Chantal Ferber-Viart

Fully implantable hearing device as a new treatment of conductive hearing loss in Franceschetti syndrome.

The objective is to investigate a new therapeutic option for treatment of conductive hearing loss in children with Franceschetti syndrome. A Carina fully implantable device with the MET V transducer for conductive applications was implanted in a 14-year-old male suffering from bilateral conductive hearing loss (mean PTA loss: 70 dB on the right ear and 64 dB on the left ear) secondary to Franceschetti (a.k.a Treacher Collins) syndrome with bilateral agenesis of external ear canal and ossicular malformation. Postoperative unaided PTA was unchanged by the surgical procedure. When the implant was activated, mean PTA was 29 dB improved on the implanted ear. The capacity of the Carina MET ossicular stimulator to provide appropriate gain relative to the degree of hearing loss indicates that the device may be a viable treatment for children with agenesis of external auditory canal and severe malformation of the middle ear. However, these initial results need to be furthered by: (1) additional studies including a greater number of patients to confirm these preliminary results and (2) a long-term follow-up must be carried out to detect possible long-term cochlear adverse effects, in particular on the basilar membrane.

Characteristics of 629 vestibular schwannomas according to preoperative caloric responses.

Objectives: To assess the contribution of preoperative caloric responses in patients with vestibular schwannoma on the following: preoperative parameters and postoperative results (facial function and hearing preservation). Study Design: Retrospective review of prospectively collected data. Setting: Tertiary referral center. Patients: A group of 629 patients who underwent vestibular schwannoma surgery. Main Outcome Measures: Caloric responses are quantified in terms of slow-phase nystagmus velocities generated during warm and cool irrigations of each ear, with asymmetry between the two horizontal semicircular canals was quantified by the Jongkees formula. When unilateral weakness (UW) was less than 20%, caloric response was regarded as normal (group N). When UW was greater than 70%, caloric response was classified as severe caloric weakness (group S), and when the UW was comprised between 70 and 20%, caloric response was classified as moderate (group M) caloric weakness (CW). Results: 47.8% of the studied patients were included in group S, 38.2% in group M, and 14% in group N. Preoperative mean hearing loss was higher in group S compared with that in groups M and N. The auditory brainstem response threshold was higher in group S compared with that in group N and also higher in group M compared with that in group N. A good correlation was observed between CW and tumor size. Postoperative facial palsy was more frequent in group S compared with groups N and M. Postoperative hearing preservation was more frequently observed in group N compared with groups S and M. Conclusion: Our results suggest that caloric responses are well correlated with the studied preoperative and intraoperative factors and provide predictive factors with regard to postoperative facial palsy and hearing outcome.

Auditory screening in high-risk pre-term and full-term neonates using transient evoked otoacoustic emissions and brainstem auditory evoked potentials

The present report concerns a 3 year, 8 month hearing screening in 1531 high-risk neonates by means of two successive transient evoked otoacoustic emission (TEOAE) recordings followed, in cases of suspected hearing loss, by brainstem auditory evoked potential (BAEP) recording and otolaryngology (ORL) consultation. After TEOAE 1 and 2 and BAEP testing, 1361 infants (88.9%) were declared normal, and 170 (11.1%) suspected of hearing loss. Of these 170, 58 showed bilateral and 26 unilateral impairment. Definite hearing loss on ORL consultation was diagnosed in 14 infants (0.9% of the screened population as a whole); 22 are still being followed, while 86 (5.6%) failed to consult for diagnosis. The mean age on diagnosis of definite hearing loss was 9.9 +/- 4.9 (range 4-20) months. Several auditory function risk factors proved more frequent in deaf than in normal children. Our results show that early hearing loss screening in at-risk neonates needs to be pursued.

Perioperative complications after translabyrinthine removal of large or giant vestibular schwannoma: Outcomes for 123 patients

Abstract Conclusion: Large vestibular schwannomas are benign but dangerous tumors. The translabyrinthine approach allows the surgeon to limit vital and functional complications due to the disease itself or to its surgical removal. Objective: Morbi-mortality study focused on large vestibular schwannoma surgically treated by translabyrinthine removal. Methods: This was a retrospective review of prospectively collected data in a series of 123 patients who underwent translabyrinthine removal of a large vestibular schwannoma (>4 cm in the cerebellopontine angle, stage IV). All surgical and medical complications and facial function were reviewed, with a 1-year follow-up. Results: Mortality during the first year was 0.8% (one case of infarct of the anterior inferior cerebellar artery, fatal after 8 months). In all, 4.9% of patients underwent a second surgery (for delayed hemorrhage or cerebrospinal fluid leak) during the first months after removal of a large vestibular schwannoma; 3.2% of patients experienced definitive neurologic complications (one death, one cerebellar disturbance, and two cases of 10th cranial nerve palsy).

Cochleovestibular Afferent Pathways of Trapezius Muscle Responses to Clicks in Human

Brief intense clicks cause short-latency cervical muscles microcontractions which are supposed to be of vestibular origin. Averaging these microcontractions allows myogenic vestibular evoked potentials (MVEP) to be obtained. MVEP from the trapezius muscles were investigated in normal subjects, cochleovestibular nerve-damaged patients and patients with a vestibular or a cochlear lesion. Muscular responses were recorded on right and left trapezius by averaging from surface electrodes following right and left monaural 100 dB hearing level click stimulation. In normal subjects, responses to monaural stimuli were bilateral, of equal amplitude and latency in left and right trapezia. Normal response consisted of four consecutive waves, labelled p13, n23, p32 and n40 according to their polarity (p, positive; n, negative) and mean peak latency in msec. In total unilateral cochleovestibular damaged patients, auditory stimulation of the affected side gave no MVEP either ipsilateral or contralateral to the stimulation. In the case of selective cochlear lesion, stimulation of the affected side gave MVEP which was present on ipsilateral and contralateral trapezius muscles. The four successive waves were present with a normal latency; however, amplitude was lower than that obtained after stimulation of the healthy ear. In the case of selective vestibular lesion, the four waves of MVEP were again present with normal latency but with reduced amplitude. Responses were present on both the ipsilateral and contralateral trapezius muscle. It is concluded that normal MVEP recorded on the trapezius muscles are bilateral and consist of four waves, the amplitude of which could depend on the simultaneous stimulation of both cochlear and vestibular afferents. In the case of unilateral cochlear and/or vestibular impairments responses were present on both ipsilateral and contralateral trapezius muscles. Latencies had normal values but amplitudes were reduced. MEVP recorded on trapezius muscles were absent in the case of total cochleovestibular damage.

Otoacoustic emissions and brainstem auditory evoked potentials in children with neurological afflictions

Findings are reported for evoked otoacoustic emissions (EOAEs) recorded from 22 children with neurological afflictions, whose brainstem auditory evoked potentials (BAEPs) were pathological on at least one side (41 ears explored). Our results confirmed that EOAEs are always present in children and infants having normal BAEPs. Absence of EOAE (n = 22) was almost always related to middle ear or cochlear damage with BAEPs indicating diagnoses, respectively, of transmission damage (n = 7) or endocochlear damage (n = 16). Conversely, for BAEP diagnoses of retrocochlear damage (n = 12), EOAEs were always present. EOAEs associated with BAEPs, therefore, appear to offer a well-adapted technique for precise etiological diagnosis of childhood hearing loss. When no wave is identifiable by BAEP recording, EOAE presence indicates retrocochlear damage.

Bone-anchored hearing aid in unilateral inner ear deafness: electrophysiological results in patients following vestibular schwannoma removal

Conclusions. The results show that the healthy cochlea perceives one auditory stimulus from two auditory signals: the first through normal air conduction and the second provided by the bone-anchored hearing aid (BAHA). This artificial acoustic difference could partly explain ‘pseudo’ binaural hearing. Functional cerebral imaging using the same experimental procedure is now necessary. Objectives. The aim of this study was to evaluate electrophysiological phenomena induced by BAHA on brainstem and long-latency auditory evoked potentials (AEPs) to understand how patients recover a ‘pseudo’ binaural sensation with only one functional cochlea. Patients and methods. This prospective study included 10 patients operated via the translabyrinthine approach and who received implants on the deaf side. Electrophysiological recordings were performed at least 2 months after BAHA use. Brainstem and long-latency (N1, P2, N2, P300) AEPs were studied in free field according to four conditions: 1, without BAHA; 2, with BAHA; 3, with BAHA and normal ear occluded; 4, without BAHA and normal ear occluded. Results. For brainstem AEPs, we found significantly longer latencies of waves III and V in condition 3 compared with condition 1. For long-latency AEPs, comparison between conditions showed no significant differences.

Are stage IV vestibular schwannomas preoperatively different from other stages

Objective: The aim of this study was to focus on the clinical and paraclinical symptoms of patients suffering from Stage IV vestibular schwannomas (VSs). Patients: In this prospective study, we included 734 patients who have VS and candidates for operation. Main Outcome Measures: Patients were classified as having Stage I, II, III, or IV tumors according to Tos criteria as evaluated by magnetic resonance imaging. Preoperative Clinical Evaluation: We recorded the occurrence of complaints (%) and duration (yr) of hearing loss, tinnitus, and balance disorder. Preoperative paraclinical evaluation included pure-tone (PTA) and speech audiometry, auditory brainstem response (ABR) patterns, and vestibular deficit at videonystamography (VNG). Continuous variables were compared between Stage IV and other stages using analysis of variance. Qualitative variables expressed as a percentage of presence were compared between Stage IV and other stages using percentage comparison. Results: Quantitative Parameters. Patients with Stage IV VS were significantly younger as compared with patients with other stages. Stage IV hearing loss was greater compared with other stages at 250 and 500 Hz but smaller at 2,000 and 8,000 Hz. We found no difference in the loss of PTA between Stage IV and the other stages. Speech discriminancy score was smaller in Stage IV. The durations of hearing loss, tinnitus, and balance disorders were similar whatever the tumor stage. Auditory brainstem response patterns showed no difference in Wave III latency between Stage IV VS and other stages, whereas Wave V latency and V-I interval were higher in Stage IV. Both ABR threshold and VNG caloric deficit were higher in Stage IV VS compared with other stages. Qualitative Parameters. The percentage of patients with Stage IV was lower than that with Stages II and III. The percentage of men and women was similar in all stages. The occurrence of hearing loss was similar in all stages, whereas that of tinnitus was lower in Stage IV compared with Stages I and II. In contrast, the occurrence of balance disorder was higher in Stage IV compared with all other stages. Conclusion: In clinical and paraclinical manifestation, Stage IV VS is different from the other stages. The PTA differences may be attributed to the younger age. Occurrence of clinical symptoms, ABR, and VNG pattern can be explained by the fact that Stage IV develops rapidly in the vestibular, rather than the cochlear nerve and by the fact that larger tumors can be cerebellar compression. This has been confirmed by the higher occurrence of balance disorders in Stage IV and the lower occurrence of tinnitus with similar hearing loss in all stages.

Type of initial brainstem auditory evoked potentials (BAEP) impairment and risk factors in premature infants

Brainstem auditory evoked potentials (BAEPs) were recorded in 89 premature infants aged between 34 and 52 weeks. 47.2% had normal and 52.8% abnormal BAEPs in at least one ear. Seven risk factors were taken into account: birth weight lower than 1500 g, hypoxia, neurological damage, fetal pathology, associated malformation, the use of ototoxic drugs, and exchange transfusion. The type of BAEP impairment was defined as either endocochlear, transmission or retrocochlear damage. Percentage BAEP impairment was higher in case of hypoxia (63.3%) but remained similar whether the other risk factors were present or absent. Transmission impairment was more frequent in case of birth weight lower than 1500 g, hypoxia or ototoxic drug administration; Endocochlear damage occurred more frequently when ototoxic drugs had been used or exchange transfusion performed. When birth weight was lower than 1500 g, transmission damage was more frequent than when birth weight was higher than 1500 g. In contrast, endocochlear damage was more frequent when birth weight was higher than compared with lower than 1500 g. In male infants, BAEP impairment was more frequent and more often of retrocochlear type than in female infants. BAEP impairment was more frequently of endocochlear type in female compared to male infants. Among the 89 premature infants recorded, 11.2% has endocochlear damage corresponding to potentially handicapping hearing loss. These results are discussed with reference to the literature.

Stacked tone-burst-evoked auditory brainstem response (ABR): preliminary findings.

In 1997, Don and his co-workers described a new method for evaluating the auditory brainstem response (ABR)—yielding the stacked-wave-V ABR—which may permit the reliable detection of even small vestibular schwannomas (VSs). However, this method requires a masking technique that may not be readily available to the clinician. Furthermore, relatively high-level noise is required and may be annoying to the patient. An alternative method that might permit the same manipulation of the ABR was thus explored whereby tone-bursts (TBs) were used to obtain frequency-specific ABRs. The goal of the study was to determine whether TBs could be used to achieve the sort of de-convolution and subsequent enhancement of wave V reported with the original method of Don et al. First, the TB-stacked ABR (wave V) was compared to that obtained using derived narrowband masked ABRs in young normal-hearing subjects. Second, the TB method was employed in subjects with unilateral VSs and in patients with unilateral sensory hearing loss in a preliminary clinical trial. The observed results are promising for the use of the TB method as an alternative approach to ABR ‘stacking’ and warrant further research and development of the TB method. En 1997 Don y colaboradores describieron un nuevo método para evaluar las respuestas auditivas del tallo cerebral. (ABR)-con énfasis en la acumulación de la onda V-que puede permitir una identificación con liable incluso de pequeños schwannomas vestibulares (VSs). Sin embargo, el método requiere una técnica de enmascaramiento que puede no estar disponible para los clinicos. Mas aún, se requiere un ruido de nivel relativa-mente elevado que puede ser molesto para el paciente. Un método alternativo que permite la misma manipulación de las ABR se exploró usando bursts tonales (TBs) para obtener ABRs de frccuencia específica. El objetivo de este estudio fue determinar si pueden ser usados los TBs para obtener un mejor despliegue y el subsecuente realce de la onda V reportado con el método original de Don y cols. En primer término, las ABR (onda V) acumuladas, evocadas por TBs sc compararon con las obtenidas usando ABRs enmascaradas con banda estrecha en sujetos jóvenes con audición normal. En segundo lugar, el método de TBs se empleó en sujetos con VSs unilaterales y en pacientes con hipoacusia unilateral en una evaluación clinica preliminar. Los resultados observados son prometedores para el uso del método de TBs como un acercamiento alternativo al “almacenamiento” de las ABRs y garantiza investigaciones adicionales y el desarrollo del método TB.