Cochlear implantation in elderly patients: stability of outcome over time.

BACKGROUND: Cochlear implantation is the standard of care for treating severe to profound hearing loss in all age groups. There is limited data on long-term results in elderly implantees and the effect of ageing on outcomes. This study compared the stability of cochlear implantation outcome in elderly and younger patients. METHODS: A retrospective chart review of cochlear implant patients with a minimum follow up of five years was conducted. RESULTS: The study included 87 patients with a mean follow up of 6.8 years. Of these, 22 patients were older than 70 years at the time of implantation. Hearing in Noise Test scores at one year after implantation were worse in the elderly: 85.3 (aged under 61 years), 80.5 (61-70 years) and 73.6 (aged over 70 years; p = 0.039). The respective scores at the last follow up were 84.8, 85.1 and 76.5 (p = 0.054). Most patients had a stable outcome during follow up. Of the elderly patients, 13.6 per cent improved and none had a reduction in score of more than 20 per cent. Similar to younger patients, elderly patients had improved Short Form 36 Health Survey scores during follow up. CONCLUSION: Cochlear implantation improves both audiometric outcome and quality of life in elderly patients. These benefits are stable over time.

CT grading of otosclerosis.

BACKGROUND AND PURPOSE: The CT grading system for otosclerosis was proposed by Symons and Fanning in 2005. The purpose of this study was to determine if this CT grading system has high interobserver and intraobserver agreement. MATERIALS AND METHODS: All 997 petrous bone CTs performed between December 2000 and September 2007 were reviewed. A total of 81 subjects had CT evidence of otosclerosis on at least 1 side; 68 (84%) had bilateral disease. Because otosclerosis was clinically suspected in both ears of all 81 subjects even if CT evidence was only unilateral, both petrous bones (162 in total) were included. Two blinded neuroradiologists independently graded disease severity using the Symons/Fanning grading system: grade 1, solely fenestral; grade 2, patchy localized cochlear disease (with or without fenestral involvement) to either the basal cochlear turn (grade 2A), or the middle/apical turns (grade 2B), or both the basal turn and the middle/apical turns (grade 2C); and grade 3, diffuse confluent cochlear involvement (with or without fenestral involvement). One reviewer repeat-graded the petrous bone CTs to determine intraobserver agreement with a 7-month intervening delay to mitigate recall bias. RESULTS: There were 154 agreements (95%) comparing the first grading of reviewer 1 with that of reviewer 2 (kappa = 0.93). When the repeat 7-month delayed grading of reviewer 1 was compared with that of reviewer 2, there were 151 (93%) agreements (kappa = 0.90). Therefore, mean interobserver agreement was excellent (mean kappa = 0.92). There were 155 agreements (96%) comparing the original grading of reviewer 1 with the delayed grading (kappa = 0.94), demonstrating excellent intraobserver agreement. CONCLUSIONS: A recently published CT grading for otosclerosis on the basis of location of involvement yielded excellent interobserver and intraobserver agreement.

Cochlear implantation in cochlear otosclerosis.

OBJECTIVES/HYPOTHESIS: The objective was to correlate implant performance in cochlear otosclerosis to 1) matched control samples, 2) severity of otic capsule involvement, 3) prior ipsilateral surgery, and 4) programming issues. STUDY DESIGN: Retrospective case controlled study. METHODS: Study cohort comprised 30 individuals. Diagnosis was based on prior ear surgery (stapedectomy [n = 18] or fenestration [n = 2]) and/or pathognomonic radiological findings. High-resolution computed tomography images of the temporal bones were assessed by two radiologists and graded (range, 0-3) for the extent of otosclerosis. Operative records were reviewed. Performance, programming visits, and the number of electrode deactivations at 6 months and at 1 year after implantation were determined for the individuals with otosclerosis and compared with a group of matched control subjects. A within-group comparison correlating severity of otosclerosis to the above was carried out. RESULTS: Implant performance in individuals with cochlear otosclerosis was not significantly different from those without. Previous surgery on the side of implantation did not alter performance. Programming difficulty as reflected in the number of visits and electrode deactivation for sound quality reasons were comparable. Deactivation for facial nerve stimulation occurred exclusively in otosclerotics with the most severe radiological disease (grade 3) and was only with non-modiolar hugging electrodes (n = 5). There was no observed difference between the radiological extent of otosclerosis and implant performance. CONCLUSION: Individuals with severe otosclerosis considering cochlear implantation can be counseled to expect similar benefit to those without, regardless of whether prior surgery occurred on the side of implantation or of severity of otic capsule involvement. There is a significant risk of facial nerve stimulation in otosclerotics with grade 3 disease.

Does choosing the "worse" ear for cochlear implantation affect outcome?

OBJECTIVE: To determine whether choosing the "better" ear or the "worse" ear for cochlear implantation impacts performance outcome. DESIGN: Retrospective cohort study. SETTING: University teaching hospital-cochlear implant program. METHODS: Two 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. RESULTS: The 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). CONCLUSION: No 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.

Cerebrospinal fluid leak after acoustic neuroma surgery: influence of tumor size and surgical approach on incidence and response to treatment.

OBJECT: The aims of this study were to review the incidence of cerebrospinal fluid (CSF) leakage complicating the removal of acoustic neuroma and to identify factors that influence its occurrence and treatment. METHODS: Prospective information on consecutive patients who underwent operation for acoustic neuroma was supplemented by a retrospective review of the medical records in which patients with CSF leaks complicating tumor removal were identified. This paper represents a continuation of a previously published series and thus compiles the authors' continuous experience over the last 24 years of practice. In 624 cases of acoustic neuroma the authors observed an overall incidence of 10.7% for CSF leak. The rate of leakage was significantly lower in the last 9 years compared with the first 15, most likely because of the abandonment of the combined translabyrinthine (TL)-middle fossa exposure. There was no difference in the leakage rate between TL and retrosigmoid (RS) approaches, although there were differences in the site of the leak (wound leaks occurred more frequently after a TL and otorrhea after an RS approach, respectively). Tumor size (maximum extracanalicular diameter) had a significant effect on the leakage rate overall and for RS but not for TL procedures. The majority of leaks ceased with nonsurgical treatments (18% with expectant management and 49% with lumbar CSF drainage). However, TL leaks (especially rhinorrhea) required surgical repair significantly more often than RS leaks. This has not been reported previously. CONCLUSIONS: The rate of CSF leakage after TL and RS procedures has remained stable. Factors influencing its occurrence include tumor size but not surgical approach. The TL-related leaks had a significantly higher surgical repair rate than RS-related leaks, an additional factor to consider when choosing an approach. The problem of CSF leakage becomes increasingly important as nonsurgical treatments for acoustic neuroma are developed.

Intratympanic gentamicin for the treatment of unilateral Meniere's disease.

OBJECTIVE: To determine the efficacy of intratympanic gentamicin instillation as treatment of incapacitating unilateral Meniere's disease, using a predetermined regimen with a fixed dose. STUDY DESIGN: A prospective study from a single institution between 1988 and 1998. METHODS: One hundred fourteen patients were enrolled in this study. Gentamicin (26.7 mg/mL) was administered three times daily for 4 consecutive days. The Committee on Hearing and Equilibrium Guidelines for Reporting Treatment Results in Meniere's Disease of the American Academy of Otolaryngology and Head and Neck Surgery (1985) were used. RESULTS: Comprehensive data were available for 90 individuals. Complete control of vertigo was achieved in 76 (84.4%), substantial control in 8 (9.0%), limited control in 2 (2.2%), and insignificant control in 4 (4.4%) patients. Disability scores at the end of 2 years were as follows: 76 patients (84.4%) had no disability, 5 (5.6%) had mild disability, 2 (22%) had moderate disability, and 7(7.8%) had severe disability. Caloric testing responses, as determined using electronystagmography, were as follows: 71% of the patients had an absent ice-water response, 16% had a positive ice-water response, and in 13% there continued to be present a bithermal response. Hearing was worse in 22 patients (25.6%), unchanged in 41 (48.2%), and improved in 22 (25.6%). CONCLUSIONS: Intratympanic gentamicin administration using this particular protocol is an effective treatment option for patients with disabling unilateral Meniere's disease. Hearing loss is a distinct possibility, and patients should be advised accordingly.

Electrocochleography and gentamicin therapy for Ménière's disease: a preliminary report.

OBJECTIVE: It is widely held that an enlarged summating potential (SP) relative to the eighth nerve action potential (AP) is a reflection of endolymphatic hydrops. Aminoglycosides are an accepted treatment for incapacitating Ménière's disease and are known to affect both sensory and secretory cells of the inner ear. The intent of this study was to determine whether this effect on secretory cells could be objectively confirmed by virtue of changes in the electrocochleogram (ECoG) of patients receiving gentamicin therapy for Ménière's disease. STUDY DESIGN: This was a prospective longitudinal study of repeated ECoG measures in three groups of subjects. Ménière's patients undergoing gentamicin treatment were compared with two control groups: individuals with stable Ménière's disease and normal-hearing control subjects. SETTING: The study was conducted at a tertiary referral center. PATIENTS: The sample included 21 normal-hearing subjects, 15 patients with stable unilateral Ménière's disease, and 12 with disabling unilateral Ménière's disease. INTERVENTIONS: For patients with disabling Ménière's disease, gentamicin was administered transtympanically. Audiograms, impedance tests, and ECoG were performed twice for all subjects. MAIN OUTCOME MEASURES: The SP and AP amplitudes, AP latency, and SP/AP ratio of the EcoG were measured. RESULTS: A statistically significant reduction in the SP/AP ratio was observed after gentamicin administration (analysis of variance interaction effect: F2 = 5.64; p = 0.0065). CONCLUSIONS: The significant reduction in the SP/AP ratio in the gentamicin-treated Ménière's group supports the hypothesis that gentamicin improves the electrophysiologic function of the cochlea, possibly by reducing the severity of the associated endolymphatic hydrops.

Facial nerve grading systems.

Clinicians require a reliable and sensitive facial grading system to determine the status of facial nerve function postinjury as well as to evaluate the efficacy of treatment outcomes. The method of assessment should be easy to administer, reproducible, clinically relevant, and require little time and expense. The grading system should be sufficiently sensitive to detect changes over time or following treatment. The lack of a universally accepted grading system frequently does not allow meaningful comparison when assessing the effectiveness of treatment protocols for facial nerve injury. The aim of this article is to review most of the previously published facial grading systems. It is our contention that a grading system developed and currently used within our institution appropriately addresses the needs as well as many of the deficiencies of most other grading systems.

Depth and quality of electrode insertion: a radiologic and pitch scaling assessment of two cochlear implant systems.

OBJECTIVE: To compare the depth of electrode insertion in two types of cochlear implants, and to assess the ability of the implantees in each group to place-pitch during random electrical stimulation. STUDY DESIGN: This was a prospective clinical study. SETTING: This study was performed at an implant program within a university teaching hospital. PATIENTS: Five consecutive patients with the Clarion (Advanced Bionics, Symlar, CA, U.S.A.) device and 5 with the Nucleus-22 (Cochlear Corporation, Sydney, Australia) implants were enrolled. All 10 implantees had fully active and functioning electrodes. INTERVENTIONS: The depth of insertion was determined using plain anteroposterior skull film and high resolution computed tomography (CT). The quality of electrode insertion was assessed by pitch scaling; electrodes were randomly stimulated to generate subjective pitch responses. OUTCOME MEASURES: The depth of electrode insertion was measured radiographically as degrees of angular rotation within the cochlea. For pitch scaling, the averaged responses to electrical stimulation was plotted against the "place" of the electrodes along the array. Pitch range, plateauing, and reversal of pitches were also noted. Insertion depth was correlated with the result of pitch scaling and open-set speech discrimination at 3 months. RESULTS: The mean insertion depth was 406 degrees for the Clarion device and 254 degrees for the Nucleus device. CT was used to confirm the intracochlear placement of the electrodes and their relationships to the cochleostomy site. It did not confer more information than the plain films unless kinking had occurred. Pitch perception was consistent with the tonotopic organization of the cochlea. The Nucleus-22 recipients displayed a broader range of pitches with less plateaus and reversals than the Clarion implants. The depth of insertion did not compare well with the outcome of pitch scaling or with open-set speech discrimination scores in either group of implantees. CONCLUSION: The preformed spiral array of the Clarion device allowed deeper electrode insertion compared to the Nucleus-22 device. However, depth of insertion did not translate into better pitch placement.

Hearing preservation in the removal of intracanalicular acoustic neuromas via the retrosigmoid approach.

In a series of 514 consecutive operations for complete excision of acoustic neuromas, 94 procedures were performed via a retrosigmoid approach to preserve the patient's hearing. Twenty-six of these procedures (5.1%) were performed in cases of intracanalicular tumor and 68 (13.2%) were for larger lesions in which most of the tumor was located medial to the porus acusticus within the cerebellopontine angle. Preservation of useful hearing was achieved in 13 (50%) of 26 patients with intracanalicular tumors and in 20 (29%) of 68 with larger tumors. A trend toward higher success rates in intracanalicular tumors appears to be present, although the difference is not statistically significant (p = 0.09). Normal or near normal facial function (House and Brackmann Grades I and II) was present postoperatively in 25 (96%) of 26 patients. Indications for treatment of intracanalicular acoustic neuromas are considered and treatment alternatives are reviewed. Results from other series reporting removal of intracanalicular acoustic neuromas are considered with respect to hearing conservation and postoperative facial nerve function. Surgical excision of intracanalicular acoustic neuromas in otherwise healthy patients appears to be warranted if preservation of useful binaural hearing is considered a worthwhile objective and if perioperative morbidity can be maintained at an acceptably low level. The retrosigmoid approach is familiar to all neurosurgeons and offers a comparable success rate for hearing conservation and probably a superior outcome in terms of facial nerve function when compared with the middle fossa approach.

Prognostic factors in intraoperative facial nerve monitoring for acoustic neuroma.

OBJECTIVES: To determine the predictive value of intraoperative threshold stimulus for facial nerve outcome and the prevalence and prognostic value of persistent trains of activity and frequent spontaneous or mechanically induced contractions during acoustic neuroma surgery. STUDY DESIGN: Prospective recording and subsequent review of facial nerve activity. SETTING: Tertiary referral centre. PATIENTS AND METHODS: Consecutive patients undergoing acoustic neuroma surgery. Intraoperative facial nerve activity was digitised and stored on a personal computer for future analysis. Operative events were flagged. Recordings were available in 27 patients. MAIN OUTCOME MEASURES: Frequent mechanically induced contractions (< 20), prolonged trains of facial nerve activity (total time > 199 seconds), and facial nerve brainstem stimulus threshold were correlated with facial nerve outcome. RESULTS: A brainstem stimulus threshold > 0.1 mA was significantly associated with intermediate or poor facial nerve function (House-Brackmann grade > 2) on the sixth postoperative day, at 1 month and 6 months. Patients with normal or near-normal facial function on the first day and a threshold of > 0.1 mA were significantly more likely to develop a delayed facial nerve palsy. Frequent contractions were noted in 74% of patients and persistent train activity in 59%. Neither was predictive of facial nerve outcome. CONCLUSIONS: An elevated brainstem threshold is helpful in predicting delayed facial nerve palsy and suboptimal facial nerve outcome. Persistent train activity and frequent contractions, do not have major prognostic significance.

Topical gentamicin-induced hearing loss: a mitochondrial ribosomal RNA study of genetic susceptibility.

Mitochondrial ribosomal RNA mutation has been shown to predispose affected individuals to aminoglycoside-induced hearing loss (AIHL). An A-to-G nucleotide substitution at the 1555 position within the 12S ribosomal RNA gene has been identified with a maternally inherited pattern in affected Asian pedigrees. The aim of this study was to identify the frequency of this DNA polymorphism in subjects who appear to show hypersensitivity to topical (middle ear) application of aminoglycoside. In this pilot study, 10 subjects with AIHL were recruited. Eight underwent vestibular ablative therapy with middle ear instillation of gentamicin for disabling vertigo, and two were treated with topical antibiotic drops for otitis media in the presence of a tympanic perforation. DNA samples were extracted, and polymerase chain reaction (PCR) technique was used for gene amplification and purification, searching for 1555 A-to-G substitution in the 12S ribosomal RNA gene. None of the subjects demonstrated this specific mutation.

Development of a sensitive clinical facial grading system.

Clinicians require a reliable and valid method of evaluating facial function after facial nerve injury. This tool should be clinically relevant and easy to administer, provide a quantitative score for reporting purposes, and be sensitive enough to detect clinically important change over time or with treatment. The proposed facial grading system has all essential information, including precise definitions for each item, presented on one page. The facial grading system is based on the evaluation of resting symmetry, degree of voluntary excursion of facial muscles, and degree of synkinesis associated with specified voluntary movement. Different regions of the face are examined separately with the use of five standard expressions. All items are evaluated on point scales, and a cumulative composite score is tabulated. Construct validity was addressed by comparing the proposed facial grading system to prerehabilitation and postrehabilitation treatment scores of 19 patients with varying degrees of facial nerve injury. All patients had documented change in a controlled study of feedback training. The proposed system reports results in a more continuous manner with a wider response range than the House-Brackmann grades. Each component of the grading system is sensitive to change and individually contributes to a change in the composite score. Tests of interrater reliability are currently near completion.

Prognostic indicators of speech recognition performance in adult cochlear implant users: a prospective analysis.

In a previously reported retrospective study of 32 prelingually and postlingually deaf adult Nucleus 22-channel cochlear implant users, multiple parameters were analyzed to determine which were predictive of postimplant speech recognition. Duration of deafness divided by age at implantation, and the psychophysical measures of 1) the threshold slope function (50 to 400 Hz) and 2) detection threshold at 400 Hz obtained preimplantation by means of a round window ball electrode were found to correlate most highly with postimplant performance. A more recent prospective study of 22 consecutive perilingually and postlingually deaf adult Nucleus users has reaffirmed the previous findings. Results revealed a highly significant correlation (r = .873, p < .0001, df = 20) between estimated and realized speech perception. In view of these findings, it would appear that there are variables that can be used preoperatively to predict perilingually and postlingually deaf adults' speech performance. The implications of these findings with respect to patient counseling and realistic expectations both for the patient and the implant team are obvious.

Hearing preservation in acoustic neuroma surgery: value of monitoring cochlear nerve action potentials.

This study reviews the hearing results in 80 consecutive patients who underwent complete removal of histologically proven acoustic neuromas by use of the suboccipital approach. Of these, 56 patients had successful monitoring of cochlear compound action potentials; 20 were not monitored because their surgery predated monitoring; and 4 had unsuccessful monitoring. A significant difference was found in hearing preservation rates between the group in whom compound action potential monitoring was performed and those in whom monitoring was either unavailable or failed (p = 0.02). Overall, 38% (30 of 80) had preserved hearing. There were 51 patients in whom the click threshold for the cochlear compound action potential was measured during surgery. Twenty-one patients had a threshold shift of 20 dB or less, 15 (71%) of these retained serviceable hearing (speech reception threshold < or = 50 dB; speech discrimination score > or = 60%). Of 12 patients in whom the threshold shift was 30 to 60 dB, none had serviceable hearing after surgery. The click threshold shift was predictive of a significant postoperative hearing change (p < 0.001).

Electro-oculographic findings pre- and post-cochlear implantation.

Vestibular symptoms following cochlear implantation are relatively rare, in spite of well-documented evidence of a significant surviving vestibular neuron population in profoundly deaf individuals. This report details the electro-oculographic (EOG) findings before and after insertion of the Nucleus 22-channel cochlear implant in 25 adults. These findings are correlated to the clinical course of these patients.

Frequency selectivity in patients with acoustic neuroma.

Frequency selectivity was compared in subjects with hearing loss due to acoustic neuroma and cochlear pathology, and normal listeners. A particular interest was the role of probe tone parameters on the shape of the tuning curve. Psychophysical tuning curves (PTCs) were measured for each of two equal energy 2000-Hz probe tones (10 dB SL/300 msec and 17 dB SL/60 msec), using simultaneous 1/3-octave narrow-band noise maskers centered at 1, 1.25, 1.6, 2.5, 3.15, and 4 kHz. The results showed that the critical masker levels obtained for impaired listeners were significantly greater than those from normal subjects. The slope of the low-frequency limb of the PTC was steeper for normal compared to hearing-impaired listeners but there was no difference due to site of lesion. In all three groups, the critical masker levels obtained with the short probe were significantly greater than those for the long probe, negating the hypothesis that equal energy probes would yield the same outcomes. Tuning in listeners with hearing loss was highly correlated with audiometric threshold but not with tumor size, width of the internal auditory canal, or tumor location within the cerebellopontine angle. The main conclusion was that cochlear and retrocochlear hearing loss are similar with respect to their effect on frequency selectivity.

Prognostic value of round-window psychophysical testing with cochlear-implant candidates.

The preimplant, psychophysical-test results obtained with a single-ball, round-window electrode for 32 peri- or postlingually deafened, adult, Nucleus 22-channel cochlear-implant users were analyzed and correlated with their postimplant, open-set, speech recognition performance. The results revealed that some preimplant measures do have value as predictors of speech recognition abilities in this group of subjects. All subjects used the MPEAK speech-coding strategy and had been using their device for at least 6 months. The psychophysical measures that were found to correlate most highly with postimplant performance included the detection threshold at 400 Hz and the threshold slope function from 50 to 400 Hz, with lower values associated with higher speech recognition. To a lesser extent, detection thresholds at 100 and 200 Hz, the dynamic range at 200 and 400 Hz, and the gap detection threshold at 100 Hz correlated with speech performance. As well, duration-of-deafness variables were found to correlate significantly with postimplant performance.