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Biomedical subjects

N Deggouj

Publications and source records attributed to N Deggouj.

At least 19 recordsLinked to original sources

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.

Action Potentials↗

[Autistic-like behavioural disorders and deafness in children].

There is a co-morbidity between autism spectrum behaviour disorders and deafness in children. Their behavioural difficulties may appear primary and/or secondary to hearing deprivation. In this paper, we present how we manage those patients on the base of our clinical experience. The auditory assessment must be based on subjective tests taking account of their special reactions. It needs objective tests to complete and help the behavioural responses. The hearing aids amplification is increased progressively, to allow the development of a tolerance to the sounds world. The multidisciplinary team tends to open them to the world and to the communication.

Audiometry↗

[Normative study and reliability of French version of the dizziness handicap inventory].

GOAL: To determine the normality per age group of the "Echelle du Handicap lié aux Troubles de l'Equilibre et aux Vertiges" (EHTEV) French version of the "Dizziness Handicap Inventory" (DHI) and to assess the effect of sex on the scores and the reproductibility. SUBJECTS AND METHODS: The normative scores and the effect of the sex were determined in a group of 120 subjects without any instability disorder. Sixty-three women and 57 men, aged 20-79 years were graded by age section of 10 years. After 8-10 weeks the same questionnaire was submitted again to 47 individuals of this same group to assess the reproductibility. RESULTS: The scores of the instability showed that handicap increased with the age. The mean score for the 50-79 year-old group is almost four times greater that of the 20-49 years old. Correlation between scores and age is 0.70 for physical handicap, 0.76 for emotional handicap, 0.69 functional handicap and 0.83 for global score. There is no significant influence of sex. The reproductibility coefficient is 0.98. CONCLUSION: The scores of the EHTEV increase with age. There is no significant influence of sex on scores and the coefficient of the reproductibility is good. But the translation of this handicap scale, need a study of validity and reliability.

Activities of Daily Living↗

[Adolescence and cochlear implant].

During adolescence, the identity is constructed and the communication changes. The cochlear implant may disturb the identity's construction. The restrictions and advantages may be misunderstood due to the communication difficulties. It is important to take time to discuss and explain the limits of this hearing aid. It must not be perceived as a miracle resolving all auditory and oral communication problems. The hearing aid is effective for motivated and informed adolescents. The outcome depends on the level of auditory experience and oral language development before implantation. It can be very positive. (full article translated in English available on www.ent-review.com).

Adolescent↗

[Benefit of rotational exercises for patients with Meniere's syndrome, method used by the ENT department of St-Luc university clinic].

OBJECTIVE: To date, the effectiveness of balanced rehabilitation for patients with Meniere's syndrome has not been unanimously acknowledged by all physicians and physiotherapists. The purpose of this study is to assess the therapeutic efficacy of rotational exercises in the treatment of disequilibrium for patients with unilateral Meniere's syndrome. METHODOLOGY: Rotational stimuli were used to symmetrize and reduce postrotatory nystagmic response. Three reference sources were used to assess the efficacy of this management: vestibulospinal function tests: pre- and post-treatment results at the Romberg test, the Unterberger-Fukuda stepping test, the Babinski-Weil test, and gait testing with eyes closed; rotational tests: pre- and post-treatment results; and the self-perceived impact of vertigo: assessed by the Dizziness Handicap Inventory (DHI) and a scale based on the guidelines of the Japanese Society of Equilibrium Research (JSER, 1993). The JSER scale provides quantitative vertigo evaluation; the DHI reflects the patient's perceptual evaluation of handicap. RESULTS: Patients required 11 sessions (mean value) to attain subjective improvement. Of the 23 patients, only seven required optokinetic stimulation (mean requirement: three sessions). Rotational tests and dynamic tests of the vestibulospinal function improved. The DHI and JSER results show that patients' post-rehabilitation perceptual evaluation significantly improved. CONCLUSION: The objective and subjective measures of disequilibrium in patients with unilateral Meniere's syndrome were significantly improved.

Adult↗

[Primary and secondary care of cleft lip and palate in the lip-palate center in Bruxelles].

Since 1987, we chose a neonatal repair of the cleft lip and nose and closure of the cleft palate at 3 months of age. Ventilation tubes are systematically inserted in the drums at time of palatoplasty. Alveolar clefts are grafted when canine erupts. Secondary correction, which might be early, are scheduled according to functional, aesthetic or psychological demands. A interdisciplinary follow-up by a stable and united team is essential for an adequate management of sequels.

Cleft Lip↗

No evidence of auditory dysfunction in guinea pigs immunized with myelin P0 protein.

Recent data have focused on the peripheral nerve myelin glycoprotein P0 as a putative autoantigen involved in the autoimmune etiology of some cases of Meniere's disease, idiopathic sensorineural hearing loss and sudden deafness. To determine whether antibodies to myelin P0 can alter cochlear function, 13 healthy guinea pigs were immunized with purified porcine myelin P0 while 10 controls were injected with saline water. The animals were then evaluated for evidence of evolving inner ear disease using immunological, electrophysiological and morphological methods. Twenty-six experimental ears were tested weekly with a brainstem auditory evoked potential technique for a period of 4 months and were compared to 20 control ears. Uniformly, all P0-sensitized guinea pigs showed antibodies to myelin protein P0 as evidenced by ELISA. Clinical signs of inflammatory demyelination were not discernible in P0-sensitized guinea pigs and all the animals were qualitatively normal. No significant increase of evoked potential thresholds was found in the P0-sensitized animals when compared to controls (P>0.05). Peak latencies of waves I, II, III, IV and V and inter-peak latencies in P0-sensitized guinea pigs did not significantly differ from those of controls (P>0.05). Histological sections of inner ear and peripheral nerves were free of disease in both groups. These findings indicate that the sole presence of antibodies to myelin P0 in the sera of guinea pigs or patients suspected of having autoimmune inner ear diseases is unlikely to elicit auditory abnormalities and that additional factors are necessary for the pathogenic development of these disorders.

Animals↗

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

Immunological mechanisms are thought to play an important role in the pathogenesis of some cochleo-vestibular diseases. This study attempts to present further evidence of autoantibodies reactive against guinea pig inner ear proteins found in patients with autoimmune inner ear diseases (AIED) and specifically identifies the main target antigens of these antibodies. Sera from 110 patients with a clinical diagnosis of either rapidly progressive sensorineural hearing loss (n = 32). Ménière's disease (n = 41), sudden deafness (n = 6) or other aetiologies of hearing loss (n = 11) were screened by the Western blot technique. Forty-four percent of the patients' sera had antibodies to several inner ear proteins, of which the 30, 42 and 68 kDa proteins were found to be the most reactive. These highly reactive proteins were identified by gas-phase micro sequencing after digestion with trypsin and separation of peptide fragments by high-performance liquid chromatography. A partial sequence of each protein was determined. These data, together with those obtained from 2-dimensional gel electrophoresis followed by Western blotting, demonstrated that the 30 and 42 kDa inner ear proteins are the major peripheral myelin protein P0 and the beta-actin protein, respectively, while sequence analysis indicated that the 68 kDa protein is novel. These findings further support the hypothesis that several populations of antibodies may contribute to the enhanced immunological activity of AIED patients. They also add a new dimension to our knowledge of AIED and may open new avenues in the development of simple serological assays, which are easier to perform and more rapid than Western blotting.

Animals↗

Autoimmune sensorineural hearing loss in young patients: an exploratory study.

OBJECTIVES: P0 protein is expressed exclusively in myelinating Schwann cells of the peripheral nervous system. In a previous study from our laboratory, 27% of patients with sensorineural hearing loss (SNHL) had antibodies to P0 protein in their serum. The purpose of the present exploratory study was to examine the relationship between the clinical presentation of SNHL among children and young adults (age range, 5-30 y) and the presence of serum anti-P0 antibodies. STUDY DESIGN: The data were collected by retrospective questionnaires from Belgian otolaryngologists. METHODS: Patients were divided for comparison into two groups according to the presence or absence of anti-P0 antibodies. RESULTS: Analyses of clinical data and audiometric results indicated that a progressive hearing loss was more frequently recorded in the patients in the anti-P0 antibody-positive group (82% [14 of 17]) than in those in the anti-P0 antibody-negative group (35% [6 of 17]) (P <.005). CONCLUSIONS: Thus, in the age group in the present study, autoimmune SNHL (as measured in the present study by the presence of anti-P0 antibodies) is more frequently associated with progressive than with sudden hearing loss. The implications of this finding for preventive screening of hearing loss in children and young adults are discussed.

Adolescent↗

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

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

Animals↗

[Susac syndrome in a man].

The association of an acute encephalopathy, neurosensory hearing loss and retinal branch artery occlusions in a 35 year old man as well as the absence of systemic disease suggest the diagnosis of Susac's syndrome. This is the eighth male case described, the syndrome being more frequently reported in females.

Adult↗

Identification of beta-actin as a candidate autoantigen in autoimmune inner ear disease.

It has been shown that sera from patients with autoimmune inner ear disease contain antibodies to several inner ear antigens. We report here the characterization of the 42-43 kDa protein against which a significant number of patients' sera react strongly. After separation of inner ear proteins from guinea-pig cochleas by SDS-PAGE, the band corresponding to the 42-43 kDa protein was digested with trypsin and the peptide fragments were separated by high-performance liquid chromatography. Two fractions were then subjected to amino acid sequencing by the classical automated Edman degradation. The sequence of a stretch of 15 amino acids of the first fragment was identical to that of amino acids 148-162 of beta-actin. The sequence of the 10 amino acids of the second fragment was also identical to beta-actin. On Western blots, monoclonal antibody directed against beta-actin reacted with the inner ear 42-43 kDa proteins. The serum samples from the patients and the monoclonal antibody reacted with the non-muscle actin used as antigen in Western blotting. Immunoblot analysis of inner ear proteins after two-dimensional gel electrophoresis showed a spot, corresponding to the region of the 43 kDa as compared to the protein standards. On the basis of these data it is concluded that the target 42-43 kDa protein for antibodies in sera of patients with autoimmune inner ear disease is beta-actin, a molecule, which has important and numerous functions inside cells. This is the first report to identify the cytoskeletal protein beta-actin as a candidate autoantigen in autoimmune inner ear disease.

Actins↗

[Functional results of velopharyngoplasty: apropos of 55 cases].

From 1991 until 1998, 55 three to twelve year-old patients underwent a velopharyngoplasty to correct velopharyngeal insufficiency. They had indeed severe hypernasality with or without gross reflux of food matter into the nasal cavities or behavioural disturbances. Eighty-two percent had a closed cleft palate. Forty percent presented with mental retardation, heart diseases or multiple syndromal defects. They all had had a previous speech therapy for a long (months) or a very long (years) period of time. In the post operative period, hypernasality disappeared totally or partially in eighty-five percent; reflux disappeared in almost all cases. Middle ear pathologies were not more frequent and were also less severe. Behavioral disturbances associated with a severe speech defect were also less pronounced.

Age Factors↗

Imaging and cochlear implant.

The auditory pathway imaging may be morphologic and/or functional. The high resolution computed tomography and the magnetic resonance imaging (MRI) provide an evaluation of the anatomical and structural landmarks useful for a safe and successful cochlear implantation. The electrical stimulations supplied by the cochlear implant give rise to ascending electrochemical activities reaching the cortex. These activities can be recorded with scalp electrodes by Evoked Potentials (EP) or fields techniques and eventually translated in isochronic or isopotential brain mapping. These techniques provide a very sharp temporal resolution with an imprecise spatial resolution. The late auditory EP of implantees are closely comparable to the responses of normal hearing people. The neuronal metabolism's increase is associated with a cerebral blood flow increase. Comparing regional cerebral blood flow (rCBF) between two or more conditions allows the localisation of brain areas involved in a fixed task. Single photon or positron emission tomography and functional MRI (fMRI) demonstrate cBF changes associated with an auditory stimulation. (f)MRI is contraindicated in cochlear implantees.

Brain↗

Role of speech therapy and sign language prior to cochlear implantation.

The speech therapist should assess and develop the communication skills of the deaf child prior and after a cochlear implantation. The goals are first the acquisition of a useful communication system by the deaf child (for avoiding a cognitive stimulation lack) and parallely the acquisition of good oral language competencies. The different modes of communication useable in the profoundly deaf education are presented. Exclusive sign language use is not indicated in implanted children. It is well demonstrated that an exclusive oral communication is associated with an insufficient knowledge of the oral language. The total communication (combination of listening, speech reading, signing with or without finger spelling) is a defective communication mode with a bad representation of the morpho-syntactic and the phonologic aspects of the oral language. The best choice seems to be the simultaneously use of a spoken language and a manually coding of their phonological structures. The limits of this alternative are discussed.

Child↗

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

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

Adult↗

Intracochlear schwannoma.

In the case reported evaluation of unilateral endocochlear deafness in a 44-year-old man led to a diagnosis of a small intracanalicular neurinoma of the cochlear nerve which had invaded the first turn of the cochlear spiral.

Adult↗