1,721,022 research outputs found
Connexin26 deafness is not always congenital
No full textOBJECTIVE:
Hearing loss associated with mutations of the GJB2, the gene encoding Connexin 26 (Cx26), is described as a prelingual, bilateral, prevalently stable sensorineural defect ranging in severity from mild to profound. Despite many clinical studies, there is still a limited knowledge about the severity of Cx26 hearing loss at birth, in the postnatal period or in early infancy; some authors have reported about a possible variable age of onset. The aim of this work was to investigate the characteristics of Cx26 hearing loss and test the hypothesis of a postnatal sudden and severe deterioration of the hearing capacity in cases with uncertain age at onset.
METHODS:
We have studied 79 children with molecularly documented biallelic Cx26 hearing loss by evaluating longitudinal audiometric characteristics and the results of a questionnaire administered to the parents, regarding the auditory behavior of their children at 3 and 6 months of age.
RESULTS:
More than 50% of children with profound hearing loss were described as having normal auditory behavior at three months of age, and at least 20% of these children were consistently reported by the parents to maintain normal auditory development up to 6 months of age. None of the studied children showed significant progression in hearing loss from the time of diagnosis through their last follow-up. In a few cases these reports were supported by objective audiometric evaluations.
CONCLUSIONS:
Based on these data, we hypothesize that Cx26 profound hearing loss may be not always congenital, with the possibility of an early window of "functional time" before the final defect is established. The hypothesis of an early auditory input makes timing of detection and intervention critical to minimize the deleterious effects of a functional deprivation. In a near future, the combination of genetic testing with universal neonatal hearing screening and audiological surveillance will provide invaluable information about the natural history of the most frequent sensory defect in infancy and will consequently allow to maximize the quality of intervention
Audiological Management of Noise Induced Hearing Loss
No full textNoise-induced hearing loss (NIHL) has no specific of exclusive audiological signs. The disorder is identified on the strength of a high probability conclusion and as a result of an exclusion process. Because of frequent legal purposes, audiometrical data measured and analyzed have furthermore to be as accurate and reliable as possible. The paper outlines the whole procedure involved in the audiological assessment of noise-induced hearing loss considering different stages for: suspicion and identification, hearing threshold measurement, etiological and differential diagnosis, apportionmen
Mutazioni DFNB1 e Ipoacusia Neurosensoriale non Sindromica: Genetica e Caratteristiche Cliniche
No full textL’ipoacusia è il più frequente fra i difetti neurosensoriali nell’uomo; l’impatto di questo deficit funzionale è tanto maggiore quanto più severa la perdita uditiva e quanto più precocemente questa si instaura. Un’ipoacusia severa o profonda presente alla nascita, se non diagnosticata in epoca molto precoce, può seriamente compromettere l’acquisizione del linguaggio e tradursi in un handicap cronico che nonostante le moderne tecniche riabilitative è spesso di difficile gestione. Questo costituisce un problema di largo impatto sociale, se si considera una frequenza di 1-2 bambini sordi su mille nati.
Un origine genetica è probabilmente alla base del difetto uditivo in più della metà di tutti i casi di ipoacusia congenita o comunque preverbale. Esistono almeno 300 sindromi note associate ad ipoacusia, ma le forme in assoluto più frequenti sono le ipoacusie isolate, quelle nelle quali il deficit uditivo è l’unica caratteristica clinica riscontrabile. Queste rappresentano almeno il 70% di tutte le forme ereditarie e vengono trasmesse prevalentemente come autosomiche recessive. Grandissima è l’eterogeneità genetica nell’ambito dell’ipoacusia, attualmente sono noti almeno 75 loci per altrettante forme di ipoacusia ereditaria non sindromica e 36 “geni-malattia” sono stati identificati
Acoustic distortion products otoacustic emissions (DPOAE) in neonatal screening
No full textThe purpose of the work was to determine the feasibility of direct nursery DPOAE testing in a universal hearing screening, evaluate the results and calculate the reliability of this test vs. Auditory Brainstem Responses (ABR). To this purpose DPOAE (sweep and I/O test) were performed on 500 children born between January and August 1996 at the Civil Hospital of Mestre, Italy. All the children were examined in the nursery, no matter what the risk factors or specific motivations. Besides determining whether the examination could be performed, its specificity and sensitivity, the time required and any variation depending on the day of testing were also evaluated. In a high percentage of cases (11.2%) it proved impossible to perform the test. In addition, when compared to ABR, the percentage of false positives was rather high (16.2%) and specificity was 84%. As conceived, the test requires 6'09" per ear. Comparison of the differences in results according to day of execution did not appear significant although there was a lower percentage of false positive after the third day of life. DPOAE can be measured in the nursery. The high number of false positives and the frequent need to repeat the measurements, however, increase the amount of time required for this test, thus voiding any time savings over an ABR screening: a test which is rather lengthy by provides a high degree of specificity
Speech perception test in Italian language for profound deaf children
No full textSpeech perception tests are an important part of procedures for diagnosing pre-verbal hearing loss. Merely establishing a child's hearing threshold with and without a hearing aid is not sufficient to ensure an adequate evaluation with a view to selecting cases suitable for cochlear implants because it fails to indicate the real benefit obtained from using a conventional hearing aid reliably. Speech perception tests have proved useful not only for patient selection, but also for subsequent evaluation of the efficacy of new hearing aids, such as tactile devices and cochlear implants. In clinical practice, the tests most commonly adopted with small children are: The Auditory Comprehension Test (ACT), Discrimination after Training (DAT), Monosyllable, Trochee, Spondee tests (MTS), Glendonald Auditory Screening Priocedure (GASP), Early Speech Perception Test (ESP), Rather than considering specific results achieved in individual cases, reference is generally made to the four speech perception classes proposed by Moog and Geers of the CID of St. Louis. The purpose of this classification, made on the results obtained with suitably differentiated tests according to the child's age and language ability, is to detect differences in perception of a spoken message in ideal listening conditions. To date, no italian language speech perception test has been designed to establish the assessment of speech perception level in children with profound hearing impairment. We attempted, therefore, to adapt the existing English tests to the Italian language taking into consideration the differences between the two languages. Our attention focused on the ESP test since it can be applied to even very small children (2 years old). The ESP is proposed in a standard version for hearing-impaired children over the age of 6 years and in a simplified version for younger children. The rationale we used for selecting Italian words reflect the rationale established for the original version, but the choice of single words follows different criteria from the original version. In fact, the two languages differ in important linguistic features so that the test can not be not adapted to the Italian language by simply translating the words involved. As currently there is no children's language dictionary in Italian arranged according to age bracket, we chose words used in children and in pre-school reading material
Caratteristiche sociali di un gruppo di adolescenti ipoacusici frequentanti una scuola statale per sordi: una indagine esplorativa
No full text
Compound action potential (CAP) and cochlear microphonic (CM) extracted from electrocochleographic responses to condensation or rarefaction clicks
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