, the totally integrated cochlea amplifier (TICA). To evaluate the effectiveness of transducer and microphone of this device, three separate human studies were conducted.Study DesignThe first study using transducer prototypes involved self experiments in investigators with normal hearing. The second study used the transducer prototypes in patients with hearing loss, and the third study involved the temporary implantation of the final transducer prototype and microphone in patients undergoing otologic surgery.PatientsIn routine middle ear surgery, transducer prototypes were coupled to the ossicular chain of 28 patients. In addition to the transducer, in 5 patients the microphone was placed beneath the skin of the auditory canal, allowing the skin to cover the microphone membrane completely.ResultsThe piezoelectric transducer reached an equivalent sound pressure level of 145 dB SPL ≤10 kHz. The dynamics for music reached 32 dB, which was identical with the results of the preoperative investigations using high-fidelity headsets (33 dB). The low nonlinear distortions of <0.1% and the frequency range of 10 kHz are reflected in the positive evaluation of the sound quality by 84% of the patients involved. When phonetically balanced speech material and music were presented under free field conditions at a sound level of 65 dB SPL, understanding of the phonetically balanced speech material was 100%. Most patients judged the presentations of music as clear and undistorted with all broadband components.ConclusionsData in humans on the performance of the two main components of the TICA implant, the transducer and the microphone, are reported.

ISSN:0192-9763    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

ObjectiveThis study was conducted to evaluate the insertion properties and intracochlear trajectories of three perimodiolar electrode array designs and to compare these designs with the standard Cochlear/Melbourne array.BackgroundAdvantages to be expected of a perimodiolar electrode array include both a reduction in stimulus thresholds and an increase in dynamic range, resulting in a more localized stimulation pattern of the spiral ganglion cells, reduced power consumption, and, therefore, longer speech processor battery life.MethodsThe test arrays were implanted into human temporal bones. Image analysis was performed on a radiograph taken after the insertion. The cochleas were then histologically processed with the electrode array in situ, and the resulting sections were subsequently assessed for position of the electrode array as well as insertion-related intracochlear damage.ResultsAll perimodiolar electrode arrays were inserted deeper and showed trajectories that were generally closer to the modiolus compared with the standard electrode array. However, although the precurved array designs did not show significant insertion trauma, the method of insertion needed improvement. After insertion of the straight electrode array with positioner, signs of severe insertion trauma in the majority of implanted cochleas were found.ConclusionsAlthough it was possible to position the electrode arrays close to the modiolus, none of the three perimodiolar designs investigated fulfilled satisfactorily all three criteria of being easy, safe, and atraumatic to implant.

ISSN:0192-9763    

出版商:OVID    

年代:2000

数据来源: OVID