Biomedical subjects
B J Gantz
Publications and source records attributed to B J Gantz.
Surgical management of Bell's palsy.
OBJECTIVES: Incomplete return of facial motor function and synkinesis continue to be long-term sequelae in some patients with Bell's palsy. The aim of this report is to describe a prospective study in which a well-defined surgical decompression of the facial nerve was performed in a population of patients with Bell's palsy who exhibit the electrophysiologic features associated with poor outcomes. In addition, management issues related to Bell's palsy including herpes simplex virus typel etiology, the natural history, electrodiagnostic testing, and efficacy of surgical strategies are reviewed. STUDY DESIGN AND METHODS: A multicenter prospective clinical trial was designed utilizing electroneurography (ENOG) and voluntary electromyography (EMG) to identify patients with Bell's palsy who would most likely develop poor return of facial function, as suggested by Fisch and Esslen. Patients who displayed electrodiagnostic features of poor outcome, >90% degeneration on ENOG testing and no voluntary motor unit EMG potentials within 14 days of onset of total paralysis, were offered a surgical decompression of the facial nerve through a middle cranial fossa surgical exposure, including the tympanic segment, geniculate ganglion, labyrinthine segment, and meatal foramen. Control subjects were those who displayed similar electrodiagnostic features and time course. RESULTS: Subjects who did not reach 90% degeneration on ENOG within 14 days of paralysis all returned to House-Brackmann grade I (n = 48) or II (n = 6) at 7 months after onset of the paralysis. Control subjects self-selecting not to undergo surgical decompression when >90% degeneration on ENOG and no motor unit potentials on EMG were identified had a 58% chance of developing a poor outcome at 7 months after onset of paralysis (House-Brackmann grade III or IV [n = 19]). A group with similar ENOG and EMG findings undergoing middle fossa facial nerve decompression exhibited House-Brackmann grade I (n = 14) or II (n = 17) in 91% of the cases. An exact permutation test confirmed that the surgical group had a significantly higher proportion of patients with a good outcome (House-Brackmann grade I or II) (P = .0002). CONCLUSION: Electroneurography in combination with voluntary EMG successfully identified patients who will most likely return to normal from those who had a greater chance of long-term sequelae from Bell's palsy. Surgical decompression medial to the geniculate ganglion significantly improves the chances of normal or near-normal return of facial function in the group that has a high probability of a poor result. Surgical decompression must be performed within 2 weeks of onset of total paralysis for it to be effective.
Surgical technique for the CLARION cochlear implant.
This paper describes a technique for implantation of the CLARION Multi-Strategy Cochlear Implant based upon the authors' surgical experience with the device. Although much of the procedure is similar to many commonly performed otologic operations, including implantation of other cochlear prostheses, several device-specific modifications are highlighted. Those modifications include a substantial bony seat, facial recess, and cochleostomy, and the use of an electrode insertion tool.
Sensorineural hearing loss after occlusion of the enlarged vestibular aqueduct.
OBJECTIVE: This study aimed to report the hearing results of endolymphatic sac occlusion in patients with enlarged vestibular aqueduct syndrome. STUDY DESIGN: The study design was a multiinstitutional retrospective case series. SETTING: The study was conducted at tertiary otologic referral centers. PATIENTS: The study included 10 previously unreported patients with progressive sensorineural hearing loss and vestibular aqueducts greater than 1.5 mm in diameter on computerized tomography. INTERVENTION: Occlusion of the enlarged vestibular aqueduct was performed by means of a transmastoid surgical approach. Either intraluminal endolymphatic sac obliteration (five patients) or extraluminal extradural endolymphatic sac obliteration (five patients) was accomplished with temporalis fascia. MAIN OUTCOME MEASURES: The postoperative pure tone average (PTA) and speech discrimination scores were compared with the preoperative levels using conventional audiometry. RESULTS: Nine of 10 patients experienced some degree of sensorineural hearing loss. The median change in PTA was a loss of 21 decibels (dB), and 50% of the patients experienced a sensorineural hearing loss greater than 25 dB. Postoperative change in PTA ranged from +10 dB to -59 dB. The median change in speech discrimination score was a loss of 27.5%. Only one patient had an improvement in both speech discrimination score and pure tone averages after surgery. Patients who underwent extraluminal occlusion had a median PTA loss of 12 dB, and patients who underwent open sac occlusion had a median PTA loss of 34 dB. These were not statistically different. CONCLUSION: In this series of 10 patients, 5 had a greater than 25 dB decrease in hearing after occlusion of the enlarged vestibular aqueduct. Surgical occlusion of the enlarged vestibular aqueduct showed no significant benefit in hearing preservation. The otologic surgeon is alerted to the potential for severe sensiorineural hearing loss after occlusion of the enlarged vestibular aqueduct.
Residual speech recognition and cochlear implant performance: effects of implantation criteria.
OBJECTIVE: This study aimed to determine the effects of preoperative speech reception on postoperative speech recognition with a cochlear implant and to develop a statistical index allowing prediction of postoperative speech recognition before implantation. STUDY DESIGN: The study design was a retrospective case review with statistical modeling. SETTING: The study was conducted at a tertiary referral center with an associated Veteran's Administration hospital. PATIENTS: Postlingually deafened adults with and without residual speech reception participated. INTERVENTION: Cochlear implantation with Cochlear Corporation CI-22 and CI-24 devices was performed. MAIN OUTCOME MEASURES: Monosyllabic word recognition was measured. RESULTS: Duration of deafness and preoperative sentence recognition are both significant predictors of word recognition with a cochlear implant and can account for 80% of the variance in word recognition. CONCLUSIONS: Cochlear implant outcomes are variable but predictable within specific ranges.
Facial nerve grafts: from cerebellopontine angle and beyond.
OBJECTIVES: To review the outcomes from facial nerve cable grafting in a variety of pathologic conditions and to determine the possible causes of poor facial function after facial nerve grafting. STUDY DESIGN: A retrospective review of patients undergoing facial nerve grafts through a neurotologic procedure. SETTING: This study was performed at a university-based tertiary referral center. PATIENTS: All 27 patients undergoing a neurotologic procedure that required a facial nerve graft from 1982 to 1997 were reviewed. Fourteen patients had grafts from the facial nerve stump at the brainstem. INTERVENTIONS: All patients had facial nerve function determined by the senior neurotologist and through use of historical data and photographs. MAIN OUTCOME MEASURE: A facial nerve repair recovery score was developed for facial nerve transection and repair. The House-Brackmann scale was found to be inappropriate for transected and repaired nerves. RESULTS: Facial function was found in 23/25 (92%) patients with at least 8 months follow-up. Statistical analysis revealed no significant correlation between graft length and recovery score. Patients who had the nerve grafted to a site distal to the meatal foramen had a mean outcome that was nearly one grade level better than those with an anastomosis proximal to the meatal foramen (i.e., at the brainstem), but this did not reach statistical significance. CONCLUSIONS: Facial nerve grafting is an effective way of restoring facial motor function. A new facial recovery grading scale is proposed for repaired or grafted facial nerves.
Management of cochlear implant infections.
OBJECTIVE: The aim of this study was to illustrate and discuss management of cochlear implant infections. STUDY DESIGN: The study design was a retrospective case review. SETTING: This study was performed at a tertiary referral center with an associated Veterans Administration Hospital. PATIENTS: Postlingually deafened adults who had revision surgery for delayed cochlear implant infections were included in this study. INTERVENTION: Medical and surgical management of device infection without explantation. MAIN OUTCOME MEASURES: Eradication of infection without loss of speech reception. RESULTS: All four patients were successfully managed without explantation. CONCLUSIONS: Explantation of an infected but functioning multichannel implant is not mandatory in the absence of systemic sepsis.
Speech perception performance in experienced cochlear-implant patients receiving the SPEAK processing strategy in the Nucleus Spectra-22 cochlear implant.
Sixteen experienced cochlear implant patients with a wide range of speech-perception abilities received the SPEAK processing strategy in the Nucleus Spectra-22 cochlear implant. Speech perception was assessed in quiet and in noise with SPEAK and with the patients' previous strategies (for most, Multipeak) at the study onset, as well as after using SPEAK for 6 months. Comparisons were made within and across the two test sessions to elucidate possible learning effects. Patients were also asked to rate the strategies on seven speech recognition and sound quality scales. After 6 months' experience with SPEAK, patients showed significantly improved mean performance on a range of speech recognition measures in quiet and noise. When mean subjective ratings were compared over time there were no significant differences noted between strategies. However, many individuals rated the SPEAK strategy better for two or more of the seven subjective measures. Ratings for "appreciation of music" and "quality of my own voice" in particular were generally higher for SPEAK. Improvements were realized by patients with a wide range of speech perception abilities, including those with little or no open-set speech recognition.
Psychological change over 54 months of cochlear implant use.
OBJECTIVE: To determine the long-term psychological outcome of postlingually deafened adults who received multichannel cochlear implants and to relate the psychological outcome to audiological outcome. DESIGN: Thirty-seven recipients of multichannel cochlear implants who participated in a prospective clinical trial completed psychological assessments before implantation and at regularly scheduled follow-ups through 54 mo of implant use. Standardized measures of affect, social function, and personality were used, and scores on these measures were correlated with asymptotic scores on several audiological measures. RESULTS: Evidence of significant improvement on measures of loneliness, social anxiety, and distress were obtained within a year after implantation and throughout the duration of the follow-up period. For measures of assertiveness and marital satisfaction, improvement was apparent only after long-term implant use. Although favorable changes on the Minnesota Multiphasic Personality Inventory (MMPI) Depression Scale were evidenced only in the initial follow-up period, improvements on the MMPI Paranoia and Social Introversion Scales persisted throughout the 54 mo follow-up. CONCLUSION: Multichannel cochlear implant use is associated with long-term psychological benefit. Correlations between audiological outcome and psychological outcome, however, suggested that the relation between audiological benefit and psychological benefit is not simple.
Preliminary experience with neural response telemetry in the nucleus CI24M cochlear implant.
OBJECTIVE: This study aimed to compare recordings of the electrically evoked whole nerve action potential (EAP) made using the reverse telemetry system of the Nucleus CI24M device with those recorded from individuals who use the Ineraid cochlear implant system. STUDY DESIGN: Data were collected in a prospective fashion from Nucleus CI24M cochlear implant users and compared with retrospective data collected from patients who use the Ineraid device. SETTING: All data were collected at the Department of Otolaryngology-Head and Neck Surgery, University of Iowa Hospitals and Clinics. PATIENTS: Data are reported from 8 patients who use the Nucleus CI24M cochlear implant and 20 patients who use the Ineraid cochlear implant system. INTERVENTIONS: The interventions described in this study were diagnostic in nature. MAIN OUTCOME MEASURES: EAP growth and refractory recovery data are reported. EAP thresholds recorded from patients who use the Nucleus CI24M device also are compared with behavioral thresholds for the stimulus used to evoke the EAP as well as the stimulation levels needed to program the speech processor. RESULTS: EAP morphology, growth, and refractory recovery functions recorded using the Nucleus CI24M reverse telemetry system compared favorably with similar measures recorded from Ineraid cochlear implant users. CONCLUSIONS: Reasonable EAP responses can be recorded using the Nucleus CI24M device. More data are needed to determine whether the information about neural responsiveness available with this device will be clinically useful.
Single-channel to multichannel conversions in adult cochlear implant subjects.
OBJECTIVE: This study aimed to compare open-set speech perception of single-channel with multichannel cochlear implants in the same ear of postlingually deafened adults. STUDY DESIGN: The study design was a retrospective case and literature review. SETTING: The study was conducted at a tertiary referral center with an associated veterans administration hospital. PATIENTS: Postlingually deafened adults with at least 6 months of experience with a single-channel cochlear implant were studied. INTERVENTION: Replacement of a single-channel with a multichannel cochlear implant in the same ear was performed. MAIN OUTCOME MEASURES: Open-set word and sentence perception scores at least 6 months after single-channel implantation and multichannel reimplantation were measured. RESULTS: Six of six patients had substantial improvement in open-set speech recognition after reimplantation of the same ear. CONCLUSIONS: Removal of a functioning single-channel implant and replacement with a multichannel device are appropriate in postlingually deafened adults who desire better speech recognition.
Speech perception by prelingually deaf children using cochlear implants.
In this investigation we measured the performance of 50 prelingually deaf children on several speech perception tests. Children were from 2 to 15 years of age, and some children were tested with as much as 5 years of cochlear implant use. Speech perception tests included the recognition of stress pattern, consonants, vowels, words, and sentences. The audiovisual perception of consonants was also measured. Average results indicated that gains were being made in the perception of stress and words in a closed-set context within 1 year from implantation. The perception of words in an open-set context demonstrated much slower increases over time. Large individual differences were observed. Some preliminary data suggest that children who receive implants before the age of 4 years obtain higher scores, on average, than children who receive implants after the age of 5 years. Some children become part-time users or nonusers of their cochlear implants. The average results from 18 congenitally deaf children were significantly higher than the average results from 12 children with prelingually acquired deafness after 3 years of implant use. Information on vowel and consonant features shows increases in performance after 2 years of cochlear implant use, with the exception of the place feature. For this feature, no changes were observed. Vision-alone testing indicated that lipreading performance increased over time. An audiovisual enhancement provided by the cochlear implant was observed for all features.
Non-Hodgkin's lymphoma of the middle ear cleft.
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Appropriateness of magnetic resonance imaging in sudden sensorineural hearing loss.
Idiopathic sudden sensorineural hearing loss is an enigmatic condition of unknown cause. Although the treatment for sudden sensorineural hearing loss is controversial, the evaluation for a cause should not be. All patients are evaluated with a complete history, physical examination, audiologic examination, and blood draw to evaluate complete blood count, general chemistry screen, thyroid function test results, erythrocyte sedimentation rate, and fluorescent treponemal antibody absorbance. Magnetic resonance imaging with gadolinium contrast is essential in the evaluation of idiopathic sudden sensorineural hearing loss, even if there is a complete response to either treatment or no treatment. During the last year we treated 16 patients for idiopathic sudden sensorineural hearing loss with our protocol of intravenous dextran/Hypaque or oral high-dose steroids. Fifteen patients were evaluated immediately before treatment with a magnetic resonance imaging scan. An additional patient had been treated successfully with high-dose steroids at an outside institution and came in for an evaluation. Of these 16 patients, 3 (18.75%) were found to have significant pathologic conditions on magnetic resonance imaging scan. The patient who had been treated successfully on the outside was noted to have a 5-mm intracanalicular acoustic neuroma, the second patient was found to have a multiple sclerosis lesion at the level of the superior olive, and the third patient, who had had a normal magnetic resonance imaging scan 18 months previously, was now found to have a large 4- to 5-cm meningioma in the cerebellopontine angle. We believe it is essential that all patients with idiopathic sudden sensorineural hearing loss be evaluated at some point during their treatment with a magnetic resonance imaging scan with gadolinium contrast.
Cochlear implant use by prelingually deafened children: the influences of age at implant and length of device use.
This study focused on long-term speech perception performances of 34 prelingually deafened children who received multichannel cochlear implants manufactured by Cochlear Corporation. The children were grouped by the age at which they received cochlear implants and were characterized by the amount of time they used their device per day. A variety of speech perception tests were administered to the children at annual intervals following the connection of the external implant hardware. No significant differences in performance are evident for children implanted before age 5 compared to children implanted after age 5 on closed-set tests of speech perception ability. All children demonstrated an improvement in performance compared to the pre-operative condition. Open-set word recognition performance is significantly better for children implanted before age 5 compared to children implanted after age 5 at the 36-month test interval and the 48-month test interval. User status, defined by the amount of daily use of the implant, significantly affects all measures of speech perception performance except pattern perception.
Performance over time of adult patients using the Ineraid or nucleus cochlear implant.
This study examined the average and individual performance over time of 49 adult cochlear implant subjects. Subjects were randomly assigned to receive either the Ineraid cochlear implant, with analog processing, or the Nucleus cochlear implant, with feature-extraction processing. All subjects had postlingual profound bilateral sensorineural hearing loss and received no significant benefit from hearing aids before implantation. Group data were examined in two ways. First, only subjects who had complete data over the test period were examined. Second, an analysis of all available data was carried out by mixed linear-model analysis. In this analysis, to account for missed follow-ups at the planned intervals, data consisting of the observations closest in time to the planned test times were modeled by natural splines with knots at the planned follow-up times. Contrasts between all pairs of planned follow-up times for each device were tested, as were contrasts between devices at each planned follow-up time. Results indicated little difference between the performance of the Ineraid and Nucleus subjects in their level of performance or their rate of learning. Postimplantation performance was typically superior to preimplantation performance within 9 months, and continued to improve up to 18-30 months depending on the speech perception measure. In some subjects, improvements in speech perception measures were observed up to four or five years postimplantation. There was also evidence that three subjects had a decrement in overall speech perception performance, although their postimplantation scores were always higher than their preimplantation scores. In at least one subjects this was likely a result of age-related cognition decrements.
Speech perception in prelingually implanted children after four years.
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Initial comparison between the Clarion, Nucleus and Ineraid cochlear implants.
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