摘要:

ObjectiveTo determine whether choosing the “better” ear or the “worse” ear for cochlear implantation impacts performance outcome.DesignRetrospective cohort study.SettingUniversity teaching hospital–cochlear implant program.MethodsTwo groups of cochlear implantees were selected and matched based on clinical parameters, including duration of deafness/age at implantation, implant types, and processing strategies. Nineteen patients received an implant in his or her “better” ear of the two that had been amplified. An equal number of patients received an implant in the “worse” ear— an ear that was not amplified or was chosen to avoid causing oscillopsia; or if the patient was not willing to relinquish his or her hearing aid in the “better” ear based on subjective or objective criteria. Standard speech perception testing was performed.ResultsThe average open-set speech perception responses at 1 year after implantation were as follows: word recognition score 40.4% and sentence recognition score 81% in the aided subjects (better ears); word recognition score 41.5% and sentence recognition score 84.5% in the unaided group (worse ears).ConclusionNo differences were found between the two groups of implantees. Choosing the “worse” ear for implantation did not appear to have a negative impact on performance outcome in this match-paired study.

ISSN:1531-7129    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

HypothesisThe fact that the anatomy of the basal turn of the human cochlea, especially, is essentially different from that of other species is likely to influence the outcome of cochlear implantation.BackgroundMultichannel cochlear implants give better speech understanding than single-channel devices. They are intended to make use of the tonotopic organization of the cochlea by selectively stimulating subpopulations of the auditory nerve. At higher stimulus levels and with monopolar stimulation, excitation of nerve fibers from other turns may interfere with this concept, especially with modiolus-hugging electrodes.MethodsA three-dimensional spiraling computer model of the human cochlea, based on histologic data, was used to test the spatial selectivity and the dynamic range before cross-turn stimulation takes place for the Clarion HiFocus implant with and without a positioner. The results were compared with a similar model of the guinea pig cochlea.ResultsIn humans (in contrast to the guinea pig), a well-designed modiolus-hugging electrode yielded reduced current thresholds and high spatial selectivity without reduction of the useful dynamic range. The apical turn of the human cochlea, however, is largely comparable in this respect with the guinea pig cochlea, where cross-turn stimulation reduces the dynamic range substantially.ConclusionThe clinical success of cochlear implantation in humans and the favorable results with modiolus-hugging devices depend on the anatomy of the human cochlea.

ISSN:1531-7129    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

HypothesisContralateral suppression of transient evoked otoacoustic emissions (TEOAEs) can be used in a clinical set-up using a procedure based on a unique and robust parameter to quantify the magnitude of suppression for a subject.BackgroundTEOAEs can be suppressed by delivering contralateral white noise (WN). This suppression is thought to be mediated via the efferent nerve fibers that innervate the outer hair cells. The ipsilateral TEOAE-eliciting click stimulus level and the contralateral WN level have a strong impact on the recorded level of suppression.MethodsTEOAEs were recorded using the nonlinear stimulation mode in two conditions (with and without contralateral WN). An optimal TEOAE-eliciting click stimulus level and contralateral WN level were defined to obtain a unique and robust parameter to quantify the magnitude of suppression.ResultsSuppression of TEOAEs with contralateral WN can be measured in a clinical set-up using nonlinear stimulation, and the level of suppression is of the same order of magnitude as measures using the linear stimulation recording mode. The level of suppression appears to be “locked” to the interaural difference between ipsilateral TEOAE-eliciting broadband click stimulus level and the contralateral WN level.ConclusionsA procedure is proposed to record contralateral suppression in a clinical set-up, and normative data are given for a normal-hearing population (n = 60).

ISSN:1531-7129    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

HypothesisThe goal of this investigation was to determine, in patients with sensorineural hearing loss who may show an audiologic alteration in onset overmasking, whether different pathologic conditions differ in this respect, and whether patients with a vestibular neurotomy damaging the cochlear efferents will be affected.BackgroundAuditory detection of brief signals, when presented at the beginning of a simultaneous long masking sound,, may require a higher acoustic level than when presented after several hundred milliseconds. The proposed explanation, in terms of auditory nerve fibers adaptation has been based on the observation of a proportionally smaller increase of firing in response to an amplitude increment at the onset of a stimulus. However, this may not explain all the data, and other underlying processes are certainly involved. The degree or type of sensorineural pathologic condition may be a contributing factor. In addition, the cochlear efferent system, which exhibits a time course and a high-frequency predominance compatible with that of onset overmasking, could be involved.MethodsOnset overmasking of a brief amplitude increment in one pure tone was examined in 6 normal subjects, 12 patients who had undergone vestibular neurotomy, 8 subjects with Ménière's–like symptoms, 5 subjects with presbyacusis, and 3 patients with a small neuroma. Both ears of all subjects were tested. Detection thresholds, amount of onset overmasking, and differences between the two ears were examined.ResultsAll results from subjects with presbyacusis and neuroma were within the range observed in the group of normal subjects. In the group of eight Ménière's syndrome patients, four had results outside the normal range, three had deteriorated detection, and one had better detection. Among the 12 subjects who had undergone neurotomy, 2 had better detection in the unoperated ear.ConclusionsThe results from Ménière's patients indicate that, in addition to the previously reported improved detection threshold for short onset delay, a deterioration of detection thresholds may occur in some subjects. Overall, the results from neurotomized ears do not provide evidence for an involvement of cochlear efferents in this tested psychoacoustic task.

ISSN:1531-7129    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Case ReportSalivary choristoma of the middle ear is a rare entity. The authors report the 26th known case, which is unique in several respects: the patient had abnormalities of the first and second branchial arches, as well as the otic capsule and facial nerve in ways not yet reported. Our patient presented with bilateral preauricular pits, conchal bands, an ipsilateral facial palsy, and bilateral Mondini-type deformities. A review of the literature revealed salivary choristomas of the middle ear to be frequently associated with branchial arch abnormalities, most commonly the second, as well as abnormalities of the facial nerve.Review of the LiteratureAll 25 cases were reviewed and the results reported with respect to clinical presentation, associated abnormalities, operative findings, and hearing results. It has been proposed that choristoma of the middle ear may represent a component of a syndrome along with unilateral hearing loss, abnormalities of the incus and/or stapes, and anomalies of the facial nerve.ConclusionEighty-six percent of the reported patients with choristoma have three or four of the four criteria listed to designate middle ear salivary choristoma as part of a syndrome. In the remaining four patients, all of the structures were not assessed.

ISSN:1531-7129    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

ObjectiveTo study the effect of smoking on patients with vertigo.SettingUniversity hospital.PatientsThirty patients with vertigo who smoke and 30 patients with vertigo who don't smoke were age-, sex-, and diagnosis-matched and given the same medication consecutively for 3 months. Then treatment efficacy was compared between two groups to investigate the relationship between smoking and vertigo.ResultsThe efficacy of treatment of vertigo in the smoking group (30%) was lower than the nonsmoking group (74%). Intractable vertigo is related to smoking behavior but unrelated to either smoking year or tobacco year (exposure to smoking).ConclusionsFor patients with vertigo who smoke during the course of treatment, the treatment may be ineffective. Therefore, neurotologists should inquire about the smoking history in vertigo patients and advise them to abstain from smoking.

ISSN:1531-7129    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

HypothesisThe study was designed to investigate whether endolymphatic pressure exceeds perilymphatic pressure in an endolymphatic hydrops model with a partially functioning endolymphatic sac.BackgroundPrevious investigations of perilymphatic and endolymphatic pressure measurements during endolymphatic hydrops were done in a classic endolymphatic hydrops model, with a surgically blocked endolymphatic duct and sac. This model, in contrast to the clinical situation of Méniére's patients, totally lacks the functional contribution of the endolymphatic sac.MethodsIn the guinea pig, a partially functioning endolymphatic sac was created via dissection of the distal portion of the sac from the sigmoid sinus. Three (n = 5) and 6 months (n = 3) later, perilymphatic and endolymphatic pressures were measured consecutively using a WPI 900A micropressure system.ResultsIt was observed that damage to the distal part of the endolymphatic sac caused endolymphatic hydrops in 58% of the cases. The hydrostatic pressure in hydropic ears did not differ from that of control ears. There was no pressure difference between the perilymphatic and endolymphatic compartments in ears with endolymphatic hydrops. The endocochlear potential in ears with hydrops was statistically significantly decreased (p < 0.002).ConclusionIn a hydrops model developed to be more comparable to the histopathologic appearance of Méniére's disease in the inner ear, no hydrostatic pressure difference was measured between the perilymphatic and endolymphatic spaces. The only functional difference from control ears we found was a decreased endocochlear potential.

ISSN:1531-7129    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

ObjectiveThe age of modern microsurgery has made resection of glomus tumors with extensive skull base involvement possible. Resection of extensive lesions is not without risk of major complication or new cranial nerve deficit. Because glomus tumors are rare and slow growing, data reflecting recurrence risk after resection using modern skull base techniques are lacking. These factors complicate the accurate definition of efficacy of surgical resection and its functional cost. The object of this review is to determine the current incidence of major complications, the surgical cranial nerve deficit, the long-term control rate, and the recurrence risk in patients undergoing surgical resection of glomus jugulare tumors.Study DesignRetrospective case review.SettingPrivate practice tertiary referral center.Patients and InterventionsOne hundred seventy-six patients with glomus tumors underwent 182 lateral skull base resections between 1972 and 1998.Main Outcome MeasuresMajor complications, tumor recurrence, postoperative functional capacity, and factors affecting the incidence of each were assessed.ResultsComplete surgical control was achieved in 85% of cases. There were nine cases of recurrence, for a recurrent rate of 5.5% (9/164). Cerebrospinal fluid leakage occurred in 4.5% of cases with intracranial extension. New deficits for cranial nerves IX, X, XI, and XII occurred in 39%, 25%, 26%, and 21% of cases, respectively. Satisfactory functional recovery was achieved in an overwhelming majority of cases. The mortality rate was 2.7% (5/182).ConclusionsSurgical resection of glomus tumors is established as an effective technique with good functional outcomes and long-term control.

ISSN:1531-7129    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

ObjectiveTo analyze the advantages in safety and precision of biopsies of the petrous apex and petroclival region using open magnetic resonance imaging (MRI).SettingThe University of Leipzig Medical Center.PatientsBiopsies were taken in 13 patients with tumors of the petrous apex and petroclival region.InterventionWith the patient in the 0.5-T intraoperative MRI system (Signa SP; General Electric Medical Systems, Boston, MA, U.S.A.), biopsies were taken from the petrous apex and the petroclival region under imaging control by transseptal, transsphenoidal access. The region of interest was approached with a virtual pointer (Flashpoint Position Encoder; Image Guided Technologies, U.S.A.) and marked with a gadolinium-filled pointer.ResultsIn all patients, the authors obtained enough tissue for histologic study, which also proved to be the suspected tumor. One patient had a bone cyst, another had a malignant lymphoma, and another two a cholesterol granuloma originating from the petrous apex. Three other patients had metastases (carcinoma of the breast, bronchial carcinoma, and unknown origin). Three patients had a meningioma, and another three a chordoma. The authors did not see any postoperative complications.ConclusionsIn the authors' experience, the transsphenoidal access is favorable for approaching and sampling lesions of the petrous apex and the petroclival region. This route, however, is disadvantageous because the course of the internal carotid artery and the brainstem narrow the surgical space to the petrous apex. Open MRI in these cases is very useful because it allows a safe approach to the tumor by navigation and by visualizing the anatomic structures in real-time imaging.

ISSN:1531-7129    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

ObjectiveTo determine if an “observation” protocol with serial scanning is a safe and effective management paradigm for acoustic neuromas in the elderly.Study DesignA retrospective case review was performed.SettingThis study was performed in an academic, tertiary care center.PatientsForty-one patients over the age of 65 years were identified with the primary diagnosis of unilateral acoustic neuroma, without prior treatment or observation.InterventionThe patients were followed with serial, gadolinium-enhanced magnetic resonance imaging (MRI) scans performed at 6 months and then yearly, if no significant growth occurred.Main Outcome MeasuresThe patients were monitored for tumor growth, cranial nerve deficits, and hydrocephalus.ResultsThe patients were followed for an average of 3.5 years (range, 6 months to 9 years). The average tumor size at presentation was 1.14 cm, with a range of growth rates from 0 to 1.2 cm per year. Twenty-one patients demonstrated tumor growth at an average rate of 0.322 cm per year. Only five patients (12%) required further intervention. Three patients underwent translabyrinthine excision, and two patients were treated with radiation. No patients developed significant complications during the observation period.ConclusionsAcoustic neuromas in the older population can be managed safely using serial MRI scanning. No correlation could be made between initial tumor size and subsequent growth rate.

ISSN:1531-7129    

出版商:OVID    

年代:2001

数据来源: OVID