Objetivos: Caracterizar o perfil audiológico dos indivíduos com malformações congênitas de orelha externa e/ou orelha média, na Divisão de Saúde Auditiva (DSA), do Hospital de Reabilitação de Anomalias Craniofaciais (HRAC), da Universidade de São Paulo (USP), campus Bauru e avaliar o benefício e a satisfação dos usuários de aparelhos de amplificação sonora individuais por condução óssea (AASI VO) retroauriculares. Modelo: Análise de prontuários, avaliação do benefício pelo teste de reconhecimento de sentenças com ruído competitivo e pelas medidas do ganho funcional e avaliação da satisfação pelo questionário internacional QI - AASI. Local: DSA, HRAC/USP, Bauru. Participantes: Foram analisados os prontuários de 170 indivíduos e, destes, selecionados 13, com malformações congênitas bilaterais de orelha externa e/ou orelha média, deficiência auditiva condutiva ou mista moderada ou severa e usuários de AASI VO retroauricular. Resultados: O perfil audiológico (n = 170) caracterizou-se pelo predomínio das malformações bilaterais (53%), das malformações no sexo masculino (61%), da deficiência auditiva condutiva moderada ou severa (80%) e da adaptação de AASI VO (56%). A orelha direita foi mais afetada (32%), quando consideradas apenas as malformações unilaterais. Na amostra selecionada (n = 13), o benefício foi comprovado pelo melhor desempenho obtido na avaliação proposta, na condição com AASI, quando comparada à condição sem AASI. A satisfação foi confirmada pelos escores elevados obtidos no QI-AASI. Conclusões: O uso do AASI VO retroauricular trouxe benefícios para o reconhecimento da fala no ruído e para a percepção do sinal acústico, além de satisfação aos indivíduos com malformações congênitas de orelha, portanto, esses dispositivos devem ser considerados como uma opção no tratamento dessa população. / Objectives: To characterize the audiological profile of the individuals with congenital malformations of the external and/or middle ear, in the Divisão de Saúde Auditiva (DSA) of the Hospital de Reabilitação de Anomalias Craniofaciais (HRAC) of Universidade de São Paulo (USP), in Bauru and to evaluate the benefits and satisfaction of patients fitted with bone conduction hearing aid (BCHA). Model: Analysis of files, evaluation of benefits by means of test of recognition of sentences with competitive noise and by the measures of the functional gain, and evaluation of satisfaction by International Outcome Inventory for Hearing Aids (IOI/HA). Participants: 170 patients? files were analyzed, from which 13 were selected with bilateral congenital malformations of the external and/or middle ear, moderate or severe conductive or mixed hearing loss, and patients fitted with BCHA. Results: The audiological profile (n=170) was characterized by the prevalence of bilateral malformations (53%), of malformations in males (61%), of the moderate or severe conductive hearing loss (80%) and of the fitting of BCHA (56%). The right ear was more affected (32%) when considered the unilateral malformations only. In the selected sample (n=13), the benefit was demonstrated by the best performance obtained in the proposed evaluation, in the condition with hearing aid, when compared to the condition without hearing aid. The satisfaction was confirmed by the high scores obtained in the IOI - HA. Conclusions: Fitting BCHA denoted improvement at speech perception in noise and sound detection. Individuals with congenital malformations of the ear were satisfied with this device, so that must be considered as an option to the treatment of this population.

Objetivos: Caracterizar o perfil audiológico dos indivíduos com malformações congênitas de orelha externa e/ou orelha média, na Divisão de Saúde Auditiva (DSA), do Hospital de Reabilitação de Anomalias Craniofaciais (HRAC), da Universidade de São Paulo (USP), campus Bauru e avaliar o benefício e a satisfação dos usuários de aparelhos de amplificação sonora individuais por condução óssea (AASI VO) retroauriculares. Modelo: Análise de prontuários, avaliação do benefício pelo teste de reconhecimento de sentenças com ruído competitivo e pelas medidas do ganho funcional e avaliação da satisfação pelo questionário internacional QI - AASI. Local: DSA, HRAC/USP, Bauru. Participantes: Foram analisados os prontuários de 170 indivíduos e, destes, selecionados 13, com malformações congênitas bilaterais de orelha externa e/ou orelha média, deficiência auditiva condutiva ou mista moderada ou severa e usuários de AASI VO retroauricular. Resultados: O perfil audiológico (n = 170) caracterizou-se pelo predomínio das malformações bilaterais (53%), das malformações no sexo masculino (61%), da deficiência auditiva condutiva moderada ou severa (80%) e da adaptação de AASI VO (56%). A orelha direita foi mais afetada (32%), quando consideradas apenas as malformações unilaterais. Na amostra selecionada (n = 13), o benefício foi comprovado pelo melhor desempenho obtido na avaliação proposta, na condição com AASI, quando comparada à condição sem AASI. A satisfação foi confirmada pelos escores elevados obtidos no QI-AASI. Conclusões: O uso do AASI VO retroauricular trouxe benefícios para o reconhecimento da fala no ruído e para a percepção do sinal acústico, além de satisfação aos indivíduos com malformações congênitas de orelha, portanto, esses dispositivos devem ser considerados como uma opção no tratamento dessa população. / Objectives: To characterize the audiological profile of the individuals with congenital malformations of the external and/or middle ear, in the Divisão de Saúde Auditiva (DSA) of the Hospital de Reabilitação de Anomalias Craniofaciais (HRAC) of Universidade de São Paulo (USP), in Bauru and to evaluate the benefits and satisfaction of patients fitted with bone conduction hearing aid (BCHA). Model: Analysis of files, evaluation of benefits by means of test of recognition of sentences with competitive noise and by the measures of the functional gain, and evaluation of satisfaction by International Outcome Inventory for Hearing Aids (IOI/HA). Participants: 170 patients? files were analyzed, from which 13 were selected with bilateral congenital malformations of the external and/or middle ear, moderate or severe conductive or mixed hearing loss, and patients fitted with BCHA. Results: The audiological profile (n=170) was characterized by the prevalence of bilateral malformations (53%), of malformations in males (61%), of the moderate or severe conductive hearing loss (80%) and of the fitting of BCHA (56%). The right ear was more affected (32%) when considered the unilateral malformations only. In the selected sample (n=13), the benefit was demonstrated by the best performance obtained in the proposed evaluation, in the condition with hearing aid, when compared to the condition without hearing aid. The satisfaction was confirmed by the high scores obtained in the IOI - HA. Conclusions: Fitting BCHA denoted improvement at speech perception in noise and sound detection. Individuals with congenital malformations of the ear were satisfied with this device, so that must be considered as an option to the treatment of this population.

The work and results presented in this dissertation concern two complimentary studies that are rooted in surface acoustic waves and transducer study. Surface acoustic wave devices are utilized in a variety of fields that span biomedical applications to radio wave transmitters and receivers. Of interest in this dissertation is the study of surface acoustic wave interaction with polydimethylsiloxane. This material, commonly known as PDMS, is widely used in the microfluidic field applications in order to create channels for fluid flow on the surface of a piezoelectric substrate. The size, and type of PDMS that is created and ultimately etched on the surface of the substrate, plays a significant role in its operation, chiefly in the insertion loss levels experienced. Here, through finite element analysis, via ANSYS® 15 Finite Element Modeling software, the insertion loss levels of varying PDMS sidewall channel dimensions, from two to eight millimeters is investigated. The simulation is modeled after previously published experimental data, and the results demonstrate a clear increase in insertion loss levels with an increase in channel sidewall dimensions. Analysis of the results further show that due to the viscoelastic nature of PDMS, there is a non -linear increase of insertion loss as the sidewall dimensions thicken. There is a calculated variation of 8.31 decibels between the insertion loss created in a microfluidic device with a PDMS channel sidewall thickness of eight millimeters verse a thickness of two millimeters. Finally, examination of the results show that insertion loss levels in a device are optimized when the PDMS sidewall channels are between two and four millimeters. The second portion of this dissertation concerns the calibration of an ultrasonic transducer. This work is inspired by the need to properly quantify the signal generated by an ultrasonic transducer, placed under a static loading condition, that will be used in measuring ultrasonic bone conducted frequency perception of human subjects. Ultrasonic perception, classified as perception beyond the typical hearing limit of approximately 20 kHz, is a subject of great interest in audiology. Among other reasons, ultrasonic signal perception in humans is of interest because the mechanism by which either the brain or the ear interprets these signals is not entirely understood. Previous studies have utilized ultrasonic transducers in order to study this ultrasonic perception; however, the calibration methods taken, were either incomplete or did not properly account for the operation conditions of the transducers. A novel transducer calibration method is detailed in this dissertation that resolves this issue and provides a reliable means by which the signal that is being created can be compared to the perception of human subjects.

Der knochenleitende Hörverlust, der auf eine mögliche Schädigung des Hörorgans durch die Operation hinweist, ist eine unerwünschte postoperative Komplikation in der Hals-Nasen-Ohren-Heilkunde. Lärm, der durch das Bohren verursacht wird, könnte die Hauptursache für diese Komplikation sein. Um diese Hypothese zu überprüfen, ist der erste Schritt die Quantifizierung dieses Lärms. In den meisten früheren Studien wurde ein Schallpegelmesser als quantitatives Werkzeug verwendet, das jedoch nur die Messung von Luftschall ermöglicht und durch den Abstand zur Schallquelle beeinflusst wird. Neben Luftschall scheint der Knochenschall während der Ohroperation intuitiv wahrscheinlicher zu iatrogenener Hörverlust zu führen. Die Schwierigkeit bei der Messung von Knochenschall besteht darin, dass es kein Standardinstrument wie einen Schallpegelmesser gibt, das den Geräuschwert direkt messen kann. In früheren begrenzten Untersuchungen des Knochenschalls wurde ein Kompromissweg eingeschlagen, bei dem eine Korrelation zwischen dem knochenleitenden Schalldruck bei einer bestimmten Frequenz und der Beschleunigung um das Ohr herum hergestellt wurde. Ersteres wurde durch den Knochenwandler des Audiometers ausgeübt, während letzteres durch den Beschleunigungssensor protokolliert wurde. Durch die Messung der Beschleunigung ist es somit möglich, indirekt auf den knochenleitenden Schallpegel zu schließen. In Übereinstimmung mit diesem Gedanken hat unser Forschungsteam in einer früheren Studie ein Messsystem für knochenleitenden Lärm entwickelt, das aus einem Beschleunigungssensor, einem Piezovibrator und einem Kraftsensor besteht, wobei die Kombination der beiden letzten Komponenten als gleichwertig zum Knochenwandler des Audiometers betrachtet werden kann. Mit diesem Gerät können wir im Vergleich zu einem Audiometer diese entsprechende Beziehung über einen größeren Frequenzbereich hinweg abtasten und die Überlagerung von Schalldruckpegeln mit unterschiedlichen Phasen bei jeder Frequenz berechnen. In dieser Studie wurde die Beziehungskurve (FRF) zwischen Kraft und Beschleunigung weiter optimiert, um den Einfluss abnormal hoher Werte zu reduzieren. Darüber hinaus wurde ein Kalibrierungskoeffizient, der aus einer Gruppe von Experimenten an Felsenbeinen gewonnen wurde, eingeführt, um den knochenleitenden Lärm beim Bohren am runden Fensternische genauer widerzuspiegeln. Alle diese Verbesserungen wurden angewendet, um den durch das Bohren verursachten knochenleitenden Lärm bei einer Serie von 25 Cochlea-Implantationsverfahren zu quantifizieren, was bisher die umfangreichste Studiengruppe in diesem Bereich darstellt. Gemäß den Messergebnissen wurden die maximalen Schalldruckpegel mit A-Bewertung und schneller Zeitbewertung (LAF) zwischen 111 dB und 122 dB aufgezeichnet. LAF trat am häufigsten bei etwa 95 dB auf. Die tägliche Lärmdosis, die die Gesamtmenge des Lärms in der Operation widerspiegelt, variierte zwischen 15,8% und 494,8% mit einem Durchschnitt von 138,4%. Trotz der Hinzufügung des Korrekturwerts, der aus dem Felsenbeinexperiment erhalten wurde, wies die Vorbereitung des Implantatbett immer noch die höchste Lärmdosis und Lärmintensität (Dosis/Zeit) unter den 4 geteilten Bohrschritten auf: Implantatbett, Mastoidektomie, Tympanotomie und Cochleotomie (Bohren am Rundfensternische). Basierend auf den obigen Daten und gemäß den Lärmschutzstandards des NIOSH wird die Lärmbelastung durch das Bohren während des CI-Verfahrens nicht als besonders gefährlich eingestuft, und solange der Bohrer die innere Membran nicht berührt, ist das Entfernen des runden Fensterfachs durch Bohren ein relativ sicherer Eingriff zur Erhaltung des Resthörens. Es ist erwähnenswert, dass alle Arten von Lärmschutzstandards auf Messungen mit einem Schallpegelmesser basieren, der den Schalldruck in der Luft direkt misst. Jedoch, in der Branche der Knochenleitungsvorrichtungen, z.B. Knochenleitungskopfhörer, entspricht der Parameter, der in diesem Kontext den Schalldruck darstellt, der vom Wandler ausgeübten Kraft. Angesichts der Tatsache, dass es an Forschungen und Schutzstandards bezüglich der Schäden fehlt, die Überlastkräfte unserem Gehör zufügen können, wird in dieser Studie die ISO 389-3 Norm im Bezug auf Audiometer verwendet, um die Kraft indirekt in den Schallpegel umzurechnen. Daher werden alle Schalldruckwerte aus den Kraftwerten abgeleitet. Gleichzeitig werden alle Kraftwerte aus den Beschleunigungswerten durch die etablierte Frequenzgangfunktion abgeleitet. In Zukunft würden Bemühungen, die Anzahl der Schritte in diesem Umwandlungsprozess zu reduzieren oder die Umwandlungspräzision zu verbessern, dazu beitragen, die Genauigkeit der Messungen von knochenleitendem Lärm zu erhöhen. Es wird auch erwartet, eine Korrelationsstudie zwischen dem protokollierten Lärmpegel und dem postoperativen knochenleitenden Hörpegel bei Patienten durchzuführen, die über praktisches Hörvermögen verfügen.:1. Introduction 2. Theoretical Basis 2.1. Sound Energy 2.2. Fourier transform of signals and parameter settings 2.2.1. Conversion between time-domain signals and frequency-domain signals 2.2.2. Transform velocity to acceleration or displacement in frequency domain 2.3. Frequency response function 2.4. Reflection and Transmission of sound wave 2.5. Loudness simulation: ISO 389-3:2016 and A-weighting 2.6. Sound level meter: Fast, Slow and Impulse time weighting 3. Method 3.1. Overall road map 3.2. Calibration 3.2.1. General layout 3.2.2. Signal configuration and parameters 3.2.3. Optimization of calibration curve 3.3. Acquisition of correction coefficient by temporal bone experiment. 3.3.1. General 3.3.2. Anatomy approach and equipment layout 3.3.3. Signal configuration and parameters 3.4. Loudness stimulation, Sound level meter stimulation and Noise value evaluation 3.5. Measurements in the cochlear implantation operation 3.5.1. Patients 3.5.2. Cochlear Implantation 3.5.3. Burrs 4. Results 4.1. Correction of LAF derived from cochleotomy 4.2. General condition 4.3. Maximum LAF 4.4. Time distribution of LAF above 85dB. 4.5. Drilling-induced noise production by different surgeons 4.6. Noise comparison between different drilling location 4.7. Noise comparison between different burrs 5. Discussion 5.1. Error analysis 5.1.1. The error from calibration 5.1.2. The error from correction coefficient 5.1.3. The error from ISO389-3 and A-weighting 5.1.4. The error from the standard of NIOSH 5.2. In comparison with other bone-conducted noise measurements 5.2.1. Method comparison 5.2.2. Results comparison 5.2.3. In comparison with air-conducted noise measurements 5.2.4. Can this level of noise exposure cause hearing impairment? 5.2.5. Drilling at the round window niche 5.2.6. Factors affecting drilling-induced noise 6. Summary/Zusammenfassung References Supplementary calculation code for this project Acknowledgments Anlage 1: Erklärungen zur Eröffnung des Promotionsverfahrens Anlage 2: Bestätigung über Einhaltung der aktuellen gesetzlichen Vorgaben / Bone conductive hearing decline which implies possible damage to the hearing organ caused by the surgery, is an undesirable postoperative complication in otolaryngology. Drilling-induced noise may be the primary cause of this complication. To verify this hypothesis, the first step is to quantify this noise. Sound level meter has been used as a quantitative tool in the majority of past studies, which only allows for the measurement of airborne noise and is influenced by the distance from the sound source. In addition to airborne noise, intuitively, bone conduction noise during the ear surgery appears to be more likely to cause iatrogenic hearing loss. The difficulty of bone conduction noise measurement is that there is no standard instrument like a sound level meter that can directly measure the noise value. In prior limited investigations of bone conduction noise, a compromised way was employed, which involved establishing a correlation between bone-conducted sound pressure at the specific frequency and acceleration around the ear. The former was exerted by the bone transducer of the audiometer, while the latter was logged by the accelerometer. Thus, by measuring the acceleration, it is possible to indirectly infer the bone-conducted sound level. Following the same train of thought, our research team developed a measurement system for bone-conducted noise in previous study which consisted of an accelerometer, a piezoshaker and a force sensor, the combination of latter two can be regarded as equivalent to the bone transducer of audiometer. Through this device, compared to an audiometer, we can sample this corresponding relationship across a wider range of frequencies and calculate the superposition of sound levels with different phase at each frequency. In this study, the relationship curve (FRF) between force and acceleration has been further optimized to reduce the influence of abnormally high values. Additionally, a calibration coefficient obtained from a group of temporal bone experiments has been introduced to more accurately reflect bone-conducted noise when drilling at the round window niche. All of those enhancements were applied to quantify the drilling-induced bone conduction noise in a batch of 25 cochlear implantation procedures, which constitutes the most extensive study cohort in this field thus far. According to the measurement results, the maximum values of sound pressure level with A-weighting and Fast-time-weighting (LAF) were recorded between 111dB to 122dB. LAF most frequently occurred around 95 dB. Daily noise dose reflecting the total amount of noise in the surgery varied from 15.8% to 494.8% with a mean of 138.4%. Despite the addition of correction value which obtained from temporal bone experiment, the implant bed preparation still had the highest noise dose and noise density (dose/time) among 4 divided drilling steps: implant bed, mastoidectomy, typampotomy and cochleotomy (drilling at the round window niche). Based on the above data and according to the NIOSH noise protection standards, the noise exposure caused by drilling during CI procedure is not deemed highly hazardous and as long as the burr does not touch the inner membrane, removing the round window niche by drilling is a relatively safe procedure for preserving residual hearing. It is worth noting that all kinds of noise protection standards are based on measurements with sound level meter which directly gauges the sound pressure in the air. However, in the industry of bone conduction device, e.g., bone conduction headphone, the parameter corresponding to sound pressure in this context is the force exerted by transducer. Given the fact that lack the researches and protection standards regarding the damage that overload force can cause to our hearing, ISO 389-3 standard in terms of audiometer is employed to indirectly convert the force to the sound level in this study. Hence, all sound pressure values are inferred from force values. Meanwhile, all force values are deduced from acceleration values by the established frequency response function. In the future, any efforts aimed at reducing the number of steps involved in this conversion process or improving conversion precision would help enhance the accuracy of bone conduction noise measurements. It is also expected to carry out the correlation study between the logged noise level and post-operative bone conduction hearing level in the patients who has practical hearing.:1. Introduction 2. Theoretical Basis 2.1. Sound Energy 2.2. Fourier transform of signals and parameter settings 2.2.1. Conversion between time-domain signals and frequency-domain signals 2.2.2. Transform velocity to acceleration or displacement in frequency domain 2.3. Frequency response function 2.4. Reflection and Transmission of sound wave 2.5. Loudness simulation: ISO 389-3:2016 and A-weighting 2.6. Sound level meter: Fast, Slow and Impulse time weighting 3. Method 3.1. Overall road map 3.2. Calibration 3.2.1. General layout 3.2.2. Signal configuration and parameters 3.2.3. Optimization of calibration curve 3.3. Acquisition of correction coefficient by temporal bone experiment. 3.3.1. General 3.3.2. Anatomy approach and equipment layout 3.3.3. Signal configuration and parameters 3.4. Loudness stimulation, Sound level meter stimulation and Noise value evaluation 3.5. Measurements in the cochlear implantation operation 3.5.1. Patients 3.5.2. Cochlear Implantation 3.5.3. Burrs 4. Results 4.1. Correction of LAF derived from cochleotomy 4.2. General condition 4.3. Maximum LAF 4.4. Time distribution of LAF above 85dB. 4.5. Drilling-induced noise production by different surgeons 4.6. Noise comparison between different drilling location 4.7. Noise comparison between different burrs 5. Discussion 5.1. Error analysis 5.1.1. The error from calibration 5.1.2. The error from correction coefficient 5.1.3. The error from ISO389-3 and A-weighting 5.1.4. The error from the standard of NIOSH 5.2. In comparison with other bone-conducted noise measurements 5.2.1. Method comparison 5.2.2. Results comparison 5.2.3. In comparison with air-conducted noise measurements 5.2.4. Can this level of noise exposure cause hearing impairment? 5.2.5. Drilling at the round window niche 5.2.6. Factors affecting drilling-induced noise 6. Summary/Zusammenfassung References Supplementary calculation code for this project Acknowledgments Anlage 1: Erklärungen zur Eröffnung des Promotionsverfahrens Anlage 2: Bestätigung über Einhaltung der aktuellen gesetzlichen Vorgaben

Made available in DSpace on 2016-04-27T18:12:34Z (GMT). No. of bitstreams: 1 Tatiana Fernandes Cili.pdf: 1959713 bytes, checksum: 95c16fc57e6e2cf785b81f8534de86bf (MD5) Previous issue date: 2008-05-14 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Clinical audiology literature and practice raise questions about bone conduction assessment results. The most common questions are related to the reliability of bone conduction thresholds as they suffer a lot of artifacts that may mislead the results obtained. Silman & Silverman (1997) describe two important factors that could interfere in such measurement: acoustic radiation (escaping acoustic energy that can be heard by air conduction, mainly in the high frequencies) and bone vibrator positioning in the mastoid. In order to obtain bone conduction thresholds in 2 kHz, or at higher frequencies, researchers suggest the insertion of earplugs in either the tested ear or in both ears to prevent acoustic radiation. In order to increase reliability on bone conduction evaluation researchers suggest that the patient must position the bone vibrator at the point on mastoid that he has the biggest sensation of sound stimuli. Objectives: 1. to investigate the bone vibrator s positioning influence in bone conduction thresholds evaluation for 500, 1k, 2k, 3k, and 4 kHz in normal hearing subjects. 2. to investigate the influence of insert earplugs on bone conduction thresholds measurement for 2000, 3000 and 4000 Hz in normal hearing subjects. Specific Objectives: 1- to determine the bone conduction sensitivity due to the influence of the bone vibrator s positioning in the mastoid to obtain bone conduction thresholds at 500, 1k, 2k, 3k, and 4 kHz in normal hearing subjects. 2 - to determine bone conduction threshold with and without insert earplug in order to investigate the presence of the acoustic radiation phenomenon during the bone conduction assessment at 2k, 3k, and 4 kHz in normal hearing subjects. Methods: Thirty six ears from 18 subjects were examined. Both ears were tested for air and bone conduction in a sound booth. The RADIOEAR B71 bone vibrator was used to assess bone conduction at 500, 1k, 2k, 3k, and 4 kHz. Two audiometers were used: Interacoustics AC40 and Betamedical Beta 6000. To evaluate the effect of the bone vibrator positioning, bone conduction thresholds were obtained using narrow band noise, at the opposite ear, at 30 dB HL in 1 dB steps (Ritcher; Brinkman; 1981); and to assess the effects of the acoustic radiation the examiner positioned the bone vibrator and inserted a foam earplug in the tested ear (Robinson; Shipton; 1982). Results: Bone vibrator s positioning influence was present in bone conduction thresholds evaluation at 500, 1000 e 3000 Hz, in more than 20% of the cases. This study proved that, when assessing bone conduction, the acoustic radiation phenomenon was present at 2k, 3k, and 4 kHz in 70% of the cases, mainly at 3 kHz. Conclusion: The acoustic radiation phenomenon was present mainly at 3 kHz, besides being present at 2k and 4 kHz. This could lead to an inaccurate interpretation of test results, which depend on reliable air and bone conduction values / A literatura e a prática na área da audiologia clínica, nos fazem questionar até que ponto o resultado da avaliação da via óssea de um sujeito é verdadeira ou é produto da interferência de atos ou fatos que ocorrem durante a audiometria. Silman e Silverman (1997) pontuam dois importantes fatores que podem interferir nessa medida: a radiação acústica (fuga de energia sonora do vibrador ósseo que poderia ser ouvida pela via aérea, principalmente em freqüências altas) e o posicionamento do vibrador ósseo na mastóide. Para obtenção dos limiares por via óssea em 2 kHz ou em freqüências mais altas, autores sugerem a inserção de plugs na orelha sob teste ou nas duas orelhas, para prevenir a radiação acústica. Para evitar o efeito do posicionamento do vibrador ósseo, os autores sugerem que o paciente posicione o vibrador ósseo no local onde sente o estímulo acústico mais intenso. Objetivos: 1. investigar a influência do posicionamento do vibrador ósseo na mastóide na obtenção do limiar tonal por via óssea para as freqüências de 500, 1k, 2k, 3k e 4k Hz, em sujeitos sem queixa auditiva; 2. investigar a influência do plug auricular na medida dos limiares ósseos de 2000, 3000 e 4000 Hz. Objetivos específicos: 1 - determinar os valores de sensibilidade da via óssea devido à influência do posicionamento do vibrador ósseo na mastóide para a obtenção do limiar tonal por via óssea para as freqüências de 500, 1k, 2k, 3k e 4k Hz, em sujeitos sem queixa auditiva. 2 - determinar os valores de sensibilidade da via óssea com e sem e com plug auditivo, para as freqüências de 2k, 3k e 4k Hz, em sujeitos sem queixa auditiva, para determinar a existência do fenômeno da radiação acústica na obtenção do limiar tonal por via óssea. Método: Foram examinadas 36 orelhas de 18 indivíduos; audiometria tonal por via aérea e óssea em ambas as orelhas, em cabine acústica. O modelo do vibrador ósseo foi RADIOEAR B71 para avaliar as freqüências 500, 1k, 2k, 3k, 4k Hz (via óssea). Audiômetro da Marca Interacoustics, modelo AC40 e da Marca Betamedical, modelo Beta 6000. Para avaliar o efeito do posicionamento do vibrador ósseo foi realizada a pesquisa do limiar de sensibilidade auditiva da via óssea, em degraus de 1 dB, com ruído de banda estreita de 30 dBNA, na orelha oposta (Richter; Brinkmann; 1981); para avaliar o efeito da radiação acústica foi realizada a medida da via óssea, com o vibrador ósseo posicionado pelo examinador e inserção de um plug automoldável na orelha examinada, (Robinson; Shipton; 1982). Resultados: Em 500, 1 e 3 kHz mais de 20% das pessoas tiveram seus limiares por via óssea alterados em mais de 6 dB, devido ao efeito do posicionamento do vibrador ósseo. Este estudo comprovou o fenômeno da radiação acústica nas freqüências de 2, 3 e 4 kHz quando a via óssea foi avaliada, principalmente em 3 kHz, em 70% dos casos. Conclusão: O fenômeno da radiação acústica estava presente principalmente em 3 kHz, além de estar presente em 2 e 4 kHz. O que pode levar a interpretação errônea dos resultados audiométricos que dependem da exatidão dos valores aéreos e ósseos

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Bone conduction transmission and head‐shadow effects were determined with transcranial completely‐in‐the‐canal (TCCIC) CROS hearing aids. Five subjects with documented profound unilateral hearing loss and experience with traditional CROS/BICROS fittings (TCROS) were tested with a CIC hearing aid placed in their poorer ear. Peak SPL was measured at the tympanic membrane and ranged from 105–115 dB SPL at 2000 Hz. Pure‐tone crossover thresholds and functional gain tested at frequencies from 250–8000 Hz varied considerably more than the SPL measures. The pure‐tone results indicated that sensitivity in the better ear was moderately associated with functional gain across frequency. Speech recognition was then tested in the sound field in two conditions: direct (noise in the poorer ear, speech in the better ear) and indirect (noise in the better ear, speech in the poorer ear) at S/Ns of −6, 0, +6, +12, and quiet. The TCCIC fittings were more effective than TCROS aids across S/Ns, particularly in the direct condition. In the indirect condition, the two fittings performed similarly. When data were pooled across conditions, the TCCIC aids provided better word recognition than the TCROS aids, particularly for those subjects with greater sensitivity in the better ear.

No description available.