Functional analysis of R75Q mutation in the gene coding for Connexin 26 identified in a family with nonsyndromic hearing loss.

Mutations in the gene (GJB2) coding for Connexin 26 (Cx26) are responsible for genetic forms of sensorineural hearing loss. This article describes a family characterized by congenital profound hearing loss, inherited in an autosomal dominant fashion and associated to a R75Q substitution in Cx26. Cell transfection and fluorescence imaging, dye transfer experiments and dual patch clamp recording showed that the mutant completely prevents the formation of functional channels despite assembling into junctional plaques, in communication incompetent HeLa cells. The disease is not associated with palmar and plantar keratosis in any of the family members, suggesting that R75Q substitution is not sufficient for the development of the complete syndromic phenotype. The association of palmar and plantar keratosis with profound hearing loss may be dependent on genetic background, requiring a functional interaction between the mutated Cx26 and other epidermally expressed connexins.

Multidimensional Voice Program (MDVP) and amplitude variation parameters in euphonic adult subjects. Normative study.

The introduction, in the late 70s, of the first digital spectrograph (DSP Sonograph) by Kay Elemetrics has improved the possibilities of spectroacoustic voice analysis in the clinical field. Thanks to the marketing, in 1993, of the Multi Dimensional Voice Program (MDVP) advanced system, it is now possible to analyse 33 quantitative voice parameters which, in turn, allow evaluation of fundamental frequency, amplitude and spectral energy balance and the presence of any sonority gap and diplophony. Despite its potentials, the above-mentioned system is not widely used yet, partly on account of the lack of a standard procedure. Indeed, there are still only a few case reports in the literature taking into consideration prescriptive aspects related both to procedure and analysis. This study aims to provide the results of amplitude perturbation parameter analysis in euphonic adult patients. In our opinion, these are the most significant parameters in determining the severity of a phonation disorder. The study has been carried out on 35 patients (24 female, 11 male, mean age 31.6 years, range 19-59). The voice signal has been recorded using a 4300 B Kay Computer Speech Lab (CSL) supported by a personal computer including a SM48 Shure-Prolog microphone located at a distance of 15 cm and angled at 45 degrees. Input microphone saturation has been adjusted to 6/9 of the CH1 channel. The voice sample consisted in a held /a/ and the analysis has been carried out on the central 3 seconds of the recording. The analysis has been carried out using a 5105 MDVP software version 2.3 and the signal digitalised at a 50 kHz sample rate. In order for the sample to be as free from intensity or frequency changes as possible, each patient underwent a training session (including at least 3 phonation tests) before the recording. The study included only emissions between 55 and 65 dB and with spectrum stability. Environmental noise has constantly been monitored and maintained below 30 dB. Data from the 24 female patients showed: absolute Shimmer (ShdB) = 0.203 dB, relative shimmer (Shim %) = 2.226, amplitude perturbation quotient (APQ) = 1.758, smoothed amplitude perturbation quotient = 3.309, peak amplitude variation (vAm) = 7.042. Data from the 11 males showed: absolute Shimmer (ShdB) = 0.269 dB, relative shimmer (Shim %) = 2.892, amplitude perturbation quotient (APQ) = 2.611, smoothed amplitude perturbation quotient (SAPQ) = 3.433, peak amplitude variation (vAm) = 6.385. Statistical analysis (t test) showed no statistically significant difference between sexes, thus a single set of rules was used for both sexes.

Development of communication and speech skills after cochlear implant in a sign language child.

In selecting patients to undergo cochlear implant, a pre-existing use of sign language gives rise to two problems that have been widely debated in the literature. First, the caution shown toward the candidacy of patients using this mode of communication, since it is considered a possible element of interference in the acquisition of speech. Secondly, refusal of the cochlear implant procedure, on the part of the deaf community, on the grounds both of cultural identity and of it being more "natural" for a deaf person to use an unimpaired visual channel rather than an impaired hearing channel. In order to establish whether knowledge of sign language does, indeed, affect speech production negatively and evaluate which mode of communication, oral or gestual, is preferred, the present investigation was carried out on a preverbal deaf child who had undergone cochlear implant at about 7 years of age and has always used both languages. His verbal skills were evaluated in the precochlear implant stage, then at 6 and 12 months after, together with the changes in his use of sign language and in the relationship between the two modes. Results, besides observing the presence of linguistic evolution at each level examined and already evident at 6 months, also documented a progressive reduction in the spontaneous use of sign language. In conclusion, the present experience revealed no temporal or qualitative differences in post-cochlear implant evolution of speech skills, in comparison with that observed in patients with an exclusively aural-oral approach. Furthermore, the increased use of the hearing pathway, made possible by cochlear implant, determined a spontaneous choice of verbal language as the most natural and economic mode of communication.

Changes in clinical and instrumental vestibular parameters following acute exposition to auditory stress.

Besides Tullio's phenomenon, resulting from anatomic changes in the labyrinth, a hypersensitivity to acoustic stimuli of the saccular structures appears to be the underlying cause of the vestibular responses detected in some patients. In order to evaluate the incidence of vestibular symptoms triggered by acute exposure to auditory stress (disco music), 40 subjects aged between 18 and 26 years, with no audiological and vestibular disorders, were submitted to otoneurologic tests. Subjects were exposed to disco music [intensity 128 dB (C)], for 3 hours. Tests have been carried out before and immediately after exposure. Canalar and macular functions have been evaluated using vestibular investigation techniques and vestibular evoked myogenic potentials. When compared to baseline data, post-exposure test results did not reveal any canalar damage. Pre- and post-exposure recordings of the vestibular-oculomotor reflex threshold have shown no significant changes. Conversely, post-stimulus recordings have shown a significant increase in the amplitude of the vestibular evoked myogenic potential response, thus indicating a possible irritative involvement of the macular receptor. This result suggests a direct action upon the receptor by acoustic stimulation which could, therefore, be the underlying cause of vestibular symptoms reported by patients following exposure to sufficiently intense acoustic stimuli. Prior to this study. a questionnaire concerning the relationship between habitual disco visiting and audio-vestibular symptoms has been completed by 310 students at the University of Catanzaro. This survey revealed a significant incidence of vestibular symptoms due to acoustic stress (Tullio's phenomenon) which led us to hypothesise that balance disorders due to auditory stress are much more frequent than commonly held, particularly since, in many cases, diagnoses is unknown or not easy due to the difficult procedures by which these conditions are diagnosed.

Comparison of SPT and NPT in the ascertainment of nasal mucosa as shock organ.

The Skin Prick Test (SPT) is the principal tool in allergic diagnosis, but in allergic rhinitisan immunological disease which affects 12% of the total population-the Nasal Provocation Test (NPT) allows more reliable results to be obtained. In our study a positive response to NPT has been found in four subjects with a history of symptoms suggesting allergic rhinitis, who had a negative SPT. Subjects with a positive SPT for two or more inhalant antigens have a significantly reduced number of antigen responses to NPT. Moreover, in two cases, the antigen than induced a positive response to NPT was different from the antigen that induced positive SPT. So. NPT is a reliable way of diagnosing allergic rhinitis. A more specific and reliable ascertainment of the antigen responsible for allergic reaction avoids unnecessary and ineffective immunotherapeutical attempts based on false assumptions.