Validation of the French-language version of the OTOSPEECH automated scoring software package for speech audiometry.

OBJECTIVES: To validate a novel speech audiometry method using customized self-voice recorded word lists with automated scoring. PATIENTS AND METHODS: The self-voice effect was investigated by comparing results with prerecorded or self-recorded CVC (consonant-vowel-consonant) word lists. Then customized lists of 3-phoneme words were drawn up using the OTOSPEECH software package, and their scores were compared to those for reference lists. Finally, the customized list scores were compared on automated (Dynamic Time Warping [DTW]) versus manual scoring. RESULTS: Self-voice did not change scores for perception of CVC words at 10, 20 and 30 dB (ANOVA>0.05). Scores obtained with pre-recorded and self-recorded lists correlated (n=10, R(2)=0.76, P<0.01). Customized list scores correlated strongly with the reference cochlear lists of Lafon in normal-hearing (n=77, R(2)=0.83, P<0.001) and hearing-impaired populations (n=13, R(2)=0.89, P<0.001). Results on the automated and manual scoring methods correlated in both populations (n=77, R(2)=0.71, P<0.01; and n=13, R(2)=0.76, P<0.01, respectively), with DTW scores ranging from 24.17 to 53.24. CONCLUSIONS: Automated scoring of customized self-voice recorded lists for speech audiometry displayed results similar to conventional audiometric techniques.

Fixation of cochlear implants: an evidence-based review of literature.

HYPOTHESIS: There are numerous cochlear implant fixation techniques to prevent soft tissue complications related to device migration. The literature does not provide sufficient evidence to determine the most suitable fixation method. BACKGROUND: Cochlear implants (CI) are becoming a routine treatment for patients with severe to profound deafness. Steadily growing numbers of implant centres and surgeons worldwide are inevitably leading to higher rates of complications, including device migration. It is currently unknown whether this can be prevented by proper implant fixation during surgery. The low prevalence of this complication makes it challenging to interpret publications regarding CI fixation techniques. METHODS: An exhaustive literature review reveals a variety of different fixation techniques. Most authors advocate the creation of a bony well for the CI receiver/stimulator (R/S); however, an increasing number of surgeons no longer secure implants at all. Here we give an overview of all published fixation methods, with special attention to the evidence-based quality and descriptions of the advantages and drawbacks of each. CONCLUSIONS: Literature review reveals an absence of level I evidence-based publications addressing device migration. Existing publications report on too few cases to draw a conclusion on whether surgical fixation prevents implant migration. To have statistical power, studies of alternative or new fixation methods should include high numbers of implantations in each study arm and the studies should be longitudinal and prospective. In default of other evidence, it seems fair to define good practice as the creation of at least a bony well and/or (bony) sutures.

Involvement of T-cell receptor-beta alterations in the development of otosclerosis linked to OTSC2.

Otosclerosis is a common form of hearing loss, characterized by disordered bone remodeling in the otic capsule. Within the otosclerotic foci, several immunocompetent cells and immune-modulating factors can be found. Different etiological theories involving the immune system have been suggested. However, a genetic component is clearly present. In large otosclerosis families, seven autosomal-dominant loci have been found, but none of the disease-causing genes has been identified. This study focused on the exploration of the second otosclerosis locus on chromosome 7q34-36 (OTSC2), holding the T-cell receptor beta locus (TRB locus). A significantly lower T-cell receptor-beta (TCR-beta) mRNA expression and percentage of blood circulating TCR-alphabeta(+) T cells was detected in OTSC2 patients compared with controls and patients with the complex form of the disease. Further analysis illustrated more significant disturbances in specific T-cell subsets, including an increased CD28(null) cell population, suggesting a disturbed T-cell development and ageing in OTSC2 patients. These disturbances could be associated with otosclerotic bone remodeling, given the known effects of immunocompetent cells on bone physiology. These data implicate the TRB locus as the causative gene in the OTSC2 region and represent an important finding in the elucidation of the disease pathology.

Auditory speech sounds evaluation (A(section)E): a new test to assess detection, discrimination and identification in hearing impairment.

This paper describes a set of suprathreshold tests, available as a software package (A(section)E((R))), for the auditory evaluation of the hearing impaired. It uses isolated speech sounds as test material for a discrimination, identification and detection test, and is specifically suited to test preverbal children. All tests allow strict analytical interpretation. The test material and procedures are described. Their clinical use is illustrated. The authors claim that suprathreshold tests are feasible in the preverbal child, allowing analytical evaluation of the auditory capacities. These tests are complementary to the routinely used detection tests and add significantly to the hearing evaluation in preverbal children. The authors recommend the phoneme discrimination test for selection of cochlear implant candidates and for the evaluation and fitting of cochlear implants.

Normative data of the A(section)E discrimination and identification tests in preverbal children.

The A(section)E((R)) is a set of suprathreshold tests for the auditory evaluation of the hearing impaired. A particular population of interest is the hearing-impaired preverbal child. This paper reports on normative data of the A(section)E((R)) discrimination test in children aged 10 months and of the A(section)E((R)) identification tests in children aged 2 to 4 years. Normally hearing children of these ages were tested and pass criteria were defined in such a way that 95% of the hearing infants would pass the tests. With these criteria, the A(section)E((R)) discrimination test is feasible at 10 months of age and the A section signE((R)) identification test from 30 months of age.

[Loss and uncontrolled use of radioactive sources]. / Verlies en ongecontroleerd aanwenden van radioactieve bronnen.

In the course of history, exposure to radioactive sources escaping regular control, has been the main cause of fatal accidents, with the exception of the reactor accident at Chernobyl. After the disintegration of the Soviet Union, numerous lost sources have been found, sometimes with serious physical damage. The attacks of September 11, 2001 have focussed the attention on the possibility of nuclear terrorism. Although the risks of fatal consequences are rather limited, the possible uncontrolled exposure to ionizing radiation has an important psycho-social impact on the population. After a brief survey of the types of radioactive sources for medical and industrial applications and a discussion of the risks and exposure routes, possible scenarios are illustrated by well documented case histories. The main conclusions of this analysis are: Radioactive materials are not unique as a potential threat by toxic materials. The most serious consequences for individuals occur as the result of external radiation, mostly with skin contact with medium-active sources which are relatively easily accessible. The collective impact is mostly psycho-social and is more important for a dispersed contamination of the environment. Many sources are detected via medical complaints. The knowledge of the specific symptoms is consequently very important. A dispersion of radioactive contamination has usually considerable economic consequences. Accidents occur particularly, but certainly not exclusively, in relatively unstable countries. Change of owner or final evacuation of the source constitute a critical phase in many scenarios.

Basic fitting and evaluation parameters of a newly designed cochlear implant electrode.

OBJECTIVE: To validate a newly designed cochlear implant electrode (TRACE) in the standard monopolar mode and compare it to a patient group implanted with a standard Nucleus Contour cochlear implant electrode. The electrode contacts of the TRACE electrode have the same active surface area for stimulation, but the position in the scala tympani is different from that of the Nucleus Contour electrode. MATERIAL AND METHODS: The following parameters, used in cochlear implant fitting and evaluation procedures, were determined: the threshold and comfort stimulation current levels; the electrode impedances; and the phoneme discrimination and speech recognition scores using the ACE speech algorithm. CONCLUSION: The new electrode does not differ significantly from the standard Nucleus Contour electrode in terms of the investigated parameters within the test group.

A genotype-phenotype correlation for GJB2 (connexin 26) deafness.

INTRODUCTION: Mutations in GJB2 are the most common cause of non-syndromic autosomal recessive hearing impairment, ranging from mild to profound. Mutation analysis of this gene is widely available as a genetic diagnostic test. OBJECTIVE: To assess a possible genotype-phenotype correlation for GJB2. DESIGN: Retrospective analysis of audiometric data from people with hearing impairment, segregating two GJB2 mutations. SUBJECTS: Two hundred and seventy seven unrelated patients with hearing impairment who were seen at the ENT departments of local and university hospitals from Italy, Belgium, Spain, and the United States, and who harboured bi-allelic GJB2 mutations. RESULTS: We found that 35delG homozygotes have significantly more hearing impairment, compared with 35delG/non-35delG compound heterozygotes. People with two non-35delG mutations have even less hearing impairment. We observed a similar gradient of hearing impairment when we categorised mutations as inactivating (that is, stop mutations or frame shifts) or non-inactivating (that is, missense mutations). We demonstrated that certain mutation combinations (including the combination of 35delG with the missense mutations L90P, V37I, or the splice-site mutation IVS1+1G>A, and the V37I/V37I genotype) are associated with significantly less hearing impairment compared with 35delG homozygous genotypes. CONCLUSIONS: This study is the first large systematic analysis indicating that the GJB2 genotype has a major impact on the degree of hearing impairment, and identifying mild genotypes. Furthermore, this study shows that it will be possible to refine this correlation and extend it to additional genotypes. These data will be useful in evaluating habilitation options for people with GJB2 related deafness.

Cochlear implants in aplasia and hypoplasia of the cochleovestibular nerve.

OBJECTIVE: To report on the outcome of four patients with aplasia or hypoplasia of the cochleovestibular nerve who have received a cochlear implant. STUDY DESIGN: Retrospective case review. SETTING: Tertiary referral center. PATIENTS: Four patients with: 1) type I aplasia; 2) type IIa aplasia; 3) type IIa hypoplasia; and 4) type IIb aplasia received a cochlear implant. All patients had corner audiograms even with hearing aids. INTERVENTION: Three patients received a LAURA multichannel implant, and one patient received a Nucleus 24 implant. MAIN OUTCOME MEASURE: Auditory performance, educational setting. RESULTS: The patients with type I and type IIb aplasia did not have auditive perception with their implant and became non-users. Both are now in a total communication educational setting. The patients with type IIa aplasia and hypoplasia had moderate audiological results with the implant with audiometrical thresholds of approximately 40-60 dB HL (pure tone average), moderate phoneme discrimination, and poor word discrimination. One child is in a total communication educational setting and the other in an oral educational setting, but the preferred mode of communication remains total communication for both. Both appear to benefit from the implant nonetheless. CONCLUSION: Patients with aplasia/hypoplasia of the cochleovestibular nerve should be counseled with caution with respect to cochlear implantation, but particular circumstances may justify the intervention. At present these circumstances seem to be a type IIa aplasia or hypoplasia in which the end organ (cochlea or common cavity) still connects to a neural structure on MRI.

Middle ear status in ears showing high admittance tympanograms. Clinical value of the use of the two-component 678 Hz oto-admittance tympanogram.

The present paper reports on the results of a retrospective study using 678 Hz susceptance-conductance tympanometry performed on abnormally high admittant middle ears. High admittance was proven to be caused by (partial) disruption or lysis of the ossicular chain. Retrospective analysis shows that 678 Hz tympanometry seems to be more accurate in the differential diagnosis of ossicular chain disruptions compared to CT-imaging of the ossicular chain (88% versus 81% correct identification respectively). Classic tympanometry using a probe frequency of 226 Hz was abnormal in only 43% of the cases.

Otosclerosis: a genetically heterogeneous disease involving at least three different genes.

Otosclerosis is caused by abnormal bone homeostasis of the otic capsule, resulting in hearing impairment in 0.3%-0.4% of the white population. The etiology of the disease remains unclear and environmental as well as genetic factors have been implicated. We localized the first autosomal-dominant locus to chromosome 15 in 1998 (OTSC1) in an Indian family and, recently, we reported the localization of a second gene for otosclerosis to a 16 cM interval on chromosome 7q (OTSC2). In this study, we recruited and analyzed nine additional families (seven Belgian and two Dutch families with 53 affected and 20 unaffected subjects) to investigate the importance of these loci in autosomal-dominant otosclerosis. We completed linkage analysis with three microsatellite markers of chromosome 15 (D15S652, D15S1004, D15S657) and five microsatellite markers of chromosome 7 (D7S495, D7S2560, D7S684, D7S2513, D7S2426). In two families, results compatible with linkage to OTSC2 were found, but in the seven remaining families OTSC1 and OTSC2 were excluded. Heterogeneity testing provided significant evidence for genetic heterogeneity, with an estimated 25% of families linked to OTSC2. These results indicate that, besides OTSC1 and OTSC2, there must be at least one additional otosclerosis locus.

A Two-stage bipodal screening model for universal neonatal hearing screening.

OBJECTIVE: A model is proposed for universal neonatal hearing screening. METHODS: The screening model is two-staged because it consists of a first test and, in case of failure (1.4% of the subjects), of a retest 3 weeks later. It is bipodal because it involves both the hospital audiologic department and a central Well Baby Organization. The idea is to have a maximal number of newborns tested at the maternity by trained audiologists and to have the Well Baby Organization trace and chase the missing subjects. The model has been evaluated during 1 calendar year (1999) in a maternity with 2,012 newborns. RESULT: The result is a coverage of 99.3%. Most newborns (97.3%) were tested at the maternity ward with a total time investment of less than 15 minutes per child. The actual test time is 2 minutes, 12 seconds (median value). The Well Baby Organization keeps track of all the results and has to test no more than 2% of the newborns. Sensitivity and specificity were not the primary outcomes of this evaluation, but they were similar to those of a previous study evaluating the screen procedure on a larger scale, giving a sensitivity of approximately 100% and a false alarm rate of 1/1,000. CONCLUSION: These figures demonstrate that universal neonatal hearing screening is feasible within the existing health care structure, with unprecedented coverage, sensitivity, and specificity.

CT and MR imaging of congential abnormalities of the inner ear and internal auditory canal.

The embryology of the inner ear must be known as many of the inner ear malformations present as a result of the arrest during the various stages of embryology. These malformations are described in this "embryologic" perspective and specific names for certain malformations are no longer used. Both CT and MR can be used to look at inner ear malformations but often both techniques are complementary. However, CT is preferred when associated middle- or external ear malformations must be excluded. Magnetic resonance is preferred when subtle changes in the membranous labyrinth or abnormalities of the nerves in the internal auditory canal must be visualised. The CT and MR technique must however be adapted as more and more subtle congenital malformations can only be seen when the right technique is used. The heavily T2-weighted gradient-echo or fast spin-echo MR techniques are mandatory if malformations of the inner ear must be excluded. The purpose of this paper is to describe the techniques used to study these patients and to give an overview of the most frequent and important congenital malformations which can be found in the inner ear and internal auditory canal/cerebellopontine angle.

Contralateral suppression of transient evoked otoacoustic emissions: normative data for a clinical test set-up.

HYPOTHESIS: Contralateral 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. BACKGROUND: TEOAEs 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. METHODS: TEOAEs 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. RESULTS: Suppression 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. CONCLUSIONS: A procedure is proposed to record contralateral suppression in a clinical set-up, and normative data are given for a normal-hearing population (n = 60).

Neonatal hearing screening with transient evoked otoacoustic emissions--retrospective analysis on performance parameters.

The present paper reports on the implementation of a maternity based neonatal hearing-screening program in a private hospital. A retrospective analysis is performed on the test pass rate, the coverage and the number of children that become lost to follow-up. The data show a steady learning curve with a time course of several years. In the current screening practice, the test pass rate is at 99.0%, the coverage is at 96% (birth rate of 2000 per annum) and almost no babies get lost to follow-up.

Prognostic value of magnetic resonance imaging findings in hearing preservation surgery for vestibular schwannoma.

OBJECTIVE: The purpose of this study was to determine whether three magnetic resonance imaging (MRI) findings (tumor size, extension to the fundus, intralabyrinthine signal intensity) have a predictive value to hearing preservation in vestibular schwannoma surgery. STUDY DESIGN: A retrospective study was conducted of preoperative high-resolution MR images in a series of consecutive hearing preservation attempts for vestibular schwannomas. PATIENTS: Twenty-six consecutive records of patients with an acoustic tumor removed via a retrosigmoid transcanal approach were analyzed, and the MR images were reviewed blindly and compared with postoperative hearing. SETTING: The study took place in a tertiary referral center. Imaging Techniques: The MR sequences used in this study were unenhanced and gadolinium-enhanced T1-weighted spin-echo images and gradient echo images (3DFT-CISS). MAIN OUTCOME MEASURES: The predictive value of three MRI signs was analyzed: tumor size, lateral extension of the tumor (with and without obliteration of the fundus), and the maintenance of, or decrease in, the intralabyrinthine signal intensity on the affected side in comparison with the signal intensity on the opposite normal side as seen on 3DFT-CISS images. RESULTS: The tumor size in ears in which hearing was preserved averaged 15 mm and was 17 mm in those cases where hearing was not preserved. Hearing was preserved in 50% of ears when the tumor did not extend to the fundus but in only 33% when the fundus was obliterated by tumor. A "normal" intralabyrinthine signal on CISS images (being an isointense signal when compared with the contralateral unaffected ear) was followed by hearing preservation in 82% of ears, whereas in cases where the intralabyrinthine signal was low, hearing was preserved in only 20%. This correlation was statistically significant (p < 0.05). CONCLUSION: The intralabyrinthine signal intensity on 3DFT-CISS gradient-echo images is a valuable additional tool for determining candidacy for hearing preservation surgery. In two cases with preoperative decrease in signal intensity of the intralabyrinthine fluids, control MRI after surgery showed spontaneous recovery of normal intralabyrinthine signal intensity. The authors hypothesize that vascular compression in the internal auditory canal by the tumor is responsible for the observed intralabyrinthine signal decrease.

Giant congenital intracranial epidermoid tumor: a case report.

A case of a large epidermoid tumor in a middle-aged woman with limited symptomatology is reported. Intracranial epidermoid tumors are slow growing and benign lesions. Although the treatment of choice consists in complete resection, partial removal may be preferred in some very extended cases presenting with minimal symptomatology because of the lower morbidity involved. This case illustrates a key-hole approach via a retrolabyrinthine route with preservation of all labyrinthine structures, including the endolymphatic sac and duct. The epidermoid was partially removed by extensive intracapsular debulking under endoscopic control with the aim of decreasing cerebral compression. All cranial nerve functions were preserved and the 6 month postoperative imaging has remained unchanged over a 2-year long follow-up period. The literature regarding this rare pathology is also reviewed.

A second gene for otosclerosis, OTSC2, maps to chromosome 7q34-36.

Otosclerosis due to abnormal bone homeostasis of the otic capsule is a frequent cause of hearing loss in adults. Usually, the hearing loss is conductive, resulting from fixation of the stapedial footplate, which prevents normal ossicular vibration in response to sound. An additional type of sensorineural hearing loss may be caused by otosclerotic damage to the cochlea. The etiology of the disease is unknown, and both environmental and genetic factors have been implicated. Autosomal dominant inheritance with reduced penetrance has been proposed, but large families are extremely rare. To elucidate the pathogenesis of the disease, identification of the responsible genes is essential. In this study, we completed linkage analysis in a Belgian family in which otosclerosis segregates as an autosomal dominant disease. After excluding linkage to a known locus on chromosome 15 (OTSC1), we found linkage on chromosome 7q, with a multipoint LOD score of 3.54. Analysis of key recombinant individuals maps this otosclerosis locus (OTSC2) to a 16-cM interval on chromosome 7q34-36 between markers D7S495 and D7S2426.