Michel Gersdorff

Preservation of residual hearing with cochlear implantation: how and why.

Conclusions Hearing may be conserved in adults after implantation with the Nucleus Contour Advance perimodiolar electrode array. The degree of hearing preservation and the maximum insertion depth of the electrode array can vary considerably despite a defined surgical protocol. Residual hearing combined with electrical stimulation in the same ear can provide additional benefits even for conventional candidates for cochlear implantation. Objectives We present preliminary results from a prospective multicentre study investigating the conservation of residual hearing after implantation with a standard-length Nucleus Contour Advance perimodiolar electrode array and the benefits of combined electrical and acoustic stimulation. Material and methods The subjects were 12 adult candidates for cochlear implantation recruited according to national selection criteria. A “soft” surgery protocol was defined, as follows: 1–1.2-mm cochleostomy hole anterior and inferior to the round window; Nucleus Contour Advance electrode array inserted using the “Advance-off-stylet” technique; and insertion depth controlled by means of three square marker ribs left outside the cochleostomy hole. These procedures had been shown to reduce insertion forces in temporal bone preparations. Variations in surgical techniques were monitored using a questionnaire. Pure-tone thresholds were measured pre- and postoperatively. Patients who still retained thresholds <90 dB HL for frequencies up to 500 Hz were re-fitted with an in-the-ear (ITE) hearing aid. Word recognition was tested in quiet and sentence perception in noise for the cochlear implant alone and in combination with an ipsilateral hearing aid. Results Hearing threshold level data were available for 12 patients recruited from 6 of the centres. Median increases in hearing threshold levels were 23, 27 and 33 dB for the frequencies 125, 250 and 500 Hz, respectively. These median increases include the data for two patients who had total loss of residual hearing due to difficulties encountered during surgery. “Cochlear view” X-ray images indicated that the depth of insertion varied between 300 and 430°, despite modest variations in the length of the electrode inserted (17–19 mm). The insertion angle had some influence on the preservation of residual hearing at frequencies of 250–500 Hz. Six of the 12 patients retained sufficient hearing for effective use of an ipsilateral ITE hearing aid (≤80 dB HL at 125 and 250 Hz; ≤90 dB HL at 500 Hz). Word recognition scores in quiet were improved from 10% to 30% with the cochlear implant plus ipsilateral hearing aid in 3 patients who had at least 3 months postoperative experience. Signal:noise ratio thresholds for sentence recognition were improved by up to 3 dB. Patients reported that they experienced greatly improved sound quality and preferred to use the two devices together.

Prognostic factors in ossiculoplasty.

Objective: To analyze predictive factors of outcome after ossiculoplasty using a standard ossicular prosthesis system. Study Design: Retrospective review of 140 ossiculoplasties, performed by the same senior surgeon, with titanium prostheses. Settings: Academic hospital and tertiary referral center. Patients: All patients undergoing ossiculoplasty with Spiggle and Theis or Kurz titanium total and partial prostheses. Documented, postoperative follow-up had to be provided. A total of 129 patients (140 ears; 53 men and 76 women) were evaluated. Interventions: These included ossiculoplasties using 75 Spiggle and Theis prostheses (30 partial and 45 total) and 65 Kurz prostheses (35 partial and 30 total). Main Outcome Measures: Mean preoperative and postoperative air-bone gaps and the changes in mean hearing loss were analyzed using a four-frequency (500, 1,000, 2,000, and 3,000 Hz) pure tone average. Success rate was defined as postoperative air-bone gap within 20 dB. A one-way analysis of variance was used to analyze group differences. A multivariate statistical analysis was then undertaken to define the significant factors. Results: There were no statistical difference between the Spiggle and Theis and the Kurz prostheses. Multivariate statistical analysis has identified the predictive value of the presence or absence of the malleus handle and the mucosal status of the middle ear in the prognosis of ossiculoplasties. Conclusion: Anatomical and technical factors diversely affect the functional outcome of tympano-ossiculoplasties. A better knowledge of their predictive value will enable accurate, preoperative, individual assessment when counseling patients with regard to the success of any proposed intervention. The use of these factors will also permit precise matching of future series to allow accurate comparisons.

Macroporous biphasic calcium phosphate efficiency in mastoid cavity obliteration: experimental and clinical findings.

Following our previous experimental studies on the performance of macroporous biphasic calcium phosphate (MBCP) in canine mastoid cavities, we used this material in patients requiring surgical intervention. Twenty-two cases were selected, and in eight specific cases a biopsy specimen was taken. Histologic, ultrastructural, and microanalysis studies were performed. This study demonstrates the effectiveness of MBCP implants as bone graft substitutes for mastoid cavity obliteration. Clinical evaluation of the series and histologic and ultrastructural results demonstrated the bioactivity and osteoconduction of this material, with partial transformation of MBCP granules into lamellar bone after several months.

Inner ear autoantibodies and their targets in patients with autoimmune inner ear diseases.

Immunological mechanisms are thought to play an important role in the pathogenesis of some cochleo-vestibular diseases. This study attempts to present further evidence of autoantibodies reactive against guinea pig inner ear proteins found in patients with autoimmune inner ear diseases (AIED) and specifically identifies the main target antigens of these antibodies. Sera from 110 patients with a clinical diagnosis of either rapidly progressive sensorineural hearing loss (n=32), Ménières disease (n=41), sudden deafness (n=26) or other aetiologies of hearing loss (n

Myelin protein Po as a potential autoantigen in autoimmune inner ear disease.

We have previously shown that a 30,000 Mr protein extracted from guinea pig inner ear tissue is recognized by autoantibodies present in the serum of patients suffering from autoimmune inner ear disease. This protein was localized in the modiolus and in the organ of Corti. We have now identified this protein by a combination of micro‐sequencing and matrix‐assisted laser desorption ionization time‐of‐flight mass spectrometry of its tryptic peptides. A partial sequence of the protein was thereby determined. These data and 2‐dimensional gel electrophoresis followed by immunoblot‐ ting experiments showed that the 30,000 Mr inner ear antigen is the major peripheral myelin protein Po. This suggests that protein Po may be an important autoantigen in autoimmune inner ear disease.—Cao, M. Y., Dupriez, V. J., Rider, M. H., Deggouj, N., Gersdorff, M. C. H., Rousseau, G. G., Tomasi, J.‐P. Myelin protein Po as a potential autoantigen in autoimmune inner ear disease. FASEB J. 10, 1635‐1640(1996)

Tinnitus and otosclerosis

Abstract Fifty patients with otosclerosis and tinnitus were studied for the course of the tinnitus after stapes surgery. Tinnitus disappeared in 64% of the cases, improved in 16%, was unchanged in 14%, and worsened in 6%. The reduction in tinnitus was more favorable after a small fenestra stapedotomy than after a partial stapedectomy with removal of the posterior half of the footplate. An unfavorable postoperative course of tinnitus did not appear to be linked to the postoperative audiometric result. In our study the subjective evaluation of pitch and loudness of the tinnitus did not provide significant information regarding its prognosis.

Guinea pig inner ear antigens: extraction and application to the study of human autoimmune inner ear disease.

In this study, the authors attempted to develop a method of extracting guinea pig inner ear antigens for otoimmunological research, and to investigate the distribution of the antigens in the various structures of the inner ear. The antigens were extracted either from the entire or from various parts of the guinea pig inner ear. These antigens were separated on sodium dodecylsulfate‐polyacrylamide gel electrophoresis (SDS‐PAGE) gels. Western blot techniques were nsed to test sera from patients with inner ear disease against guinea pig inner ear protein extraets. It was found that the various molecular weight antigens in the inner ear were associated with the different structures of the inner ear. The sera of 37.5% N=80) of patients reacted with two bands (30 and 58 kd) of the guinea pig inner ear immunoblots. The 58‐kd band was not specific to the inner ear, but instead was also found in the immunoblots of other guinea pig tissues (brain, lung, and liver). This study suggests that the various antigens of interest could be further extracted and purified from the corresponding locations of the inner ear.

COCH5B2 is a target antigen of anti-inner ear antibodies in autoimmune inner ear diseases.

Objective This study was designed to identify the 58-kDa inner ear protein against which the sera of some patients with idiopathic, progressive sensorineural hearing loss or Ménières disease strongly react. Background We and other groups have previously demonstrated that a 58-kDa protein extracted from guinea pig or bovine inner ear tissue is a target of antibodies in serum samples from some patients with autoimmune inner ear diseases. Methods After separation of inner ear proteins by 10% sodium dodecyl sulfate polyacrylamide gel electrophoresis, the bands corresponding to 58 kDa were localized and excised from the gel. The concentrated protein was then digested with trypsin, and the peptide fragments were separated by high-pressure liquid chromatography. Three fractions were subjected to amino acid sequencing by the classic Edman degradation. Results The sequence of a stretch of 14 amino acids of the first fragment was identical to that of amino acids 526 to 539 of the COCH5B2 protein. The sequences of 11 and 10 amino acids of the second and third fragments, respectively, also were identical to residues 417 to 427 and 396 to 405 of the COCH5B2 protein. These data, together with two-dimensional gel electrophoresis followed by Western blot experiments, confirmed that the 58-kDa inner ear protein is the COCH5B2 protein. Discussion These findings indicate that the 58-kDa target protein of antibodies in serum samples of patients with autoimmune inner ear diseases is the COCH5B2 protein, a molecule that is highly and specifically expressed in the cochlea and vestibule.

Evolution of communication abilities after cochlear implantation in prelingually deaf children

OBJECTIVE This study tries to evaluate different factors on communication ability outcomes in cochlear implanted children. METHODS Communication abilities are studied using the validated APCEI-scale based on five components of the language: cochlear implant acceptance, perceptive language performance, comprehension of the oral orders, expressive language and speech intelligibility. APCEI-scores were calculated every 6 months for the first 2 years, then yearly. The studied variables were: gender, social origin, preoperative residual hearing, age, aetiology of hearing loss, and associated disabilities. RESULTS Communication ability scores increased with high socioeconomic level, presence of residual hearing, younger patients when no residual hearing, connexin mutation related deafness, and absence of associated disabilities. No significant difference has been noted between both sexes. CONCLUSION Many different factors influence the evolution of communication abilities of cochlear implanted children. Investigating the cause of hearing loss, presence of associated disabilities and residual hearing before surgery may help to predict outcome and plan appropriate care to those children with negative predictive factors.

Cochlear implantation in patients with Cogan's syndrome: a review of four cases

Cogans syndrome is a rare disorder that is characterized by a rapid onset of bilateral severe sensorineural hearing loss associated with vertigo and tinnitus, ocular involvement (most commonly an interstitial keratitis) and variable systemic symptoms. We review our experience with four cases treated in our department. We describe their symptoms, the evolution of their disease, the diagnosis, and the radiological investigations with computed tomography and/or magnetic resonance imaging. When medical treatment with corticosteroids failed and no benefit could be obtained with hearing aids at each patients end stage, all patients received a cochlear implant with excellent results. The considerations for implantation in these patients are discussed.