The French National Cochlear Implant Registry (EPIIC): Results, quality of life, questionnaires, academic and professional life

This study concerns the results of cochlear implantation in children and adults from French cochlear implantation centers, monitored at one, two and three years by the Cochlear Implant French Registry EPIIC. This multicenter study enrolled 2603 subjects (1667 adults and 936 children) implanted in one ear. The following parameters were studied: hearing overall performances, monosyllabic or dissyllabic word perception, speech intelligibility, self-assessment questionnaire of Cochlear Implant (CI) benefits (Abbreviated profile of Hearing aid Benefit); professional activity and schooling. This study confirms the ceiling effect in adults' performances after the 1^st year and the progressive growth in children's performances. It also shows that the contralateral hearing aid enhances performances compared to the CI alone condition, in all follow-up sessions. The French register of CIs is the only worldwide register of systematic follow-up on a period of three years and more of all adults and children implanted in a country.

MACVIA-LR (Fighting Chronic Diseases for Active and Healthy Ageing in Languedoc-Roussillon): A Success Story of the European Innovation Partnership on Active and Healthy Ageing

The Région Languedoc Roussillon is the umbrella organisation for an interconnected and integrated project on active and healthy ageing (AHA). It covers the 3 pillars of the European Innovation Partnership on Active and Healthy Ageing (EIP on AHA): (A) Prevention and health promotion, (B) Care and cure, (C) and (D) Active and independent living of elderly people. All sub-activities (poly-pharmacy, falls prevention initiative, prevention of frailty, chronic respiratory diseases, chronic diseases with multimorbidities, chronic infectious diseases, active and independent living and disability) have been included in MACVIA-LR which has a strong political commitment and involves all stakeholders (public, private, patients, policy makers) including CARSAT-LR and the Eurobiomed cluster. It is a Reference Site of the EIP on AHA. The framework of MACVIA-LR has the vision that the prevention and management of chronic diseases is essential for the promotion of AHA and for the reduction of handicap. The main objectives of MACVIA-LR are: (i) to develop innovative solutions for a network of Living labs in order to reduce avoidable hospitalisations and loss of autonomy while improving quality of life, (ii) to disseminate the innovation. The three years of MACVIA-LR activities are reported in this paper.

Comparison of echo-planar diffusion-weighted imaging and delayed postcontrast T1-weighted MR imaging for the detection of residual cholesteatoma

BACKGROUND AND PURPOSE

Echo-planar diffusion-weighted imaging (DWI) and delayed postcontrast T1-weighted MR imaging (DPI) have been proposed in previous studies to detect residual middle ear cholesteatomas, with varying results. We assessed and compared these 2 techniques in patients with canal wall-up tympanoplasty.

MATERIALS AND METHODS

This was a prospective cohort study. Patients who underwent surgery for middle ear cholesteatoma had CT scanning 9 months after the surgery. If opacity was observed (64%) on CT scans, DWI and DPI were performed before second-look surgery. CT, MR imaging, and surgical data were available for 31 patients. Charts were reviewed independently by 3 blinded examiners. Interobserver agreement for MR imaging was calculated (Cohen kappa). Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated for these techniques: 1) alone or in association, and 2) according to the residual cholesteatoma size measured during surgery.

RESULTS

Interobserver agreement was better for DWI (kappa = 0.81) than for DPI (kappa = 0.51). Sensitivity, specificity, PPV, and NPV values were 60%, 72.73%, 80%, and 50%, respectively, with DWI; and 90%, 54.55%, 78.26%, and 75%, respectively, with DPI. With cholesteatomas >5 mm, the sensitivity and specificity of DWI reached 100% and 88%, respectively, with values for DPI reaching 100% and 80%, respectively. The association of both techniques only allowed improvements in the specificity for lesions >5 mm.

CONCLUSIONS

Both techniques gave acceptable results for residual cholesteatoma detection. DWI is more specific but less sensitive than DPI. Their concurrent use may benefit patients by avoiding undue surgery.

[Usher type I syndrome in children: genotype/phenotype correlation and cochlear implant benefits]

OBJECTIVE

To assess the benefit of cochlear implant in children presenting an Usher type 1 syndrome (speech understanding, speech production intelligibility, academic performance) and to search any correlation between the phenotype and the genotype in this population.

MATERIALS AND METHODS

Retrospective case series analysis about 13 implanted Usher type I children. Cochlear implantation was performed from 1995 to 2005. Our population was divided in three groups: group 1 (implantation between 1 and 3 years of age); group 2 (implantation between 4 and 7 years of age) and group 3 (implantation between 14 and 17 years of age). Postoperative speech perception, speech production intelligibility and education settings were evaluated.

RESULTS

Molecular genetic analysis was performed in 11 patients and pathogenic mutations were identified in all cases: (mutation in myosin 7A gene in 5 cases; mutation in cadherin 23 gene in 6 cases). Four new mutations 2 in the MYO7A gene and 2 in the CDH23 gene never reported before were found. Walking delay and hearing level were not statistically correlated with the genotype abnormalities found. The speech discrimination skills, the speech production intelligibility and the academic performance were better in the group 1 children than the group 2 children after cochlear implantation. All the children of group 1 but one were in mainstreaming education. Specific language impairment was identified in two children of group 1. The group 3 children could not achieve open-set perceptive tasks after implantation--only closed-set word test can be done and their speech production remained unintelligible after cochlear implantation.

CONCLUSION

Molecular analysis of Usher type I syndrome can ascertain the diagnosis in spite of the genetic heterogeneity. In this study, clinical symptoms weren't correlated with genotypic mutations. Speech discrimination skills, speech production quality, and academic performance were correlated with the age at implant.

Influence of commercially derived lipids and a surfactant on the mode of germination and process of germ-tube formation in primary conidia of two species of Erynia subgenus Neopandora (Zygomycotina: Entomophthorales

Primary conidia of the entomopathogens Erynia (subgenus Neopandora) delphacis (1 isolate) and Erynia (Neopandora) neoaphidis (3 isolates) were stimulated to form germ-tubes with Tween 20 and with free, long-chain fatty acids, each incorporated into Entomophthora complete medium (ECM). When combined with other basal media (three tested), these compounds did not stimulate germ-tube formation. Triacylglycerols and vegetable oils, added to the same media, allowed almost complete resporulation in the fungi. In both species, Tween 20 (0.1%) encouraged greater germ-tube production (41-69%) than the fatty acids (0.1%) (< or = 36%). For E. delphacis, Tween 20 and the fatty acids differed significantly, but for E. neoaphidis the differences were almost always insignificant. Myristic and oleic acids stimulated germ-tube formation in both species. Palmitic acid allowed almost complete resporulation of the fungi, except for one isolate of E. neoaphidis that formed germ-tubes. Linoleic acid, tested only for E. delphacis, was fungistatic to most conidia. Higher concentrations of the fatty acids (< or = 1%) did not increase germ-tube formation, except 1% oleic acid which affected E. delphacis alone (>80% germination and germ-tubes). Linoleic acid, and sometimes also myristic and oleic, were fungistatic and/or toxic, depending on their concentration and on medium composition. Addition of fatty acids to ECM usually extended the lag period, and altered the morphology of the conidia and germ-tubes. These phenomena were not observed with Tween 20. Colonies were formed by E. delphacis alone, stimulated by ECM supplemented with Tween 20 or fatty acids. The results are discussed with respect to biological and physiological aspects of germination, and with respect to the mode of action of the fatty acids and the surfactant.

Normative findings of electrically evoked compound action potential measurements using the neural response telemetry of the Nucleus CI24M cochlear implant system

One hundred and forty-seven adult recipients of the Nucleus 24 cochlear implant system, from 13 different European countries, were tested using neural response telemetry to measure the electrically evoked compound action potential (ECAP), according to a standardised postoperative measurement procedure. Recordings were obtained in 96% of these subjects with this standardised procedure. The group results are presented in terms of peak amplitude and latency, slope of the amplitude growth function and ECAP threshold. The effects of aetiological factors and the duration of deafness on the ECAP were also studied. While large intersubject variability and intrasubject variability (across electrodes) were found, results fell within a consistent pattern and a normative range of peak amplitudes and latencies was established. The aetiological factors had little effect on the ECAP characteristics. However, age affected ECAP amplitude and slope of the amplitude growth function significantly; i.e., the amplitude is higher in the lowest age category (15-30 years). Principal component analysis of the ECAP thresholds shows that the thresholds across 5 electrodes can be described by two factors accounting for 92% of the total variance. The two factors represent the overall level of the threshold profiles ('shift') and their slopes across the electrode array ('tilt'). Correlation between these two factors and the same factors describing the T- and C-levels appeared to be moderate, in the range of 0.5-0.6.

[Neonatal screening of deafness: evoked otoacoustic emissions or acoustic distortion products?]

Transiently evoked otoacoustic emissions (TEOAE) allows an auditory screening in neonates above 30 dB and between 2 kHz to 4 kHz. Another type of otoacoustic emissions, the distortion product (DP) allows a similar screening and provides more specific frequency information over a broader frequency range, including frequencies below 2 kHz and above 4 kHz. The goal of this study was to determine 1) the interest of distortion product in comparison with TEOAE in a auditory screening program in neonates; 2) The predictive value of information extracted from otoacoustic emissions recordings, on frequential parameters of distortion product (DP). In this prospective study, TEOAE and DP were successively recorded in 20 neonates (34 ears) with risk of hearing impairment, using the ILO92 software and hardware. When TEOAs were no detectable (9/34), the DPs were no detectable neither (10/34). When TEOAs were detectable, the Dps carried more specific frequency information above 1 kHz in 52 to 80% of the patients. DP amplitudes have been quantitatively correlated with TEOA energy bands. Correlations between DP and TEOA have been objectivized for DP2.5 and DP4 with OE2, and for DP4 and DP6 with OE5. The correlation predictive value was above 85%. In conclusion, this study demonstrated that analysis of TEOA spectrums procures frequential information without requiring DP recordings.

Benefits of cochlear implantation in elderly patients

Cochlear implantation in elderly patients is a questionable subject. The purpose of this study was to evaluate the procedure and its outcome, the postoperative course, and the audiologic and social benefits of cochlear implantation in this population. Twenty-seven patients older than 60 years were compared with a control group of 15 adult patients. This retrospective study analyzed data concerning the outcome of the procedure, postoperative course, postoperative orthophonic test results, and answers of a questionnaire assessing the changes in communication, perception, and social outcomes. The procedure was uneventful in both groups. Minor complications were not more frequent in elderly patients. Orthophonic test results were comparable in both groups. At 12 months, 83% of the elderly patients had an open-set speech discrimination score above 60%. The benefits of cochlear implantation in terms of the quality of life are not statistically different with younger patients. Cost-utility analysis might support these findings.

[The test for the evaluation speech perception and production]

The aim of this paper is to present a Test to evaluate the speech perception and production in french profoundly hearing impaired children fitted with cochlear implant or traditional hearing aids. This test materials have been developed for children from 2 to 10 years old. This test fall into two basic categories known as speech perception and speech production. The assessment of the perceptual abilities through the use of the TEPPP is achieved across the hierarchy of perception which spans: detection, discrimination, identification, comprehension. The assessment of the speech production makes it possible to observe the speech production changes across three levels: phonetical, linguistical, intelligibility. The TEPPP, Test of Speech Perception and Production evaluation, enable us to observe if children, who receive a cochlear implant or a conventional hearing aids, obtain some degree of benefit in both speech perception and speech production.

Synchrony generation in recurrent networks with frequency-dependent synapses

Throughout the neocortex, groups of neurons have been found to fire synchronously on the time scale of several milliseconds. This near coincident firing of neurons could coordinate the multifaceted information of different features of a stimulus. The mechanisms of generating such synchrony are not clear. We simulated the activity of a population of excitatory and inhibitory neurons randomly interconnected into a recurrent network via synapses that display temporal dynamics in their transmission; surprisingly, we found a behavior of the network where action potential activity spontaneously self-organized to produce highly synchronous bursts involving virtually the entire network. These population bursts were also triggered by stimuli to the network in an all-or-none manner. We found that the particular intensities of the external stimulus to specific neurons were crucial to evoke population bursts. This topographic sensitivity therefore depends on the spectrum of basal discharge rates across the population and not on the anatomical individuality of the neurons, because this was random. These results suggest that networks in which neurons are even randomly interconnected via frequency-dependent synapses could exhibit a novel form of reflex response that is sensitive to the nature of the stimulus as well as the background spontaneous activity.

Cochlear effects of mesna application into the middle ear

Mesna (sodium 2-mercapto-ethane sulphonate) belongs to a class of thiol compounds that produce mucolysis by disrupting the disulphide bonds of the mucus polypeptide chains. The registered indications of mesna include the treatment of pathologies of the respiratory tract and, in oncology, the prevention of toxic lesions of the urinary tract by antineoplastic agents. In the E.N.T. Clinic of the University of Parma, it has been found that mesna can be used to facilitate the dissection of the various tissue layers in any surgical procedure. One of these indications is surgical treatment of cholesteatoma, which is mainly composed by keratin, a protein rich is disulphide bonds that are easily disrupted by mesna. The aim of this study was to evaluate the toxicity of mesna application into the middle ear on the cochlear anatomy and physiology. Three groups of guinea pigs were used as subjects. Mesna solution (10 or 20%) was applied in one ear, while the opposite ear received a placebo (saline solution). Toxicity of mesna was assessed by means of transmission electron microscopy (TEM), scanning electron microscopy (SEM), and auditory brain-stem response (ABR). TEM and SEM did not show any toxic effect on cochlear morphology. There were no differences in ABR thresholds and wave III amplitude and latency between mesna-treated and control ears.

[Chemical labyrinthectomy: results and applications]

GOAL OF THE STUDY

Unilateral Menière's disease can be treated by chemical labyrinthectomy. The goal of this work was to report our clinical experience with chemical labyrinthectomy, and to discuss the respective value of labyrinthectomy and of vestibular neurotomy for treating unilateral Menière's disease.

METHODS

Twelve patients underwent chemical labyrinthectomy using middle ear gentamicin infusion. Before treatment, patients had a pure tone audiogram and a vestibular caloric testing. After treatment, patients had a clinical assessment at 1 and 6 months after treatment (pure-tone audiogram, vestibular caloric testing), and answered a questionnaire at 1 and 2 years following the treatment (number of vertigo attacks, ataxia, tinnitus, subjective assessment of the method by the patient).

RESULTS

At two years post-treatment, the vertigo cure rate was 91.6% (ABC using AAOO criteria), vestibular function was abolished in 70% of cases, ataxia was reported in 42% of patients, 16.6% of patients had hearing deterioration above 20 dB HL (C following AAOO criteria), tinnitus was decreased in 50% of cases. Of 12 patients, 8 were satisfied.

CONCLUSION

Chemical labyrinthectomy cures vertigo in Menière's disease, with similar cure rate than vestibular neurotomy. Minor complications can occur with chemical labyrinthectomy. This method should be used in more patients.

Information processing with frequency-dependent synaptic connections

The efficacy of synaptic transmission between two neurons changes as a function of the history of previous activations of the synaptic connection. This history dependence can be characterized by examining the dependence of transmission on the frequency of stimulation. In this framework synaptic plasticity can also be examined in terms of changes in the frequency dependence of transmission and not merely in terms of synaptic strength which constitutes only a linear scaling mechanism. Recent work shows that the frequency dependence of transmission determines the content of information transmitted between neurons and that synaptic modifications can change the content of information transmitted. Multipatch-clamp recordings revealed that the frequency dependence of transmission is potentially unique for each synaptic connection made by a single axon and that the class of pre-postsynaptic neuron determines the class of frequency dependence (activity independent), while the unique activity relationship between any two neurons could determine the precise values of the parameters within a specific class (activity dependent). The content of information transmitted between neurons is also formalized to provide synaptic transfer functions which can be used to determine the role of the synaptic connection within a network of neurons. It is proposed that deriving synaptic transfer functions is crucial in order to understand the link between synaptic transmission and information processing within networks of neurons and to understand the link between synaptic plasticity and learning and memory.

Influence of communication mode on speech intelligibility and syntactic structure of sentences in profoundly hearing impaired French children implanted between 5 and 9 years of age

OBJECTIVE

The purpose of this study was to examine the speech production in French profoundly hearing impaired children, focusing on word intelligibility, sentences syntax, and sentence pattern stages, by incorporating direct comparisons between speech production skills and communication modes in the same children.

DESIGN

The design of the study incorporated a within-subject, repeated measures design for assessing speech production intelligibility and syntax.

SETTING

Montpellier Pediatric Cochlear Implant Center.

SUBJECTS

Twelve prelingually deafened French children who received a Nucleus multichannel cochlear implant (mean age at the time of implantation was 7 years 2 months) served as subjects for the speech production assessment.

MAIN OUTCOME MEASURES

Speech production intelligibility, syntax, and sentence pattern stages were assessed at 1, 2 and 3 years postimplant. Speech production skills were related to the communication mode of the children (auditory-oral, four children; cued-speech, four children; sign-language, four children).

RESULTS

Scores on word intelligibility steadily improved with increased experience with the implant, ranging from 18% before implantation to 54.5% at 36 months postimplantation in the overall population. The highest scores were found in the cued-speech group with an averaged score of 66.8% at 36 months postimplant. The number of syntactic elements increased over time with implant experience. Children receiving cued-speech education had higher scores by 3 years postimplantation than children receiving either auditory-oral or sign-language modes of communication. Language level (sentence pattern stages) also improved with increased experience with the device. By 3 years postimplantation, children receiving auditory-oral or cued-speech instruction were able to produce sentences; however, the sign-language children failed to do so at a rate comparable to the other children. Language level was significantly higher in the oralist or cued-speech educated children than in the sign-language group.

CONCLUSIONS

Speech production skills improved with increased experience using a cochlear implant. Word intelligibility, syntactic structure of sentences, sentence pattern stages improved gradually over time. Production skills were greater in the cued-speech educated children group than in the auditory oral or sign-language groups. Statistically better sentence pattern stages were found in the auditory oral and sign-language groups.

Adenovirus-mediated in vivo gene transfer in guinea pig middle ear mucosa

This article describes a study designed to assess the feasibility of using recombinant adenovirus for delivering therapeutic peptides in vivo in the guinea pig middle ear cleft. A recombinant adenoviral vector AdCMVsp1 LacZ containing the Escherichia coli beta-galactosidase was injected into the middle ear space. Qualitative assessment of cell middle ear transfection was performed on day 2 by light microscopy study, after injecting a multiplicity of infection (MOI) ranging from 0 to 1000. At an MOI of 30, 30% of the promontory area epithelial cells were stained. An MOI of 50 stained 60% of the cells and an MOI of 100 or more stained more than 90% of the cells. The duration of cell transfection was studied after injecting an MOI of 50. The percentage of stained cells was 60% on day 2, 10% on day 7, and 0% on day 14. Middle ear mucosal inflammation, consisting of a granulocytic infiltrate, was observed when an MOI above 50 was used. Even at a high MOI (500), no staining could be found in the cochlea, in the facial nerve, in the brain, or in visceral organs. These data suggest that recombinant adenovirus vectors can be used to transfer genes in the middle ear. This method appears to be safe, and may be envisaged as a short-duration treatment to transfer genes in vivo in the treatment of middle ear diseases.

Selection criteria for cochlear implants in children

OBJECTIVE

To determine the selection criteria for cochlear implantation in children.

SETTING

Hospital pediatric implant center.

PATIENTS AND INTERVENTIONS

Selection of patients depends on medical evaluation, audiometric data, speech discrimination, communication skills, cognitive skills, and psychosocial factors. Patient selection is based on tonal audiometry, computed tomography, magnetic resonance imaging, and electrophysiologic tests. Side of implantation is chosen according to cochlear structure, duration of deafness, and dominant handedness.

RESULTS

Ninety-eight cochlear implantations with the Nucleus multichannel implant have been performed at this center since 1990.

CONCLUSION

The selection of children for cochlear implantation require close collaboration between the pediatric surgical team, the educational team, and the family.

Monitoring eustachian tube opening: preliminary results in normal subjects

Sonometry studies the changes of sound intensities induced by the eustachian tube opening in the external meatus when a constant sound is applied in the nasal cavity. The function of the eustachian tube is not disturbed by the test procedure. An original portable device with a high signal-to-noise ratio has been developed in our lab. This device was able to detect a 6-dB sound pressure level (SPL) signal in a 100-dB SPL noise. Long-duration recordings of auditory tubal openings could be performed. This work presents the data found in normal subjects. One hundred twenty healthy ears were recorded. Eustachian tube openings were detected in 62.5% of the cases. Of the 1777 openings recorded, the average opening duration was 430 ms +/- 183 ms. The average number of eustachian tube openings was 21.7+/-16.4 (for 15 minutes). All swallowing did not necessary open the eustachian tube. This work shows that this new device allows long-duration recording of eustachian tube function in everyday life conditions.

Speech perception skills and speech production intelligibility in French children with prelingual deafness and cochlear implants

OBJECTIVE

To examine speech perception and production intelligibility in French children with prelingual deafness who received multichannel cochlear implants.

DESIGN

Within-subject, repeated-measures design for assessing speech perception and a cross-sectional design for assessing overall speech intelligibility.

SETTING

A pediatric cochlear implant center.

SUBJECTS

Sixty-four French children with prelingual deafness who received multichannel cochlear implants (mean age at time of implantation, 3 years 11 months) underwent assessment for speech perception. A subset of 16 children who received implants by 3 years of age underwent assessment for speech intelligibility.

MAIN OUTCOME MEASURES

Speech perception skills were assessed using phoneme detection, closed-set word and sentence recognition, and modified open-set (MOS) recognition. Speech intelligibility was assessed by asking 50 listeners to identify recorded speech samples from the subjects. Dependent variables for the studies consisted of percent of correct items.

RESULTS

After implantation, all children were able to detect phonemes by 3 months. Closed-set word and sentence identification reached 100% accuracy by 48 months (7 children with 4 years of implantation experience). Some children (8 of 48) demonstrated some MOS recognition after 1 year. Modified open-set recognition averaged 67.9% by 42 months (12 children available) and 80% by 48 months (7 children available). Overall speech intelligibility was 4.2% after 1 year, 30.7% after 2 years, 55.2% after 3 years, and 74.2% after 4 years. Within-subject comparison of MOS recognition and overall speech intelligibility scores revealed an insignificant trend for high perceptual performance to be associated with higher speech intelligibility scores (P = .17). There also was a tendency for higher performance to be associated with longer implantation experience.

CONCLUSIONS

Speech perception scores appear to increase with increased experience using a cochlear implant. Overall speech intelligibility appears to steadily improve with increased experience and appears to be poorly related to perceptual performance on MOS recognition tasks.

Electrical stimulation activates two different sites within the guinea pig cochlea

This study investigates whether auditory brainstem responses (ABRs) can be used to assess the functioning of electrically stimulated cochleas. Electrically evoked auditory brainstem responses (EABRs) were recorded in guinea pigs with normal hearing and guinea pigs deafened by amikacin, a powerful ototoxic antibiotic, combined with diuretic aminooxyacetic acid (AOAA). Two different types of EABRs were observed in normal animals, depending on the electrical pulse intensity applied to the round window: long-latency brainstem responses were evoked by low stimulation intensities, short-latency brainstem responses by high intensities. The absence of effect of strychnine applied intracochlearly ruled out the possibility of medial efferents being involved in these responses. Conversely, an intracochlear application of tetrodotoxin (TTX), an Na(+)-channel blocker, resulted in the disappearance of both types of responses, attesting that the sites activated by the electrical stimulation were located within the cochlea. In AOAA/ amikacin poisoned cochleas, in which most of the hair cells were missing with apparently normal ganglion neurons, the long-latency brainstem responses evoked by low intensities were completely lacking. These findings suggest that low currents applied to the round window of the guinea pig cochlea primarily activate the hair cells, the neurons being directly excited at higher intensities.

[Aberrant intra-petrous internal carotid artery: apropos of a case]

This article illustrates a case of an aberrant pathway of the petrous portion of an internal carotid artery presenting as a cholesteatoma. This is a case of a 53 y.o man presenting with unilateral otalgia and vertigo. Otoscopic examination revealed a whitish retro-tympanic mass accompanied by a conduction hearing loss mimicking a cholesteatoma. An exploratory tympanotomy was performed. The surgical procedure was interrupted after needle aspiration of the mass suggesting an aberrant course of the petrous portion of the internal carotid artery. Authors report a review of the literature with an emphasis on the differential diagnosis, clinical and paraclinical diagnostic work-up. A thorough knowledge of this anomaly is required to avoid an iatrogenic risk during any otological surgery.

Criteria for selecting the side for cochlear implantation

Choice of the side for cochlear implantation should take into account peripheral (extracortical) factors and central (cerebral dominance) factors. From 111 patients implanted with a Nucleus device, the authors found that significant peripheral factors were the degree of cochlear ossification, the duration of deafness before cochlear implantation, and the preoperative promontory test dynamic range (degree of response on the promontory test in decibels); cause of deafness and residual hearing were not correlated with speech discrimination. Cerebral dominance was indirectly determined by handedness. Handedness laterality was determined by a questionnaire. There was no significant difference in results between patients implanted on their dominant side and patients implanted on their nondominant side. When ears are different according to their peripheral factors, the authors suggest implanting the better ear, provided there is no significant hearing in that ear. When both ears are identical, the side of implantation should be the side of handedness laterality to facilitate device manipulation (a practical reason).

Intraoperative facial nerve monitoring in posterior fossa acoustic neuroma surgery

Intraoperative facial nerve monitoring has become an indispensable tool during cerebellopontine angle surgery. Ninety-seven patients underwent surgical removal of an acoustic neurinoma with the use of a pneumatic sensor monitoring between January 1, 1986, and December 31, 1990. In the early postoperative period, a normal or near-normal facial function (grades I and II) was achieved in 86% of the patients, a moderate dysfunction (grade III) was present in 7%, and a total or severe dysfunction (grades V or VI) was present in 6%. Normal function at 1 year was achieved in 90.5% of the patients, 4% were grade II, a moderate dysfunction (grade III) was present in 2%, and 3% showed a total or severe dysfunction (grade V and VI). The incidence of normal function decreased with tumor size, with an occurrence rate of 100%, 94%, and 91% in small, medium, and large tumors, respectively. In eight consecutive patients, all responses detected by the monitoring during the operation were collected and analyzed according to intraoperative events. Analysis of the results indicate that 95% of the 316 mechanically induced stimulations were of small or extremely small amplitude, and only 5% were of moderate amplitude. A medial-to-lateral strategy of dissection, preservation of the arachnoid veil over the facial nerve, a control by the monitoring of the amount of traction, and a more widespread use of sharp dissection were the major approaches to reduce surgical trauma during dissection.

Incorporation of D-[3H]-glucosamine and L-[3H]-fucose into the developing rat cochlea

The uptake of two tritiated carbohydrates, D-[3H]-glucosamine and L-[3H]-fucose, to the developing rat cochlea was examined using light and electron microscopic radioautography. Both carbohydrates, administered to in vitro developing rat cochleas, shared a similar ultrastructural labeling pattern on the microvilli and apical cell region and on the tectorial membrane (TM) fibrils. On embryonic day 18, the radiolabeling appeared on the apical surface of the undifferentiated epithelium that will develop into both spiral limbus and Kölliker's organ (KO), while on postnatal day (PD) 1, it was only located on the apical surface of the KO. When D-[3H]-glucosamine was administered in vivo to newborn rats, the radiolabeling was observed in the TM covering the KO at PD 3. Lastly, D-[3H]-glucosamine administered in vivo to PD 7 rats, appeared at PD 9 in the TM region lying just above the organ of Corti. The present findings support the previously suggested leading role of the spiral limbus and KO in the secretion of the TM during cochlear development. The secretion of carbohydrates, and probably of other matrix components, starts on the spiral limbus and KO region and progressively extends to the organ of Corti.

Fibroblast growth factor improves the healing of experimental tympanic membrane perforations

Topical application of FGF (fibroblast growth factor), a potent mitogen for mesodermal and neuroectodermal cells, was given to promote the healing of tympanic membrane perforations in rats. Calibrated tympanic membrane perforations were performed in 30 rats. At day 0, each rat received 40 microliters of placebo in the right ear and 40 microliters of a solution containing FGF in the left ear at different concentrations. The quality of healing was observed by otomiscroscopy and by light microscopic examination of histological sections. The mean time of closure was significantly shorter in ears receiving an amount of 400 ng FGF (6.1 days), as compared to non-treated ears (8.8 days). Using a higher dose of FGF, the promoting effect was counterbalanced by a high rate of myringitis. Using a dose of 200 ng of FGF, no difference was noticed between placebo group and FGF group.

Evoked otoacoustic emissions from normal newborns and babies admitted to an intensive care baby unit

Click-evoked otoacoustic emissions (OAEs) were recorded from both ears in two groups of neonates ranging in age from a few days to two months after birth. The first group consisted of 55 full-term neonates with normal developmental history and health status, including absence of middle ear disease and familial history of hearing loss. The second group consisted of 40 infants admitted to an intensive care baby unit for various pathological conditions (anoxia, prematurity, hyperbilirubinemia, meningitis). The method achieved 97% success in assessing cochlear function in the normal group; it was possible to identify a clear and reproducible response in all ears, except 3, at 70 dB SPL (i.e. approximately 30 dB nHL). The detection-threshold of OAEs was comparable to that measured in adult ears. Several babies from the second group produced no OAEs and were also tested by auditory brainstem responses (ABR): these infants demonstrated ABR thresholds higher than 30 dB nHL. OAEs provide an objective tool for a rapid and effective screening test for cochlear impairment in neonates.

[Cochlear implants in 1990]

The various techniques of cochlear implantation are described. Implants may be divided into mono- and multi-electrode and into intra- and extra-cochlear. Cochlear implants are indicated only in patients with total or deep bilateral deafness with residual fibres still functioning in the acoustic nerves. Intra-cochlear multi-electrode implants are the most sophisticated ones and usually provide better performances than those observed with mono-electrode implants.

Short latency vestibular potentials evoked by electrical round window stimulation in the guinea pig

Short-latency potentials evoked by round window electrical stimulation were recorded in guinea pig by means of vertex-pinna skin electrodes using averaging techniques. Constant current shocks of 20 microseconds or 50 microseconds (25-300 microA) were used to evoke both auditory and vestibular brain-stem potentials. Pure auditory potentials, comparable to those evoked by acoustic clicks, were obtained by 20 microseconds electrical stimuli and disappeared during an auditory masking procedure made with a continuous white noise (110 dB SPL). Short latency potentials labeled V1, V2 and V3 were obtained by 50 microseconds electrical stimuli during an auditory masking procedure. This response disappeared after specific vestibular neurectomy, whereas the auditory response evoked by acoustic clicks or by electrical stimulation remained unchanged, suggesting that these latter potentials had a vestibular origin.

The properties of spontaneous and evoked acoustic emissions in neonates and children: a preliminary report

Evoked acoustic emissions (EAEs) and spontaneous acoustic emissions (SAEs) recordings hold some promise as a fast, objective and non-invasive audiological procedure, especially in children. However, accurate interpretation in the emission response must be based on the basic properties of the emissions present in a younger age group. In so doing, the properties of emissions were investigated in 49 ears from 26 children, whose ages varied between 2 days and 10 years. EAEs could be recorded in all normal ears, but the incidence of long-duration EAEs decreased with age. There were no statistically significant variations in recording the EAEs detection threshold with age. The incidence of SAEs also decreased with age.

Clinical applications of evoked acoustic emissions: results in normally hearing and hearing-impaired subjects

Click-evoked otoacoustic emissions were recorded in a group of normally hearing subjects (n = 52 ears) and a group of patients demonstrating several common types of sensorineural hearing loss (n = 85 ears) in order to study the clinical applicability of acoustic emissions. In the normally hearing population, all ears demonstrated acoustic emissions that could be elicited at intensities below the normal subjective threshold for the sequence of clicks (mean, -5.2 dB hearing level [HL]). Sixty-seven percent of the normal ears showed long (greater than 20 ms) click-evoked emissions, and spectral analysis showed a broadband spectral component with several narrowband frequency peaks. In patients with sensorineural hearing loss, the incidence of acoustic emissions decreased and the detection threshold increased linearly with increasing threshold. No emissions were elicited from ears exhibiting subjective click thresholds greater than 35 dB HL. Hearing-impaired ears showed a significantly higher proportion of short duration emissions and a significant reduction in the mean number of narrowband frequency peaks in comparison to the controls. Therefore, acoustic emissions can be used as a reliable technique for objective study of normal micromechanical activity within the cochlea and for detection of subtle changes in cochlear disease. However, they have not been demonstrated to be useful in differentiating cochlear disease.

Evoked otoacoustic emissions in patients with acoustic neuromas

Click-evoked otoacoustic emissions were recorded in 28 patients with surgically proven acoustic neuromas and 22 patients with brain stem pathologic disorders. Data collected in acoustic tumor ears were compared with those obtained in 30 nontumor ears demonstrating sensorineural hearing losses. Acoustic emissions were altered (increased detection-threshold or no detectable emissions) in all ears with eighth nerve tumors and were not affected in those with brain stem pathologic conditions that do not involve cochlear function. The properties of acoustic emissions were similar in both tumor and nontumor ears with hearing loss, which suggests that acoustic tumors usually produce a cochlear hearing loss.

Screening for auditory dysfunction in infants by evoked oto-acoustic emissions

Auditory threshold using auditory brain-stem responses (ABR) was determined in 30 ears from normally-hearing infants and 16 ears from infants with sensorineural deafness. In the same population, evoked oto-acoustic emissions (EOAEs) in response to a click of 20-dB hearing level were recorded. The presence of EOAEs was correlated with ABR thresholds. Evoked oto-acoustic emissions were always present when ABR wave V threshold was equal to or below 30-dB hearing level. On the contrary, infants with ABR thresholds higher than 40-dB hearing level never had EOAEs. As the recordings of EOAEs could be obtained more rapidly than ABR thresholds (average duration: five minutes vs 40 minutes), EOAEs could hold some promise as an objective, easy, and noninvasive test for screening auditory dysfunction in infants.

Evoked oto-acoustic emissions from adults and infants: clinical applications

Evoked oto-acoustic emissions (EOAEs), i.e. sounds emitted by the cochlea in response to a click, are recordable in the ear canal by a miniature microphone. They reflect an active cochlear biomechanism based upon OHC function, which accounts for the exquisite properties of sensitivity and frequency selectivity of the cochlea. EOAE recordings can therefore be considered an objective, easy, rapid and non-invasive audiological procedure which can be used to investigate the most sensitive part of the cochlea. From our experience of more than 300 recordings, we propose several clinical applications of EOAEs: 1) objective assessment of sensorineural hearing loss; 2) staging Meniere's disease by recording glycerol-induced changes; 3) diagnosis of retrocochlear pathology, and 4) screening of auditory function in infants.

A correlative study of evoked otoacoustic emission properties and audiometric thresholds

Correlations were made between the detection thresholds of evoked otoacoustic emissions (EOAEs), subjective click thresholds, and mean audiometric thresholds in 240 normal and hearing-impaired ears. EOAEs have never been observed when subjective click thresholds or mean audiometric thresholds were equal to or greater than 35 dB HL. EOAEs were always found when click thresholds were equal to or lower than 15 dB HL and when mean audiometric thresholds were equal to or lower than 22 dB HL. The incidence of EOAEs decreased and EOAE thresholds increased with increasing click or mean audiometric thresholds.

Evoked otoacoustic emissions: a fundamental and clinical survey

Evoked otoacoustic emissions (EOAEs) hold some promise as a fast, objective and noninvasive procedure to study the cochlea at the outer hair cell level. This paper summarizes the fundamental aspects of EOAEs, in particular their relationship with the active biomechanical properties of the cochlea. The properties of EOAEs are analyzed in normally hearing ears, in ears with sensorineural hearing loss, especially in Ménière's disease, in acoustic neuromas and in central deafness; the properties of EOAEs were also evaluated as to their suitability for screening auditory dysfunction in infants.

Evoked otoacoustic emissions: normative data and presbycusis

Evoked acoustic emission (EAEs) recordings hold some promise as a fast, objective and non-invasive audiological procedure to study the cochlea at the outer hair cell (OHC) level. However, accurate interpretation in the EAE response must be based on a knowledge of its variations with age. In order to investigate age-related changes of EAEs, the properties of EAEs (incidence, threshold and spectrum) were studied in 151 ears from subjects whose age varied between 2 and 88 years. EAEs were present in 100% of the tested subjects until the age of 60 years. After this age, EAE incidence fell to 35%. EAE threshold did not vary until the age of 40 years but increased linearly after this age. Thus, complementary information on OHC degenerative changes in presbycusis could be deduced from these data.