Erdheim-Chester Disease Revealed by Central Positional Nystagmus: A Case Report.

Erdheim-Chester disease (ECD) is a rare histiocytic disorder, recently recognized to be neoplastic. The clinical phenotype of the disease is extremely heterogeneous, and depends on the affected organs, with the most frequently reported manifestations being bone pain, diabetes insipidus and neurological disorders including ataxia. In this article, we report on a case of a 48-year-old woman, whose initial symptom of gait instability was isolated. This was associated with positional nystagmus with central features: nystagmus occurring without latency, clinically present with only mild symptoms, and resistant to repositioning maneuvers. The cerebral MRI showed bilateral intra-orbital retro-ocular mass lesions surrounding the optic nerves and T2 hyperintensities in the pons and middle cerebellar peduncles. A subsequent CT scan of the chest abdomen and pelvis found a left "hairy kidney", while 18 F-FDG PET-CT imaging disclosed symmetric 18F-FDG avidity predominant at the diametaphyseal half of both femurs. Percutaneous US-guided biopsy of perinephric infiltrates and the kidney showed infiltration by CD68(+), CD1a(-), Langerin(-), PS100(-) foamy histiocytes with BRAF V600E mutation. The combination of the different radiological abnormalities and the result of the biopsy confirmed the diagnosis of ECD. Many clinical and radiological descriptions are available in the literature, but few authors describe vestibulo-ocular abnormalities in patients with ECD. Here, we report on a case of ECD and provide a precise description of the instability related to central positional nystagmus, which led to the diagnosis of ECD.

Early Sentence Recognition in Adult Cochlear Implant Users.

OBJECTIVE: Normal-hearing subjects listening to acoustic simulations of cochlear implants (CI) can obtain sentence recognition scores near 100% in quiet and in 10 dB signal-to-noise ratio (SNR) noise with acute exposure. However, average sentence recognition scores for real CI listeners are generally lower, even after months of experience, and there is a high degree of heterogeneity. Our aim was to identify the relative importance and strength of factors that prevent CI listeners from achieving early, 1-mo scores as high as those for normal-hearing-listener acoustic simulations. DESIGN: Sentence recognition scores (100 words/list, 65 dB SPL) using CI alone were collected for all adult unilateral CI listeners implanted in our center over a 5-yr period. Sentence recognition scores in quiet and in 10 dB SNR 8-talker babble, collected from 1 to 12 mo, were reduced to a single dependent variable, the "initial" score, via logarithmic regression. "Initial" scores equated to an improved estimate of 1-mo scores, and integrated the time to rise above zero score for poorer performing subjects. Demographic, device, and medical data were collected for 118 subjects who met standard CI candidacy criteria. Computed tomography of the electrode array allowing determination of the insertion depth as an angle, and the presence or absence of scala dislocation was available for 96 subjects. Predictive factors for initial scores were selected using stepwise multiple linear regression. The relative importance of predictive factors was estimated as partial r with a low bias method, and statistical significance tested with type II analysis of variance. RESULTS: The etiologies chronic otitis and autoimmune disease were associated with lower, widely variable sentence recognition scores in the long-term. More than 60% of CI listeners scored >50/100 in quiet at 1 mo. Congenital hearing loss was associated with significantly lower initial scores in quiet (r 0.23, p < 0.001), as was longer duration of hearing loss (r 0.12, p < 0.001, -0.76 pts per year). Initial scores were negatively correlated with insertion depth (r 0.09, p < 0.001, -0.1 pts per degree), with the highest initial scores being obtained for insertion depths of 300° to 400°. A much greater proportion of scala dislocations was found for perimodiolar arrays compared with straight arrays. Scores were negatively correlated with the proportion of the active electrode array found in scala vestibuli for Nucleus perimodiolar devices (r 0.14, p < 0.01, coefficient -25). Similar overall results were obtained for sentence recognition scores in noise (+10 dB SNR). The intercept value for the obtained regression functions indicated that CI listeners with the least limiting factors generally scored ~95/100 in quiet and ~90/100 in noise. In addition, CI listeners with insertion angles as low as 315° to 360° could obtain sentence recognition scores >80/100 even at 1 day after activation. Insertion depths of 360° were estimated to produce frequency-place mismatches of about one octave upward shift. CONCLUSIONS: Patient-related factors etiology and duration of deafness together explained ~40% of the variance in early sentence recognition scores, and electrode position factors ~20%. CI listeners with insertion depths of about one turn obtained the highest early sentence recognition scores in quiet and in noise, and these were comparable with those reported in the literature for normal-hearing subjects listening to 8 to 12 channel vocoder simulations. Differences between device brands were largely explained by differences in insertion depths. This indicates that physiological frequency-place mismatches of about one octave are rapidly accommodated by CI users for understanding sentences, between 1 day to 1 mo postactivation, and that channel efficiency may be significantly poorer for more deeply positioned electrode contacts.

Objective, audiological and quality of life measures with the CI532 slim modiolar electrode.

OBJECTIVES: To report on electrode array measurements for the Nucleus® CI532 Slim Modiolar Electrode device including: ECAP thresholds, electrode impedances, and psychophysical comfort levels, as well as speech perception results pre- and post-operatively and standardized evaluations of quality of life. METHODS: Forty-four subjects were implanted with the CI532. Electrically evoked compound action potential (ECAP) thresholds and impedances were measured using automatic Neural Response Telemetry intra-operatively, at activation and at six months post implant. Pre- and post-operative measures of words in quiet and sentences in noise were made in multiple languages. Quality of life was assessed using The Speech Spatial Qualities questionnaire (SSQ) and Glasgow Benefit Inventory (GBI). RESULTS: Intra-operative ECAP thresholds were recorded successfully from 90% of electrodes tested. ECAP thresholds varied across the array and a post-hoc Dunn's test showed that median thresholds for electrodes E1-E13 were significantly greater than those for E17-E22 (all P < 0.001). Impedances increased significantly between surgery and activation. Speech recognition scores for words in quiet and sentences in noise showed a significant improvement for the group at six months, when using the cochlear implant, compared with pre-operative performance (P < 0.001). There was a significant increase compared to pre-operative ratings for all sections of the SSQ at six months post activation (P < 0.001). The GBI gave scores significantly above zero for the 'general' subscale and total score. CONCLUSION: Objective ECAP and impedance measures for this new electrode array were as expected and similar to results reported for other array types. Speech perception and quality of life improved significantly following implantation. (Registered as NCT02392403 on ClinicalTrials.gov PRS).

Clinical investigation of the Nucleus Slim Modiolar Electrode.

AIMS: The Nucleus CI532 cochlear implant incorporates a new precurved electrode array, i.e., the Slim Modiolar electrode (SME), which is designed to bring electrode contacts close to the medial wall of the cochlea while avoiding trauma due to scalar dislocation or contact with the lateral wall during insertion. The primary aim of this prospective study was to determine the final position of the electrode array in clinical cases as evaluated using flat-panel volume computed tomography. METHODS: Forty-five adult candidates for unilateral cochlear implantation were recruited from 8 centers. Eleven surgeons attended a temporal bone workshop and received further training with a transparent plastic cochlear model just prior to the first surgery. Feedback on the surgical approach and use of the SME was collected via a questionnaire for each case. Computed tomography of the temporal bone was performed postoperatively using flat-panel digital volume tomography or cone beam systems. The primary measure was the final scalar position of the SME (completely in scala tympani or not). Secondly, medial-lateral position and insertion depth were evaluated. RESULTS: Forty-four subjects received a CI532. The SME was located completely in scala tympani for all subjects. Pure round window (44% of the cases), extended round window (22%), and inferior and/or anterior cochleostomy (34%) approaches were successful across surgeons and cases. The SME was generally positioned close to the modiolus. Overinsertion of the array past the first marker tended to push the basal contacts towards the lateral wall and served only to increase the insertion depth of the first electrode contact without increasing the insertion depth of the most apical electrode. Complications were limited to tip fold-overs encountered in 2 subjects; both were attributed to surgical error, with both reimplanted successfully. CONCLUSIONS: The new Nucleus CI532 cochlear implant with SME achieved the design goal of producing little or no trauma as indicated by consistent scala tympani placement. Surgeons should be carefully trained to use the new deployment method such that tip fold-overs and over insertion may be avoided.

Scalar localization by cone-beam computed tomography of cochlear implant carriers: a comparative study between straight and periomodiolar precurved electrode arrays.

OBJECTIVE: To compare the incidence of dislocation of precurved versus straight flexible cochlear implant electrode arrays using cone-beam computed tomography (CBCT) image analyses. STUDY DESIGN: Consecutive nonrandomized case-comparison study. SETTINGS: Tertiary referral center. PATIENTS: Analyses of patients' CBCT images after cochlear implant surgery. INTERVENTION(S): Precurved and straight flexible electrode arrays from two different manufacturers were implanted. A round window insertion was performed in most cases. Two cases necessitated a cochleostomy. The patients' CBCT images were reconstructed in the coronal oblique, sagittal oblique, and axial oblique section. MAIN OUTCOME MEASURES: The insertion depth angle and the incidence of dislocation from the scala tympani to the scala vestibuli were determined. RESULTS: The CBCT images and the incidence of dislocation were analyzed in 54 patients (61 electrode arrays). Thirty-one patients were implanted with a precurved perimodiolar electrode array and 30 patients with a straight flexible electrode array. A total of nine (15%) scalar dislocations were observed in both groups. Eight (26%) scalar dislocations were observed in the precurved array group and one (3%) in the straight array group. Dislocation occurred at an insertion depth angle between 170 and 190 degrees in the precurved array group and at approximately 370 degrees in the straight array group. CONCLUSION: With precurved arrays, dislocation usually occurs in the ascending part of the basal turn of the cochlea. With straight flexible electrode arrays, the incidence of dislocation was lower, and it seems that straight flexible arrays have a higher chance of a confined position within the scala tympani than perimodiolar precurved arrays.

Decisive criteria between stapedotomy and cochlear implantation in patients with far advanced otosclerosis.

OBJECTIVES: To describe the hearing outcomes in patients with far-advanced otosclerosis and to identify the best initial approach based on preoperative word recognition scores (WRS), pure tone averages (PTA), and radiological classification. STUDY DESIGN: Retrospective case review. SETTING: Academic neurotology tertiary referral center. PATIENTS: All patients (n = 58) with preoperative air conduction PTA less than 85 dB (HL), disyllabic WRS less than or equal to 50% at 60 dB (HL) with well-fitted hearing aids, and evidence of otosclerosis on CT scan, treated in our department over the past 20 years. INTERVENTIONS: Stapedotomy, cochlear implantation, or both. MAIN OUTCOME MEASURES: Postoperative WRS after a minimum of 12 months' follow-up, percentage of patients with WRS greater than 50%. Reliability of air and bone conduction PTAs and WRS in predicting failure of stapedotomy. RESULTS: Fifty-eight patients were divided into three groups: group I, primary stapedotomy (n = 32); group II, primary cochlear implantation (n = 9); and group III, secondary cochlear implantation (with a previous history of stapedotomy) (n = 25). The mean postoperative WRS were 50.6% (± 34), 75% (± 17), and 72% (± 20), respectively. Sixty percent of patients in the stapedotomy group had a postoperative WRS greater than 50% requiring no further treatment, compared to 85% for cochlear implant recipients. No specific predictive factors for stapedotomy outcome could be identified. Surgical difficulties during cochlear implantation were significantly higher in patients with advanced radiological stage. CONCLUSION: Although cochlear implantation gives better overall results, stapedotomy with hearing aids can still be very effective in the management of patients with far-advanced otosclerosis. It should therefore be proposed as a first-line treatment.

Reliability of cone beam computed tomography in scalar localization of the electrode array: a radio histological study.

Postoperative imaging plays a growing role in clinical studies concerning prognostic factors in cochlear implantation. Indeed, intracochlear position of the cochlear implant has recently been identified as a contributor in functional outcomes and radiological tools must be accurate enough to determine the final placement of the electrode array. The aim of our study was to validate cone beam computed tomography as a reliable technique for scalar localization of the electrode array. We performed therefore a temporal bone study on ten specimens that were implanted with a perimodiolar implant prototype. Cone beam reconstructions were performed and images were analyzed by two physicians both experienced in cochlear implant imaging, who determined the scalar localization of the implant. Temporal bones then underwent histological control to document this scalar localization and hypothetical intracochlear lesions. In four cases, a dislocation from scala tympani to scala vestibuli was suspected on cone beam reconstructions of the ascending part of the basal turn. In three of these four specimens, dislocation in pars ascendens was confirmed histologically. In the remaining temporal bone, histological analysis revealed an elevation with rupture of the basilar membrane. Histological assessment revealed spiral ligament tearing in another bone. We conclude that cone beam is a reliable tool to assess scalar localization of the selectrode array and may be used in future clinical studies.

Cochlear implantation feasibility in rhesus macaque monkey: anatomic and radiologic results.

BACKGROUND: Large animal models of implantable hearing devices are needed to assess innovative technologies before using them in humans. The rhesus macaque has cognitive abilities close to humans and has been used in the past but with noncommercial implants or no detailed radiologic descriptions of the surgical procedures. The aim of this study was to evaluate the feasibility of cochlear implantation in this animal model. METHODS: We present detailed radiologic data (CT scan and Cone beam computed tomography) from 7 heads of rhesus macaque monkeys coming from autopsy materials. Several comparative measurements were performed with 10 human temporal bones to emphasize similarities and differences between the macaque and the human inner ear. The radiologic analyses helped planning the surgical approach for cochlear implant insertion in the macaque. RESULTS: We managed to perform one full (720 degrees) and 3 partial insertions (190-330 degrees) of cochlear implants in 4 rhesus macaque cochleae, documented by cone beam computed tomography reconstructions. We confirm that the procedure is facilitated in this animal because the cochlea dimensions are close to humans. However, marked differences in the orientation of the external auditory canal and the basal turn must be taken into account. We suggest that the removal of the inferior wall of tympanal bone provides the optimal axis for electrode array insertion. CONCLUSION: The rhesus macaque monkey is a valid and close-to-human animal model for cochlear implants insertion. Because this species is widely used in both behavioral and physiologic studies, we expect that functional implants can be coupled with electrophysiologic recordings to study the mechanisms of auditory compensation.

Correlations between CT scan findings and hearing thresholds in otosclerosis.

CONCLUSION: High-resolution computed tomography (CT) scan may reveal an isolated fenestral form of otosclerosis, and an extensive form, which involves multiple foci around the otic capsule. Pre- and postoperative hearing thresholds are poorer in patients with extensive otosclerosis and their chance of overclosure is reduced by 90%. OBJECTIVES: To evaluate the relationship between CT scan extension of otosclerotic foci and hearing thresholds in the operated ear, before and after stapedotomy. METHODS: A preoperative CT scan was performed in 200 patients suspected of having otosclerosis. CT scan findings were categorized as negative, isolated fenestral otosclerosis, and extensive otosclerosis. Preoperative and 2 months postoperative air-conduction (AC) and bone-conduction (BC) thresholds were collected. RESULTS: In the operated ear, 150 CT scans (75%) revealed an isolated fenestral otosclerosis; 35 (17.5%) were classified as extensive otosclerosis. Mean preoperative BC was significantly poorer in extensive otosclerosis (30.3 dB) than in isolated fenestral otosclerosis (24.6 dB). Mean postoperative BC remained lower in extensive otosclerosis (30.3 dB) than in isolated fenestral otosclerosis (21.2 dB). An overclosure greater than 10 dB was found in 20% of isolated fenestral otoscleroses and in 2.85% of extensive otoscleroses (chi-square: 5.5; p = 0.02).

Revision stapes surgery: the "lateralized piston syndrome".

OBJECTIVE: The need for revision stapes surgery has many causes, and among these, we describe a particular displacement of the piston: the "lateralized piston syndrome". The goal of this study is to define criteria and surgical management of this syndrome. STUDY DESIGN: Retrospective study over 13 years. SETTING: Tertiary reference center. PATIENTS: A review of 1,289 consecutive stapes operations revealed 119 revisions (9%) from which 22 cases (18.5%) could be classified under the lateralized piston syndrome. INTERVENTION: Revision stapedotomy. MAIN OUTCOME MEASURES: Medical files, preoperative and postoperative audiograms, computed tomographic scans, and operative reports. RESULTS: The 22 cases presented as a delayed conductive hearing loss in 95.5% of cases. Preoperative computed tomographic scans showed a lateralized piston out of the stapedotomy in 81% of cases and touching the tympanic membrane in 54.5% of cases. Revisions revealed a lateral displacement of the piston out of the entire oval window in 86% of cases, with closure of the stapedotomy in all cases and incus necrosis in 77% of cases. Conventional pistons were fitted in 12 cases. In case of a significantly eroded incus, total prostheses (TORPs) in 6 cases and offset pistons in 4 cases were placed. Air-bone gap (ABG) was closed to within 20 dB in 82% of cases. Air-conduction puretone audiometry improvement was 17.2 dB (standard deviation [SD], 19.2), with a mean postoperative ABG of 16.2 dB (SD, 12.7). Only 1 ear, operated with TORP, had a sensorineural deterioration of 20 dB. With offset pistons, ABG was closed to within 20 dB in 100% of cases with a mean postoperative ABG of 8.8 dB (SD, 7.2). CONCLUSION: The lateralized piston syndrome was found in 18.5% of stapes surgery revisions. Surgical management was effective in correcting the conductive hearing loss. In the event of significant eroded incus, we observed better results with offset pistons than with TORPs.

Reliability of high-resolution CT scan in diagnosis of otosclerosis.

OBJECTIVE: To assess the reliability of high-resolution computed tomographic scan (HRCT scan) for the diagnosis of otosclerosis and to determine its usefulness to predict hearing deterioration and surgical difficulties. STUDY DESIGN: Prospective study. SETTING: Tertiary reference center. PATIENTS: Two hundred nine ears (200 patients) presenting progressive conductive hearing loss with normal tympanic membrane, abnormal stapedial reflex, and scheduled for stapes surgery. The mean age was 47.3 years. INTERVENTION: All patients underwent HRCT scan before surgery (slice thickness of 0.6 to 1 mm). Stapedotomy was performed in 99% of cases. MAIN OUTCOME MEASURES: High-resolution computed tomographic scan results were categorized as positive, doubtful, or negative. We classified a CT scan as positive for otosclerosis when a hypodense focus was seen around the otic capsule. Preoperative and postoperative air- and bone-conduction thresholds were collected. RESULTS: Of 209 HRCT scans, 84.2% were classified positive, 8.6% doubtful, and 7.2% negative. In all patients with positive CT scan, otosclerosis was confirmed in surgery. Among 15 negative cases, we found 4 minor malformations and 1 fracture of the stapes. Footplate incidents (mobilized, floating, or fractured footplate; 5.3%) occurred significantly more frequently when an HRCT scan was negative or doubtful (p = 0.05). Mean preoperative air-bone gap was 27.7 dB (standard deviation, 10). Mean postoperative air-bone gap was within 10 dB in 65% and within 20 dB in 92% of cases. Greater than 10 dB deterioration of bone-conduction thresholds occurred in 2% of cases. Mean preoperative and postoperative bone-conduction thresholds were significantly lower in cases of round window obliteration, pericochlear, or internal auditory canal hypodensities (p < 0.005 and p < 0.0001, respectively). CONCLUSION: In our series, the sensitivity of HRCT scan to otosclerosis was 95.1%. Hypodense otosclerotic foci were mostly localized at the anterior part of footplate. Negative or doubtful cases were associated with the highest incidence of stapes footplate complications. Foci involving otic capsule, internal auditory canal, or round window led to a significantly higher risk of sensorineural hearing loss.

The size of the cochlea and predictions of insertion depth angles for cochlear implant electrodes.

AIMS: To establish normative data on the size of the basal turn of the cochlea using high-resolution computed tomography of the temporal bone in adults and children. To determine whether final insertion depth angle for a perimodiolar cochlear implant electrode varies according to cochlear size. METHODS: Forty-two patients screened for cochlear anomaly using computed tomography were randomly selected from patients with otologic disease. Reconstruction of the full basal turn was performed for both ears using a 1.0-mm layer, minimum intensity projection. The largest distance from the round window to the lateral wall (distance A) and the perpendicular distance (B) were measured. Distances were averaged between ears for each individual. In addition, 15 patients were implanted with the Nucleus 24 Contour Advance electrode array using a linear insertion depth of either 17 mm (n = 9) or 19 mm (n = 6). Postoperative X-rays were analyzed using the method of Xu et al. [Am J Otol 2000;21:49-56] to obtain the insertion depth angles for individual electrodes. RESULTS: Mean distance A was 9.23 mm (SD = 0.53, range 7.9-10.8 mm). Perpendicular distance B was significantly correlated with distance A (r2 = 0.57, p < 0.001). The mean difference in insertion depth angle between the 17 and 19 mm groups was 80 degrees . A statistically significant correlation (r2 = 0.51) was found between distance A and the insertion depth angle for the 17 mm group. CONCLUSIONS: The cochlear size measure distance A was repeatable to within the resolution of the high-resolution computed tomography image data. The basal turn of the normally formed cochlea is variable in size. These variations in size would produce >5.0 mm variation in the length of the lateral wall to the point consistent with an insertion depth angle of 360 degrees . Cochlear size influenced final insertion depth angles obtained for the perimodiolar Nucleus 24 Contour Advance electrode.