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Resume Introduction Consensus de la SFORL concernant les bonnes pratiques de la realisation d’un examen audiometrique chez l’adulte et l’enfant. Methodes Un groupe de travail multidisciplinaire a effectue une revue de la litterature. Des recommandations ont ete erigees, relues par un groupe de lecture independant du groupe de travail et finalisees lors d’une reunion de synthese. Resultats Il est recommande de realiser les examens audiometriques dans un environnement sonore maitrise (

International audience; INTRODUCTION: French Society of ENT (SFORL) good practice guidelines for audiometric examination in adults and children. METHODS: A multidisciplinary working group performed a review of the scientific literature. Guidelines were drawn up, reviewed by an independent reading group, and finalized in a consensus meeting. RESULTS: Audiometry should be performed in an acoustically controlled environment (\textless30dBA); audiometer calibration should be regularly checked; and patient-specific masking rules should be systematically applied. It should be ensured that masking is not overmasking. Adult pure-tone audiometry data should be interpreted taking account of clinical data, speech audiometry and impedancemetry. In case of discrepancies between clinical and pure-tone and speech audiometry data, objective auditory tests should be perform. In children aged 2 years or younger, subjective audiometry should be associated to behavioral audiometry adapted to the child's age. In suspected hearing impairment, behavioral audiometry should be systematically supplemented by objective hearing tests to determine and confirm the level and type of hearing impairment.

Resume L’audition en conduction osseuse implique necessairement une mise en vibration de la membrane basilaire sous l’effet d’un gradient de pression de part et d’autre de la membrane. L’onde propagee qui symbolise cette vibration de la membrane basilaire peut etre declenchee intentionnellement, lorsque l’on place le vibrateur sur la mastoide ou par inadvertance quand on teste une oreille en conduction aerienne au casque sans se preoccuper d’un passage du son a l’autre cote. Lorsque l’on teste l’audition avec un vibrateur, les chemins menant a la membrane basilaire peuvent etre distingues en deux categories principales. La premiere de ces categories court-circuite l’oreille moyenne et comporte trois mecanismes distincts : l’inertie des liquides cochleaires, la compression des parois de la cochlee et les changements de pression exerces par l’intermediaire du liquide cephalorachidien. Dans une seconde modalite, l’acces a la membrane basilaire se fait a travers l’oreille moyenne, directement ou a partir de l’oreille externe. Meme s’il n’est pas facile de quantifier avec precision la contribution de chacune de ces voies d’acces a la membrane basilaire, la conduction osseuse reste le moyen cliniquement le plus sur de tester directement la fonction de la cochlee.

SummaryBone conduction hearing inevitably involves vibration of the basilar membrane in response to a pressure gradient on either side of the membrane. The propagated wave that symbolizes this vibration of the basilar membrane can be triggered intentionally, when a bone vibrator is placed on the mastoid bone, or inadvertently when testing hearing of one ear by air conduction while disregarding transmission of the sound to the other side. When hearing is tested with a bone vibrator, the pathways leading to the basilar membrane can be divided into two main categories. The first type of pathway short-circuits the middle ear and comprises three distinct mechanisms: cochlear fluid inertia, compression of the cochlear walls, and pressure changes exerted via cerebrospinal fluid. In the second type of pathway, the stimulus reaches the basilar membrane via the middle ear, either directly or via the outer ear. Although it is difficult to precisely determine the contribution of each of these pathways to the basilar membrane, bone conduction remains the clinically most reliable way of directly testing cochlear function.

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Desde el punto de vista clinico, resulta indispensable realizar una distincion entre percepcion (o sensacion) de acufenos y el sufrimiento que causan. Esta diferenciacion se observa con claridad en los pacientes que refieren que sus molestias han aparecido mucho despues del inicio de los acufenos. La distincion tambien es util con vistas a la informacion que se ofrece al paciente, pues la mayor parte de las personas con acufenos tienen pocas o ninguna molestia. Ademas, la diferencia entre percepcion y sufrimiento hace que se interpreten con la suficiente prudencia las conclusiones extraidas de los estudios efectuados con animales, sobre todo en lo que respecta a las moleculas que pueden usarse en farmacologia y a su validacion para un uso futuro en el ser humano. En este articulo se describen los modelos fisiopatologicos de acufenos en varias categorias, comenzando por el modelo periferico, que lleva a proponer la administracion local de antagonistas de los receptores glutamatergicos N-metil-D-aspartato (NMDA). Despues se exponen los modelos integrados, primero en animales y a continuacion en el ser humano. Los modelos integrados animales hacen hincapie en el sistema nervioso central y se describen en funcion de sus caracteristicas y de las posibles aplicaciones clinicas. A continuacion se analizan y se comparan dos grandes modelos integrados clinicos, el modelo psicologico inspirado en los estudios de Hallam y el modelo neurofisiologico de Jastreboff. Se destacan especialmente las implicaciones clinicas de cada uno de ellos. Por ultimo, se presentan las condiciones metodologicas recomendadas en las investigaciones clinicas, tanto en lo que respecta a las informaciones habituales requeridas en todos los ensayos controlados como en los instrumentos de medicion especificos de los acufenos.

Annales Francaises d'Oto-Rhino-Laryngologie et de pathologie cervico-faciale - Vol. 123 - N° 6 - p. 290-295

Annales Francaises d'Oto-Rhino-Laryngologie et de pathologie cervico-faciale - Vol. 123 - N° 6 - p. 283-289

Resumen Los implantes cocleares son protesis electricas que pretenden paliar una deficiencia bilateral del oido interno, sea profunda o severa, adquirida o congenita. Contrariamente a las protesis auditivas acusticas, que actuan por medio del organo de Corti, los implantes cocleares estimulan directamente las neuronas auditivas. En muy pocas ocasiones una tecnica innovadora habia obtenido un impacto similar en el terreno de la audicion. Y, sin embargo, al desarrollo de los implantes cocleares no le faltan paradojas. Su verdadera disponibilidad, desde hace una quincena de anos solamente, ha sido recibida con entusiasmo por algunos, incredulidad e incluso hostilidad por otros. Este escepticismo era, segun las personas concernidas, de naturaleza cientifica (simplicidad de la senal electrica evaluada inconciliable con la fineza de analisis de la coclea en condiciones fisiologicas), emocional (dificultad de considerar una operacion quirurgica en un nino privado de audicion desde el nacimiento) o incluso culturales (temor de ver desaparecer la comunidad de sordos). Los trabajos suscitados desde entonces contrastan por su multiplicidad con el numero total limitado de personas implantadas en todo el mundo (menos de 30000 hasta hoy). Los beneficios demostrados por estas publicaciones son innegables, pero requieren un equipo interdisciplinario muy bien organizado, que disponga de medios materiales y, sobre todo, de medios humanos adaptados a las necesidades, particularmente en los ninos. Globalmente, se puede estimar que el desarrollo de los implantes cocleares y los resultados que se han obtenido han contribuido a un mejor conocimiento de la sordera por parte del gran publico y de los diversos organismos de asistencia, aunque hay muchos problemas pendientes. Se puede tambien esperar que los servicios a los cuales los deficientes auditivos tienen derecho aprovecharan de los progresos tecnologicos de los implantes. Estos pueden servir, de alguna manera, de «locomotora» en la lucha contra las consecuencias negativas de la sordera.

We present today our preliminary results of the TEFLAG test performed on 58 patients suffering from Meniere's disease. This test completed in 1993 has already led to a 4-stage classification of noise induced hearing losses. On the one hand, it is based on the morphological study of susceptance B curves, and on the other hand, on the study of the resonant frequency (RF) of the annular ligament of the stapes, provided by a multifrequential impedancemeter. The endolymphatic hydrops coming with the Meniere's disease practically always cohabits in the intercritical period with the decrease of the perilymphatic pressure of the scala vestibuli, which is shown in the morphology of Stage IV curves especially, and the decrease of the annular ligament rigidity. Inversely, during the vertigo or around, we mainly have stage I curves, and an increase of the stapes annular ligament resonant frequency (RF), testifying the labyrinthic hydrops, which is the physiopathological essence of the Meniere's disease.

The relationships between tinnitus and hearing loss are studied from a clinical prospect. Five critical points are discussed. 1. Some degree of hearing loss is found in the vast majority of tinnitus patients; but an individual may well have a sensorineural hearing loss and no tinnitus at all. 2. A minor adjunction to the neurophysiological model of Jastreboff is proposed to take account of the association between tinnitus and hearing loss. 3. Tinnitus appears to cause more distress when hearing loss is marked. 4. Self-reported hearing loss should be considered when implementing habituation sound therapy. 5. According to McKinney, the rate of success on tinnitus that can be expected with habituation sound therapy is not significantly affected by hearing level.

The multiple treatments of sudden deafness shows how this pathology still remains quite unknown. The authors present a retrospective study of 87 patients treated by normovolemic hemodilution associated to hyperbaric oxygenation. They obtain a total à 60% of significant recovery (ratio between hearing gain and initial hearing loss, above 25%) and in severe hearing loss (threshold between 70 and 90 dB) 60% of good results (ratio above 50%). The importance of the initial form of audiogram and the presence of dizziness as prognostic factors is not confirmed. On the other hand, the evolution of tinnitus is correlated with the deafness and it is a supplementary means to evaluate the therapeutic efficiency. Moreover the persistence of tinnitus represents an important after effect. Sudden deafness still remains a medical emergency and the delay for carrying out any treatment should be as short as possible. On the other hand it is possible to reduce hospital stay by two sessions of hyperbaric oxygenation per day.

Hyperbaric oxygen therapy is one of the numerous therapies which have been proposed in the management of sudden deafness. It is presumptuous to claim the efficiency of any treatment in a pathology where both the origin and the actual rate of spontaneous recovery are unknown. The grounds of therapies are therefore empirical but the need of urgent therapy is dictated by ethics. This study compares the effects of hyperbaric oxygen therapy in two groups of patients; according ot their order in randomization the subjects were treated either at a rate of 1 session or 2 sessions per day. Hyperbaric oxygen therapy was associated with infusion of Naftidrofuryl to counteract the vasoconstrictive effect of increased oxygen pressure in blood. Steroids were also administered simultaneously to avoid, for the same reasons, cerebral oedema. Normovolemic hemodilution (Dauman et al. 1983) was systemically performed in all the patients preliminarily to hyperbaric oxygen therapy, in order to reduce the haematocrit and thus facilitate blood supply. The efficiency and the side effects were similar in the two groups, provided that some principles in the selection and the monitoring of the patients were respected. The rate of 2 sessions of hyperbaric oxygen therapy per day has obvious advantages in view of health policy, but it requires the hospitalization of the patient and should be restricted to the younger subjects.

Stapedius reflex can provide useful prognostic information in FPs when the middle ear is normal. Its preservation may have a favorable significance in partial FP and Bell's palsy. Its loss, even though less reliable, can also have some value as an indicator for a poor prognosis in patients with total and herpes zoster FPs. Most importantly, our findings have shown that the SR alone is not sufficient to be of prognostic value, but is useful if combined with other clinical parameters and electrical responses.

The role of electrophysiology (auditory evoked potentials) in children up to 3 years old was studied through the feasibility and results of subjective audiometry. In children over six months old, subjective tests are performed systematically or at least tried before using electrophysiology. Electrophysiology is required when audiometry is impossible, and it is often performed when audiometry is abnormal. When subjective tests were not performed first, either because the child is too young or shows a developmental retardation, and the electrophysiological tests are abnormal, it is absolutely necessary to obtain an exact level of hearing as soon as possible using subjective tests. The results of a study on 244 electrophysiologically tested children between the 0 and 3 years of age are presented briefly. In 73% of the cases, the auditory brainstem responses were sufficient for clarifying or confirming the subjective tests. In 27%, they had to be completed be an electrocochleography (ECochG) under general anesthesia. The information based on the ECochG and the comparison data between the ECochG and subjective thresholds are presented. On one hand, this study highlights the double complementarity between audiometry and electrophysiology on the other, the brainstem potentials and ECochG.

A simplified method, useful in clinical practice, is described in order to study the frequency selectivity in various conditions. The patient is asked to indicate the levels of pure tones which are necessary to mask completely the perception of an intermittent probe. The resulting psychoacoustic tuning curves are characterized by a more or less narrow bandwidth which reflects the ability to resolve simultaneously presented sounds. Several circumstances where these tuning curves are helpful, are presented: assessment of tinnitus, Menière's disease, unclear impairment of speech intelligibility. Therefore, this technique appears as a valuable tool which can be used in addition to the usual audiometric and electrophysiological tests battery.

In a group of 30 adults with impaired hearing, objective thresholds defined with 40 Hz middle latency responses (MLR) were compared with subjective audiometric measures. Frequencies of 0.25, 0.5, and 1 kHz were studied. In order to guarantee a good frequency specificity, subjects presenting large high-frequency hearing loss were particularly chosen. The 40-Hz MLR thresholds were generally worse than the audiometric measures. The average difference was around 12 dB, but in about one-third of the cases it was between 20 and 30 dB. Although not perfect, 40-Hz MLR estimates on low frequencies can be very helpful and deserve further consideration, especially in children.

The technique of hemodilution was assessed in 12 cases of sudden hearing loss as it is known to improve peripheral circulation. Good results were obtained in nine patients. The immediacy of the effects suggests the real efficacy of hemodilution as opposed to spontaneous recovery. Hemodilution is supposed to improve oxygenation in the cochlea. This technique is very simple and quick to perform.

Electrical prognosis was evaluated in 79 patients with facial paralysis, of spontaneous (n = 43) or post-traumatic origin (n = 36). Three electrophysiological tests were employed jointly: detection, stimulation and stimulodetection. The patients were reviewed at least 1 year later, in order to appreciate the agreement between the electrical prognosis and the clinical outcome (satisfactory or not). Those patients with a favourable prognosis on electrical testing had in the majority of cases a satisfactory outcome. The accuracy of the prognosis was also better in cases of early examination (within 15 days) and partial paralysis.

In the majority of cases tinnitus has a high pitch and can be matched rather precisely to an objective high frequency sound. However, it is well known that tinnitus can be masked by different tones without any frequency selectivity. We wondered whether objective tones matched to tinnitus would show a more significant deterioration of frequency selectivity than could be expected from any associated hearing loss. Psychoacoustic tuning curves were obtained using simultaneous pure-tone masking and revealed a broadening of frequency selectivity. In cases of comparable bilateral hearing losses with unilateral tinnitus, the broadening associated with the tinnitus was particularly conspicuous. This broadening strongly suggests that tinnitus originates in the cochlea, although some involvement of central pathways may also occur. Tinnitus-induced broadening of frequency selectivity as a possible sign of cochlear origin deserves further consideration in future studies.

Transtympanic (TT) electrocochleography (ECochG) data recorded with click stimuli and tone bursts (1, 2, 4, and 8 kHz) were evaluated in 50 patients with Meniere's disease and compared with the data from control groups of 10 sensorineural hearing impaired patients and 5 subjects with normal hearing. The mean summating potential (SP) amplitude was larger in the Meniere's disease group for 1, 2, and 8 kHz. The low frequency (1 or 2 kHz) SP decreased in 59% of the Meniere's disease patients during a glycerol dehydration test, whereas subjective hearing improved in only 29%. The use of ECochG with the monitoring of SP thus improves the sensitivity of the glycerol test for the detection of endolymphatic hydrops. There appeared no clear relation between clinical observations and the ECochG data either before or after glycerol. However, the Meniere's disease patients with a large negative SP at low frequencies also had larger action potential (AP) and often had short-term symptoms. The present report confirms the usefulness of measuring the SP in the diagnosis of Meniere's disease.

A comparative study is undertaken in 36 cases of sudden deafness in order to appreciate the efficiency of three therapies: vaso-active drug and steroid administered through continuous perfusions, normovolemic hemodilution, and hyperbaric oxygen therapy. Groups are homogeneous with respect to age, time elapsed between onset of deafness and treatment, occurrence of vertigo, degree of hearing loss, and audiometric pattern. Results are expressed in terms of pure tone threshold improvement (dB), audiometric ratio recovery taking into account initial hearing loss, and effects upon tinnitus. These data are complemented with electrophysiological measures (click-evoked electrocochleography and auditory brainstem responses). Analysis of variance does not show significant differences among the three procedures. Mechanisms and possible usefulness are discussed, keeping in mind the difficulty of ascertaining the real efficiency of therapies with respect to spontaneous recovery.

Middle latency auditory evoked potentials can be rapidly obtained using a 40/second stimulous rate, taking advantage of response periodicity to accelerate the averaging procedure. This technique was used in 31 normally hearing adults for low frequency response evaluation. Tone pips at 250, 500, and 1000 Hz were employed. The average difference between the middle latency evoked potential threshold and the subjective threshold was 17.9 dB at 250 Hz, 14.5 dB at 500 Hz, and 13 dB at 1000 Hz. The waveform of the response and the latency and amplitude of its main peaks were also analyzed. Thresholds at 500 and 1000 Hz were also determined using brainstem evoked responses in 15 of the subjects. These differed, on average, by 30 dB from subjective thresholds. The 40 Hz MLR paradigm thus appears to be an accurate and rapid method for low frequency threshold evaluation in adults, but it is greatly influenced by the state of arousal. During sleep, response amplitude decreases and threshold increases by about 15 dB. This may be of great concern when interpreting the results in children, in whom low frequency threshold evaluation is of primary importance.

Through 14 recent cases, the authors review the main clinical syndromes leading to the diagnosis of petrous and brain-stem meningiomas. The cochleovestibular syndrome, the most frequent amongst them, recalls the symptomatology of an acoustic neuroma. The jugular foramen syndrome is similar to that seen in jugulo-tympanic paragangliomas. The middle ear tumor syndrome is specific to primary or secondary intrapetrous tumors. The positive diagnosis of meningiomas belongs to the field of CAT scares and mainly of NMR, which define morphological characters, none of them being specific: oval shape, the closed angle sign, intratumor calcification, hyperdensity, osseous changes on the posterior aspect of the petrous bone NMR permits a very precise localization and definition of the tumor which is necessary among the per-op studies. This decreases the occurrence of once frequent surgical surprises.

After the apparition of a sudden deafness, 45 patients (22 men and 23 women, with a mean age of 44 +/- 14.9 years) were treated with normovolaemic haemodilution performed with dextran 60. They were placed into 4 groups depending on their hearing loss: total loss: 10 cases; severe loss: 90 to 70 db. 13 cases; moderates loss: 65 to 40 db, 14 cases, slight loss: less than or equal to 35 db, 8 cases. The mean time between the onset of the hearing loss and treatment was 9.3 +/- 12.4 days. The initial mean haematocrit was 44.8 +/- 3.8% and mean haematocrit after haemodilution was 33.1 +/- 2.8%. For 51% of the patients, an almost total recovery was obtained. In 15.5% of cases, recovery was between 25 to 50% of the hearing loss, and in 33.3% of the patients recovery was negligible. We did not find any relationship between hearing recovery and initial haematocrit. The best results were obtained in the group of patients treated early. Hearing gain was significatively better if delay in starting treatment was less than 7 days. There was a relationship between the initial hearing loss and the final recuperation. These results suggested that haemodilution increased labyrinth microcirculation and oxygenation of the cochlear sensory cells, reversing the ischaemic insult to these cells.

Brain stem auditory-evoked responses to a 70 dB SL click masked by high-passed noises were recorded in 12 normal hearing subjects. By applying the technique of derived potentials, the contribution of one-octave-wide frequency bands are assessed. Summation of these derived potentials gives a pattern similar to the unmasked-response waveform. Waves I and III show a strong predominance of high-frequency responses, whereas wave V is discernible down to low-frequency responses.