Estudo dos limiares de audibilidade nas altas frequências em trabalhadores da área odontológica

INTRODUÇÃO: Na prática odontológica, o Cirurgião-Dentista está sujeito aos efeitos nocivos provocados por diversos agentes, como pelo ruído emitido por seus instrumentos de trabalho. Em 1959, a American Dental Association recomendava avaliações audiométricas periódicas e uso de proteção auditiva. São necessárias maiores informações sobre o comportamento auditivo dessa população: Cirurgiões-Dentistas, Auxiliares e Protéticos para se propor medidas de prevenção e tratamento precoce. OBJETIVO: Investigar os limiares de audibilidade em Cirurgiões-Dentistas, Auxiliares e Protéticos. MÉTODO: Forma de estudo: Estudo Clínico.Participaram 108 profissionais, sendo 44 Cirurgiões-Dentistas (GI), 36 Auxiliares (G II) e 28 Protéticos (GIII). Foram realizadas: entrevista específica, meatoscopia, audiometria tonal convencional e de altas frequências, logoaudiometria, imitanciometria. RESULTADOS: A comparação entre as médias dos limiares evidenciaram piora com o aumento da frequência para os 3 grupos testados; para a média tritonal de 500 a 2000Hz, e 3000 a 6000 Hz, o GIII apresentou os piores limiares, já para a média das altas frequências (9000 a 16.000Hz) o GII apresentou os piores limiares. CONCLUSÃO: A avaliação audiológica convencional não identificou exames alterados para os três grupos testados, no entanto, o exame da avaliação audiológica complementar como a audiometria de altas frequências indicou maior sensibilidade na detecção precoce de alterações auditivas uma vez que a perda auditiva dessa população acomete as frequências que não são testadas nos exames convencionais. Dessa maneira enfatizamos nesse trabalho a necessidade de inserir na rotina de exames a audiometria de altas frequências juntamente com os outros exames audiológicos.

BAHA (Bone Anchored Hearing Aid) indicações, resultados funcionais e comparação com cirurgia reconstrutiva de orelha

INTRODUÇÃO: O BAHA (Bone Ancored Hearing Aid) é um dispositivo auditivo de condução óssea que propaga o som diretamente à orelha interna, utilizado principalmente em pacientes com perda auditiva condutiva associada a atresia aural, mas atualmente também em perdas mistas e neurossensoriais. OBJETIVO: Revisar as principais indicações do BAHA, analisar os resultados audiométricos e os benefícios proporcionados aos pacientes, e compará-los com outras modalidades de tratamento além de comparar os dados da literatura com nossa casuística de 13 pacientes. MÉTODO: A pesquisa foi realizada em bases de dados abrangendo trabalhos em inglês, espanhol e português, sem limites de intervalos de anos, comparando com os resultados dos nossos 13 pacientes submetidos a esse procedimento, no período de 2000 a 2009. RESULTADOS: A maioria dos trabalhos mostrou vantagens do BAHA em comparação à cirurgia reconstrutiva, tanto pelos resultados audiológicos quanto em relação a complicações e recidiva. Os resultados pós-operatórios nos 13 pacientes operados por nossa equipe foi satisfatório e compatível com os da literatura, com fechamento do gap aéreo-ósseo em 7 pacientes e gap aéreo-ósseo de até 10 dB em 6 pacientes. Não houve complicações pós-operatórias. CONCLUSÃO: O BAHA é uma ótima opção de tratamento para pacientes com surdez condutiva bilateral, fato demonstrado pelos bons resultados audiológicos e por se tratar de um procedimento cirúrgico relativamente simples e com baixa taxa de complicações. Os estudos mais recentes vêm abordando seu uso para surdez condutiva e neurossensorial unilateral.

O uso de um software na (re)habilitação de crianças com deficiência auditiva

OBJETIVO: Verificar a aplicabilidade de um software na (re)habilitação de crianças com deficiência auditiva. MÉTODOS: A amostra foi composta por 17 crianças com deficiência auditiva, sendo dez usuárias de Implante Coclear (IC) e sete usuárias de Aparelho de Amplificação Sonora Individual (AASI). Foi utilizado o "Software Auxiliar na Reabilitação de Distúrbios Auditivos (SARDA)". Aplicou-se o protocolo de treinamento durante 30 minutos, duas vezes por semana, pelo tempo necessário para a finalização das estratégias que compõe software. Para mensurar a aplicabilidade do software no treinamento da habilidade de percepção da fala no silêncio e no ruído, foram realizadas avaliações com o Hearing in Noise Test (HINT) pré e pós o treinamento auditivo. Os dados foram analisados estatisticamente. RESULTADOS: O grupo de usuários de IC necessitou em média 12,2 dias para finalizar as estratégias e o grupo de usuários de AASI em média 10,14 dias. Os dois grupos apresentaram diferença entre as avaliações pré e pós no silêncio e no ruído. As crianças mais novas apresentaram maior dificuldade durante a execução das estratégias, porém não houve correlação entre a idade e o desempenho. Não houve influência do tipo do dispositivo eletrônico durante o treinamento. As crianças apresentaram maior dificuldade na estratégia que envolvia estímulos não verbais e na estratégia com estímulos verbais que treina a habilidade de atenção sustentada. A atenção e a motivação da criança durante a estimulação foram fundamentais para o bom rendimento do treinamento auditivo. CONCLUSÃO: O treinamento auditivo com o SARDA foi eficaz, pois propiciou melhora na habilidade de percepção da fala, no silêncio e no ruído, das crianças com deficiência auditiva.

Survey of hearing disorders in an urban population in Rondonia, Northern Brazil

OBJECTIVE: To identify the prevalence of hearing loss for the population in the urban area. METHODS: A cross-sectional household survey based on the World Health Organization Ear and Hearing Disorders Survey Protocol was conducted in 298 households in the urban area of Monte Negro, Rondonia, Northern Brazil, from 2005 to 2007. Ear examinations, behavioral audiometry and pure tone audiometry were conducted on 577 individuals. RESULTS: The results showed that 3.8% (95%CI 2.17;5.45) of population were classifi ed in the disabling hearing impairment category. The prevalence of moderate hearing impairment was 3.4%; severe impairment was 0.4%; and profound hearing impairment was not found. CONCLUSIONS: The impairing hearing loss prevalence found in this study is within of the international prevalence for this level of hearing loss and smaller than observed in a previous study in the South region of Brazil.

Design of a semi-implantable hearing device for direct acoustic cochlear stimulation

A new hearing therapy based on direct acoustic cochlear stimulation was developed for the treatment of severe to profound mixed hearing loss. The device efficacy was validated in an initial clinical trial with four patients. This semi-implantable investigational device consists of an externally worn audio processor, a percutaneous connector, and an implantable microactuator. The actuator is placed in the mastoid bone, right behind the external auditory canal. It generates vibrations that are directly coupled to the inner ear fluids and that, therefore, bypass the external and the middle ear. The system is able to provide an equivalent sound pressure level of 125 dB over the frequency range between 125 and 8000 Hz. The hermetically sealed actuator is designed to provide maximal output power by keeping its dimensions small enough to enable implantation. A network model is used to simulate the dynamic characteristics of the actuator to adjust its transfer function to the characteristics of the middle ear. The geometry of the different actuator components is optimized using finite-element modeling.

Surgery for the bone-anchored hearing aid

This review covers the surgery for the bone-anchored hearing aid (Baha(®)). PREOPERATIVE WORKUP: A review of the indications and preoperative diagnostics shows that best results are generally obtained in patients with conductive or mixed hearing loss rehabilitation when surgery is not applicable or has failed and in patients that suffer from single-sided deafness. An audiogram must confirm that the bone conduction hearing is within the inclusion criteria. A computed tomography scan is performed in cases of malformation to assure sufficient bone thickness at the site of screw implantation.

Does quantification of USPIO uptake-related signal loss allow differentiation of benign and malignant normal-sized pelvic lymph nodes?

Ultrasmall superparamagnetic iron oxide (USPIO) particles are promising contrast media, especially for molecular and cellular imaging besides lymph node staging owing to their superior NMR efficacy, macrophage uptake and lymphotropic properties. The goal of the present prospective clinical work was to validate quantification of signal decrease on high-resolution T(2)-weighted MR sequences before and 24-36 h after USPIO administration for accurate differentiation between benign and malignant normal-sized pelvic lymph nodes. Fifty-eight patients with bladder or prostate cancer were examined on a 3 T MR unit and their respective lymph node signal intensities (SI), signal-to-noise (SNR) and contrast-to-noise (CNR) were determined on pre- and post-contrast 3D T(2)-weighted turbo spin echo (TSE) images. Based on histology and/or localization, USPIO-uptake-related SI/SNR decrease of benign vs malignant and pelvic vs inguinal lymph nodes was compared. Out of 2182 resected lymph nodes 366 were selected for MRI post-processing. Benign pelvic lymph nodes showed a significantly higher SI/SNR decrease compared with malignant nodes (p < 0.0001). Inguinal lymph nodes in comparison to pelvic lymph nodes presented a reduced SI/SNR decrease (p < 0.0001). CNR did not differ significantly between benign and malignant lymph nodes. The receiver operating curve analysis yielded an area under the curve of 0.96, and the point with optimal accuracy was found at a threshold value of 13.5% SNR decrease. Overlap of SI and SNR changes between benign and malignant lymph nodes were attributed to partial voluming, lipomatosis, histiocytosis or focal lymphoreticular hyperplasia. USPIO-enhanced MRI improves the diagnostic ability of lymph node staging in normal-sized lymph nodes, although some overlap of SI/SNR-changes remained. Quantification of USPIO-dependent SNR decrease will enable the validation of this promising technique with the final goal of improving and individualizing patient care.

A Novel Implantable Hearing System with Direct Acoustic Cochlear Stimulation

A new implantable hearing system, the direct acoustic cochlear stimulator (DACS) is presented. This system is based on the principle of a power-driven stapes prosthesis and intended for the treatment of severe mixed hearing loss due to advanced otosclerosis. It consists of an implantable electromagnetic transducer, which transfers acoustic energy directly to the inner ear, and an audio processor worn externally behind the implanted ear. The device is implanted using a specially developed retromeatal microsurgical approach. After removal of the stapes, a conventional stapes prosthesis is attached to the transducer and placed in the oval window to allow direct acoustical coupling to the perilymph of the inner ear. In order to restore the natural sound transmission of the ossicular chain, a second stapes prosthesis is placed in parallel to the first one into the oval window and attached to the patient's own incus, as in a conventional stapedectomy. Four patients were implanted with an investigational DACS device. The hearing threshold of the implanted ears before implantation ranged from 78 to 101 dB (air conduction, pure tone average, 0.5-4 kHz) with air-bone gaps of 33-44 dB in the same frequency range. Postoperatively, substantial improvements in sound field thresholds, speech intelligibility as well as in the subjective assessment of everyday situations were found in all patients. Two years after the implantations, monosyllabic word recognition scores in quiet at 75 dB improved by 45-100 percent points when using the DACS. Furthermore, hearing thresholds were already improved by the second stapes prosthesis alone by 14-28 dB (pure tone average 0.5-4 kHz, DACS switched off). No device-related serious medical complications occurred and all patients have continued to use their device on a daily basis for over 2 years. Copyright (c) 2008 S. Karger AG, Basel.

A two-microphone noise reduction system for cochlear implant users with nearby microphones. Part I: Signal processing algorithm design and development

Users of cochlear implant systems, that is, of auditory aids which stimulate the auditory nerve at the cochlea electrically, often complain about poor speech understanding in noisy environments. Despite the proven advantages of multimicrophone directional noise reduction systems for conventional hearing aids, only one major manufacturer has so far implemented such a system in a product, presumably because of the added power consumption and size. We present a physically small (intermicrophone distance 7 mm) and computationally inexpensive adaptive noise reduction system suitable for behind-the-ear cochlear implant speech processors. Supporting algorithms, which allow the adjustment of the opening angle and the maximum noise suppression, are proposed and evaluated. A portable real-time device for test in real acoustic environments is presented.

Bone-anchored Hearing Aids: correlation between pure-tone thresholds and outcome in three user groups

OBJECTIVE: To investigate correlations between preoperative hearing thresholds and postoperative aided thresholds and speech understanding of users of Bone-anchored Hearing Aids (BAHA). Such correlations may be useful to estimate the postoperative outcome with BAHA from preoperative data. STUDY DESIGN: Retrospective case review. SETTING: Tertiary referral center. PATIENTS:: Ninety-two adult unilaterally implanted BAHA users in 3 groups: (A) 24 subjects with a unilateral conductive hearing loss, (B) 38 subjects with a bilateral conductive hearing loss, and (C) 30 subjects with single-sided deafness. INTERVENTIONS: Preoperative air-conduction and bone-conduction thresholds and 3-month postoperative aided and unaided sound-field thresholds as well as speech understanding using German 2-digit numbers and monosyllabic words were measured and analyzed. MAIN OUTCOME MEASURES: Correlation between preoperative air-conduction and bone-conduction thresholds of the better and of the poorer ear and postoperative aided thresholds as well as correlations between gain in sound-field threshold and gain in speech understanding. RESULTS: Aided postoperative sound-field thresholds correlate best with BC threshold of the better ear (correlation coefficients, r2 = 0.237 to 0.419, p = 0.0006 to 0.0064, depending on the group of subjects). Improvements in sound-field threshold correspond to improvements in speech understanding. CONCLUSION: When estimating expected postoperative aided sound-field thresholds of BAHA users from preoperative hearing thresholds, the BC threshold of the better ear should be used. For the patient groups considered, speech understanding in quiet can be estimated from the improvement in sound-field thresholds.

Radiological factors related to pre-operative hearing levels in patients with vestibular schwannomas

The pathogenetic mechanism of hearing loss in patients with vestibular schwannomas (VS) remains unclear. Our aim was to determine the radiological and clinical parameters that might be related to hearing. The radiological images and charts of 99 patients were reviewed. Image processing software was used to analyse the maximal tumor diameter in three planes; its volume; its extension cranially, caudally, anteriorly and posteriorly; the width and length of the intrameatal tumor portion, its shape and consistency; and the tumor-fundus distance. These parameters were correlated with the patient's pre-operative hearing range. The degree of hearing correlated significantly with the tumor size, volume and coronal diameter, the degree of intrameatal tumor growth, and the distance between the lateral tumor end and the fundus (p < 0.05). No correlation was found regarding tumor extension, shape and consistency, the presence of hydrocephalus, or the extent of erosion of the internal auditory canal. Loss of hearing in the VS appears to be multifactorial. Determining the radiological parameters related to the hearing level can help to clarify the pathophysiological mechanisms involved.

Influence of directionality and maximal power output on speech understanding with bone anchored hearing implants in single sided deafness

Bone-anchored hearing implants (BAHI) are routinely used to alleviate the effects of the acoustic head shadow in single-sided sensorineural deafness (SSD). In this study, the influence of the directional microphone setting and the maximum power output of the BAHI sound processor on speech understanding in noise in a laboratory setting were investigated. Eight adult BAHI users with SSD participated in this pilot study. Speech understanding in noise was measured using a new Slovak speech-in-noise test in two different spatial settings, either with noise coming from the front and noise from the side of the BAHI (S90N0) or vice versa (S0N90). In both spatial settings, speech understanding was measured without a BAHI, with a Baha BP100 in omnidirectional mode, with a BP100 in directional mode, with a BP110 power in omnidirectional and with a BP110 power in directional mode. In spatial setting S90N0, speech understanding in noise with either sound processor and in either directional mode was improved by 2.2-2.8 dB (p = 0.004-0.016). In spatial setting S0N90, speech understanding in noise was reduced by either BAHI, but was significantly better by 1.0-1.8 dB, if the directional microphone system was activated (p = 0.046), when compared to the omnidirectional setting. With the limited number of subjects in this study, no statistically significant differences were found between the two sound processors.

Benefit of a Contralateral Routing of Signal Device for Unilateral Cochlear Implant Users.

Objective: To investigate objective and subjective effects of an adjunctive contralateral routing of signal (CROS) device at the untreated ear in patients with a unilateral cochlear implant (CI). Design: Prospective study of 10 adult experienced unilateral CI users with bilateral severe-to-profound hearing loss. Speech in noise reception (SNR) and sound localization were measured with and without the additional CROS device. SNR was measured by applying speech signals at the untreated/CROS side while noise signals came from the front (S90N0). For S0N90, signal sources were switched. Sound localization was measured in a 12-loudspeaker full circle setup. To evaluate the subjective benefit, patients tried the device for 2 weeks at home, then filled out the abbreviated Speech, Spatial and Qualities of Hearing Scale as well as the Bern benefit in single-sided deafness questionnaires. Results: In the setting S90N0, all patients showed a highly significant SNR improvement when wearing the additional CROS device (mean 6.4 dB, p < 0.001). In the unfavorable setting S0N90, only a minor deterioration of speech understanding was noted (mean -0.66 dB, p = 0.54). Sound localization did not improve substantially with CROS. In the two questionnaires, 12 of 14 items showed an improvement in mean values, but none of them was statistically significant. Conclusion: Patients with unilateral CI benefit from a contralateral CROS device, particularly in a noisy environment, when speech comes from the CROS ear side. © 2014 S. Karger AG, Basel.

Comprehensive measures of sound exposures in cinemas using smart phones

OBJECTIVES Sensorineural hearing loss from sound overexposure has a considerable prevalence. Identification of sound hazards is crucial, as prevention, due to a lack of definitive therapies, is the sole alternative to hearing aids. One subjectively loud, yet little studied, potential sound hazard is movie theaters. This study uses smart phones to evaluate their applicability as a widely available, validated sound pressure level (SPL) meter. Therefore, this study measures sound levels in movie theaters to determine whether sound levels exceed safe occupational noise exposure limits and whether sound levels in movie theaters differ as a function of movie, movie theater, presentation time, and seat location within the theater. DESIGN Six smart phones with an SPL meter software application were calibrated with a precision SPL meter and validated as an SPL meter. Additionally, three different smart phone generations were measured in comparison to an integrating SPL meter. Two different movies, an action movie and a children's movie, were measured six times each in 10 different venues (n = 117). To maximize representativeness, movies were selected focusing on large release productions with probable high attendance. Movie theaters were selected in the San Francisco, CA, area based on whether they screened both chosen movies and to represent the largest variety of theater proprietors. Measurements were analyzed in regard to differences between theaters, location within the theater, movie, as well as presentation time and day as indirect indicator of film attendance. RESULTS The smart phone measurements demonstrated high accuracy and reliability. Overall, sound levels in movie theaters do not exceed safe exposure limits by occupational standards. Sound levels vary significantly across theaters and demonstrated statistically significant higher sound levels and exposures in the action movie compared to the children's movie. Sound levels decrease with distance from the screen. However, no influence on time of day or day of the week as indirect indicator of film attendance could be found. CONCLUSIONS Calibrated smart phones with an appropriate software application as used in this study can be utilized as a validated SPL meter. Because of the wide availability, smart phones in combination with the software application can provide high quantity recreational sound exposure measurements, which can facilitate the identification of potential noise hazards. Sound levels in movie theaters decrease with distance to the screen, but do not exceed safe occupational noise exposure limits. Additionally, there are significant differences in sound levels across movie theaters and movies, but not in presentation time.

Is complex signal processing for bone conduction hearing aids useful?

OBJECTIVES To establish whether complex signal processing is beneficial for users of bone anchored hearing aids. METHODS Review and analysis of two studies from our own group, each comparing a speech processor with basic digital signal processing (either Baha Divino or Baha Intenso) and a processor with complex digital signal processing (either Baha BP100 or Baha BP110 power). The main differences between basic and complex signal processing are the number of audiologist accessible frequency channels and the availability and complexity of the directional multi-microphone noise reduction and loudness compression systems. RESULTS Both studies show a small, statistically non-significant improvement of speech understanding in quiet with the complex digital signal processing. The average improvement for speech in noise is +0.9 dB, if speech and noise are emitted both from the front of the listener. If noise is emitted from the rear and speech from the front of the listener, the advantage of the devices with complex digital signal processing as opposed to those with basic signal processing increases, on average, to +3.2 dB (range +2.3 … +5.1 dB, p ≤ 0.0032). DISCUSSION Complex digital signal processing does indeed improve speech understanding, especially in noise coming from the rear. This finding has been supported by another study, which has been published recently by a different research group. CONCLUSIONS When compared to basic digital signal processing, complex digital signal processing can increase speech understanding of users of bone anchored hearing aids. The benefit is most significant for speech understanding in noise.