Voltage readout from a piezoelectric intracochlear acoustic transducer implanted in a living guinea pig.

The ability to measure the voltage readout from a sensor implanted inside the living cochlea enables continuous monitoring of intracochlear acoustic pressure locally, which could improve cochlear implants. We developed a piezoelectric intracochlear acoustic transducer (PIAT) designed to sense the acoustic pressure while fully implanted inside a living guinea pig cochlea. The PIAT, fabricated using micro-electro-mechanical systems (MEMS) techniques, consisted of an array of four piezoelectric cantilevers with varying lengths to enhance sensitivity across a wide frequency bandwidth. Prior to implantation, benchtop tests were conducted to characterize the device performance in air and in water. When implanted in the cochlea of an anesthetized guinea pig, the in vivo voltage response from the PIAT was measured in response to 80-95 dB sound pressure level 1-14 kHz sinusoidal acoustic excitation at the entrance of the guinea pig's ear canal. All sensed signals were above the noise floor and unaffected by crosstalk from the cochlear microphonic or external electrical interference. These results demonstrate that external acoustic stimulus can be sensed via the piezoelectric voltage response of the implanted MEMS transducer inside the living cochlea, providing key steps towards developing intracochlear acoustic sensors to replace external or subcutaneous microphones for auditory prosthetics.

[Human ear finite element model study of the effects of ear canal and middle ear cavity on air conduction and bone conduction].

Objective:To study the influence of the ear canal and middle ear cavity on air conduction and bone conduction. Method:A finite element model of the human middle ear was established. By establishing the external ear canal and the middle ear cavity, we evaluated the effects of the external canal and the middle ear cavity on air conduction and bone conduction. Result:In air conduction, the external canal improved the stapes response at the frequency range of 0.5 kHz to 6 kHz, and the maximum increase was 11 dB at 3 kHz. The middle ear cavity mainly reduced the response of stapes at mid-low frequency, with the drops of 2-4 dB under 2 kHz; in bone conduction, ear canal slightly reduced the low-frequency response, but increased the response of the stapes at the mid-high frequency, with a maximum increase of 1.9 dB at 1.5 kHz. The middle ear cavity mainly increased the stapes response at mid-frequency near 1.5 kHz, with a maximum increase of 2.5 dB. Conclusion:Our results show that, in air conduction, the ear canal significantly increases the middle-frequency response, while the middle ear cavity decreases the low-mid frequency response. Whereas, the ear canal and the middle ear cavity have slightly effect on bone conduction.

Contralateral Occlusion Test (COT): the effect of external ear canal occlusion with aging / Teste de Oclusão Contralateral (TOC): o efeito da oclusão do canal auditivo externo com a idade

ABSTRACT Purpose This study aimed to evaluate the effects of complete external ear canal occlusion on hearing thresholds with aging. The goal was to decide which tuning fork is more appropriate to use for the contralateral occlusion test (COT), in individuals of different ages. Methods Forty-two normal hearing subjects between 21 and 67 years were divided into three age groups (20-30 years, 40-50 years, and 60-70 years). Participants underwent sound field audiometry tests with warble tones, with and without ear canal occlusion. Each ear was tested with the standard frequencies (250, 500, 1000, and 2000 Hz). The contralateral ear was suppressed by masking. Results Hearing thresholds showed an increase as the frequency increased from 20.85 dB (250 Hz, 20-30 years group) to 48 dB (2000 Hz, 60-70 years group). The threshold differences between occlusion and no occlusion conditions were statistically significant and increased ranging from 11.1 dB (250 Hz, 20-30 years group) to 32 dB (2000 Hz, 20-30 years group). We found statistically significant differences for the three age groups and for all evaluations except to 500 Hz difference and average difference. The mean hearing loss produced by occlusion at 500 Hz was approximately 19 dB. We found no statistically significant differences between right and left ears and gender for all measurements. Conclusion We conclude that the use of the 512 Hz tuning fork is the most suitable for COT, and its use may allow clinicians to distinguish mild from moderate unilateral conductive hearing loss.

RESUMO Objetivo O objetivo deste estudo foi avaliar o efeito da oclusão completa do canal auditivo externo nos limiares auditivos, em indivíduos de idades distintas, para apurar qual o diapasão mais adequado na realização do teste de oclusão contralateral (TOC). Método 42 indivíduos normo-ouvintes (21-67 anos) foram divididos em três grupos etários (20-30, 40-50 e 60-70 anos). Os participantes foram avaliados com testes de audiometria tonal liminar em campo livre, com e sem oclusão completa do canal auditivo externo. Cada ouvido foi testado para as frequências 250, 500, 1000 e 2000 Hz. No ouvido contralateral, foi realizado mascaramento, para evitar a ocorrência de audição contralateral. Resultados Verificou-se aumento dos limiares auditivos, diretamente proporcional ao aumento da frequência (desde 20.85 até 48 dB). A diferença nos limiares auditivos entre a condição de oclusão e de não oclusão foi estatisticamente significativa em todas as frequências e aumentou de forma diretamente proporcional com a frequência (desde 11.1 até 32 dB). Foram também encontradas diferenças estatisticamente significativas para os três grupos etários, em todos os parâmetros, exceto na diferença a 500 Hz e na diferença total média. A perda auditiva média resultante da oclusão aos 500 Hz foi de 19 dB. Não se encontraram diferenças estatisticamente significativas entre o ouvido direito e o esquerdo, e entre o gênero. Conclusão A utilização do diapasão de 512 Hz é a mais adequada para o TOC. A sua utilização pode permitir aos clínicos, em ambiente de consulta e de forma rápida, a distinção entre perda condutiva de grau leve a moderada.

Including auditory tube function on models is relevant to assess water exposure after tympanostomy tubes-Multiphase computerized fluid dynamics model.

INTRODUCTION: Myringotomy with tympanostomy tube is the most common otologic surgery and some patients are still advised to avoid water. However, there is no evidence supporting this, with published papers questioning the need for this advice. METHODS: A Multiphase Computational Fluid Dynamics (CFD) model was created using computerized tomography images of a child's healthy ear. It was then used to study the flow of fluids through the external ear, tympanic cavity, and auditory tube, with and without submersion. RESULTS: The model accurately described the behavior of the air retained in the patient's nasopharynx and tympanic cavity. A simulated elevation of pressure in the external auditory canal without submersion, without increase of pressure in the nasopharynx, demonstrated that fluids promptly crossed the tympanostomy tube into the middle ear. However, simulated elevation of pressure in the external auditory canal with concurrent elevation of air pressure in the nasopharynx during submersion did not lead to passive tube opening nor to any detectable flow through the tympanostomy tube. CONCLUSIONS: In the model, submersion increases pressure in the nasopharynx which offsets the pressure in the external auditory canal. So, in the absence of a pressure gradient, no passive tubal opening took place, and no air or fluid flow was detected through the transtympanic tube. This model now includes the exhaust function of the auditory tube in the model and shows its relevance.

[The topographical and anatomical characteristic of the anterior part of the external auditory passage and the tympanic cavity]. / Topografoanatomicheskaia kharakteristika perednego otdela naruzhnogo slukhovogo prokhoda i barabannoi polosti.

The objective of the present work was to overview the currently available literature data on microtopographic anatomy of the anterior portion of the middle ear and the external auditory passage. Manipulations on these structures during miringoplasty surgery appear to be the most difficult and laborious operations because this space is anatomically very narrow and curved; moreover, it contains the important intimate structures of the middle ear and is located very close to the temporomandibular joint. The knowledge of microsurgical anatomy of the anterior part of the middle ear and the external auditory passage is paramount in the context of the improvement of the professional skills of the surgeons. The current literature data provide a basis for the conclusion that many aspects of microsurgical anatomy of the anterior part of the tympanic cavity and the external auditory passage thus far remain poorly explored. This assertion is especially true as regards the relief of the mucous membrane overlying these structure and their supply with arterial blood. Further clarification of these aspects is needed.

Aural exostoses (surfer's ear) provide vital fossil evidence of an aquatic phase in Man's early evolution.

For over a century, otolaryngologists have recognised the condition of aural exostoses, but their significance and aetiology remains obscure, although they tend to be associated with frequent swimming and cold water immersion of the auditory canal. The fact that this condition is usually bilateral is predictable since both ears are immersed in water. However, why do exostoses only grow in swimmers and why do they grow in the deep bony meatus at two or three constant sites? Furthermore, from an evolutionary point of view, what is or was the purpose and function of these rather incongruous protrusions? In recent decades, paleoanthropological evidence has challenged ideas about early hominid evolution. In 1992 the senior author suggested that aural exostoses were evolved in early hominid Man for protection of the delicate tympanic membrane during swimming and diving by narrowing the ear canal in a similar fashion to other semiaquatic species. We now provide evidence for this theory and propose an aetiological explanation for the formation of exostoses.

Novel classification of the posterior auricular artery based on angiographical appearance.

PURPOSE: To investigate the length variation of the posterior auricular artery and propose a novel classification of the posterior auricular artery based on angiographical appearance. PATIENTS AND METHODS: A series of 234 consecutive patients who had undergone conventional cerebral angiography was analyzed. The posterior auricular artery was examined on the lateral projection of the external carotid or common carotid arteriography. The posterior auricular artery was classified into four groups by length, using the external auditory canal and the top of the helix as radiographical landmarks. Our proposed classification is as follows: Type A, posterior auricular artery terminates between its origin and the center of the external auditory canal; Type B, posterior auricular artery terminates between the center of the external auditory canal and the top of the helix; Type C, posterior auricular artery terminates between the top of the helix and the vertex; and Type D, posterior auricular artery reaches up to the vertex. RESULTS: A total of 424 (right, 214; left, 210) posterior auricular arteries were analyzed in 111 men and 123 women aged 11 to 91 years (mean, 61.0 years) examined for aneurysms in 78 cases, occlusive vascular diseases in 56, intracranial hemorrhages in 41, tumors in 35, and others in 24. Types A, B, C, and D were found in 15.1%, 34.9%, 48.8%, and 1.2% of the patients, respectively. CONCLUSION: A novel classification of the posterior auricular artery identifies four types based on its length on cerebral angiography.

Retrosigmoid removal of small acoustic neuroma: curative tumor removal with preservation of function.

OBJECT: Management of small acoustic neuromas (ANs) consists of 3 options: observation with imaging follow-up, radiosurgery, and/or tumor removal. The authors report the long-term outcomes and preservation of function after retrosigmoid tumor removal in 44 patients and clarify the management paradigm for small ANs. METHODS: A total of 44 consecutively enrolled patients with small ANs and preserved hearing underwent retrosigmoid tumor removal in an attempt to preserve hearing and facial function by use of intraoperative auditory monitoring of auditory brainstem responses (ABRs) and cochlear nerve compound action potentials (CNAPs). All patients were younger than 70 years of age, had a small AN (purely intracanalicular/cerebellopontine angle tumor ≤ 15 mm), and had serviceable hearing preoperatively. According to the guidelines of the Committee on Hearing and Equilibrium of the American Academy of Otolaryngology-Head and Neck Surgery Foundation, preoperative hearing levels of the 44 patients were as follows: Class A, 19 patients; Class B, 17; and Class C, 8. The surgical technique for curative tumor removal with preservation of hearing and facial function included sharp dissection and debulking of the tumor, reconstruction of the internal auditory canal, and wide removal of internal auditory canal dura. RESULTS: For all patients, tumors were totally removed without incidence of facial palsy, death, or other complications. Total tumor removal was confirmed by the first postoperative Gd-enhanced MRI performed 12 months after surgery. Postoperative hearing levels were Class A, 5 patients; Class B, 21; Class C, 11; and Class D, 7. Postoperatively, serviceable (Class A, B, or C) and useful (Class A or B) levels of hearing were preserved for 84% and 72% of patients, respectively. Better preoperative hearing resulted in higher rates of postoperative hearing preservation (p = 0.01); preservation rates were 95% among patients with preoperative Class A hearing, 88% among Class B, and 50% among Class C. Reliable monitoring was more frequently provided by CNAPs than by ABRs (66% vs 32%, p < 0.01), and consistently reliable auditory monitoring was significantly associated with better rates of preservation of useful hearing. Long-term follow-up by MRI with Gd administration (81 ± 43 months [range 5-181 months]; median 7 years) showed no tumor recurrence, and although the preserved hearing declined minimally over the long-term postoperative follow-up period (from 39 ± 15 dB to 45 ± 11 dB in 5.1 ± 3.1 years), 80% of useful hearing and 100% of serviceable hearing remained at the same level. CONCLUSIONS: As a result of a surgical technique that involved sharp dissection and internal auditory canal reconstruction with intraoperative auditory monitoring, retrosigmoid removal of small ANs can lead to successful curative tumor removal without long-term recurrence and with excellent functional outcome. Thus, the authors suggest that tumor removal should be the first-line management strategy for younger patients with small ANs and preserved hearing.

Pressao sonora gerada por equipamentos sonoros portateis individuais / Sound pressure level generated by individual portable sound equipment

Introdução: O uso de equipamentos portáteis sonoros individuais pode ser um risco auditivo, pois o som é gerado diretamente no meato acústico externo. Acredita-se que fones diferentes proporcionam amplificações diferentes, pois causam variações de volume e de ressonância conforme suas inserções. Objetivos: Verificar a pressão sonora a que jovens estão expostos quando fazem uso de equipamentos sonoros portáteis individuais com dois diferentes fones: de inserção e de inserção anatômico. Materiais e métodos: Trata-se de uma pesquisa experimental. Para tanto, foram feitas medições em 54 orelhas de 27 jovens com idades entre 18 e 30 anos, com os dois tipos de fones. Também foram registrados picos de ressonância da orelha externa com e sem fone. Resultados: Observou-se que o fone de inserção anatômico apresenta aumento do nível de pressão sonora estatisticamente significante em comparação com o fone de inserção para todas as frequências avaliadas. Não há uma correlação entre o novo pico de ressonância do meato fechado e a frequência na qual se obteve os maiores níveis de pressão sonora com o fone. Observou-se diferença estatisticamente significativa entre orelhas para algumas frequências com os diferentes fones. Conclusão: O fone de inserção anatômico gera um maior nível de pressão sonora que o fone de inserção. .

Introduction: The use of Personal Digital Audio Players can cause hearing injuries, as the sound is generated directly in the ear canal. It is believed that different types of headphones can cause different amplifications, since they cause changes in the volume and resonance of the ear canal according to their depth. Objective: This study aimed to determine the sound pressure to which young individuals are exposed when using Personal Digital Audio Players with two types of headphones: insertion earphones and anatomical insertion earphones Materials and methods: This was an experimental study. The probe microphone measurements were made with different headphones in 54 ears (27 young individuals). The resonance peaks were also recorded. Results: A statistically significant difference was observed between the evaluated headphones, showing that anatomical insertion earphones had higher levels of sound pressure than insertion earphones for all frequencies measured. There was no correlation between the resonance peak of the closed canal and the frequency where the highest sound pressure level was obtained. There was a significant difference between ears at some frequencies with the different headphones. Conclusion: It was concluded that anatomical insertion earphones generate a higher sound pressure level than insertion earphones. .

Predictive value of middle ear aeration before second-stage operation in staged tympanoplasty with soft-wall reconstruction.

CONCLUSION: The extent of middle ear aeration before second-stage canal wall-down (CWD) tympanoplasty was correlated with postoperative middle ear stability. OBJECTIVE: To evaluate middle ear aeration before second-stage CWD tympanoplasty as a predictor of postoperative re-aeration potential and external auditory canal (EAC) stability in staged CWD tympanoplasty with soft-wall reconstruction (SWR). METHODS: Middle ear aeration was evaluated before and at 1 year after the second-stage operation in patients who underwent staged CWD tympanoplasty with SWR for middle ear cholesteatoma. Based on the computed tomography (CT) findings, middle ear aeration was graded as A when the mastoid and tympanic cavities were aerated, B when only the tympanic cavity was aerated, and C in cases with no aeration in the tympanic cavity. We also examined postoperative EAC stability. RESULTS: Forty-one ears were included. In all, 17 of 19 ears (89.5%) with grade A aeration preoperatively maintained grade A aeration postoperatively, while 5 of 18 ears (27.8%) with grade B aeration had grade A aeration, and no ear with grade C aeration had recovered grade A aeration. All ears with grade A aeration preoperatively maintained smooth EACs. EAC retraction requiring additional treatment occurred in five ears with grade B aeration and all ears with grade C aeration.

Extraocular light via the ear canal does not acutely affect human circadian physiology, alertness and psychomotor vigilance performance.

We aimed at testing potential effects of extraocular bright light via the ear canals on human evening melatonin levels, sleepiness and psychomotor vigilance performance. Twenty healthy young men and women (10/10) kept a regular sleep-wake cycle during the 2-week study. The volunteers reported to the laboratory on three evenings, 2 h 15 min before usual bedtime, on average at 21:45 h. They were exposed to three different light conditions, each lasting for 12 min: extraocular bright light via the ear canal, ocular bright light as an active control condition and a control condition (extraocular light therapy device with completely blacked out LEDs). The timing of exposure was on average from 22:48 to 23:00 h. During the 2-h protocol, saliva samples were collected in 15-min intervals for melatonin assays along with subjective sleepiness ratings, and the volunteers performed a 10-min visual psychomotor vigilance task (PVT) prior to and after each light condition. The evening melatonin rise was significantly attenuated after the 12-min ocular bright light exposure while no significant changes were observed after the extraocular bright light and sham light condition. Subjective sleepiness decreased immediately over a short period only after ocular light exposure. No significant differences were observed for mean reaction times and the number of lapses for the PVT between the three light conditions. We conclude that extraocular transcranial light exposure in the late evening does not suppress melatonin, reduce subjective sleepiness or improve performance, and therefore, does not acutely influence the human circadian timing system.

Investigation of a novel completely-in-the-canal direct-drive hearing device: a temporal bone study.

HYPOTHESIS: Whether a prototype direct-drive hearing device (DHD) is effective in driving the tympanic membrane (TM) in a temporal bone specimen to enable it to potentially treat moderate-to-severe hearing loss. BACKGROUND: Patient satisfaction with air conduction hearing aids has been low because of sound distortion, occlusion effect, and feedback issues. Implantable hearing aids provide a higher quality sound but require surgery for placement. The DHD was designed to combine the ability of driving the ossicular chain with placement in the external auditory canal. METHODS: DHD is a 3.5-mm wide device that could fit entirely into the bony ear canal and directly drive the TM rather than use a speaker. A cadaveric temporal bone was prepared. The device developed in our laboratory was coupled to the external surface of the TM and against the malleus. Frequency sweeps between 300 Hz to 12 kHz were performed in 2 different coupling methods at 104 and 120 dB, and the DHD was driven with various levels of current. Displacements of the posterior crus of the stapes were measured using a laser Doppler vibrometer. RESULTS: The DHD showed a linear frequency response from 300 Hz to 12 kHz. Placement against the malleus showed higher amplitudes and lower power requirements than when the device was placed on the TM. CONCLUSION: DHD is a small completely-in-the-canal device that mechanically drives the TM. This novel device has a frequency output wider than most air conduction devices. Findings of the current study demonstrated that the DHD had the potential of being incorporated into a hearing aid in the future.

Ear-canal reflectance, umbo velocity, and tympanometry in normal-hearing adults.

OBJECTIVE: This study compares measurements of ear-canal reflectance (ECR) to other objective measurements of middle ear function including audiometry, umbo velocity (VU), and tympanometry in a population of strictly defined normal-hearing ears. DESIGN: Data were prospectively gathered from 58 ears of 29 normal-hearing subjects, 16 females and 13 males, aged 22 to 64 yr. Subjects met all of the following criteria to be considered as having normal hearing: (1) no history of significant middle ear disease; (2) no history of otologic surgery; (3) normal tympanic membrane on otoscopy; (4) pure-tone audiometric thresholds of 20 dB HL or better for 0.25 to 8 kHz; (5) air-bone gaps no greater than 15 dB at 0.25 kHz and 10 dB for 0.5 to 4 kHz; (6) normal, type-A peaked tympanograms; and (7) all subjects had two "normal" ears (as defined by these criteria). Measurements included pure-tone audiometry for 0.25 to 8 kHz, standard 226 Hz tympanometry, ECR for 0.2 to 6 kHz at 60 dB SPL using the Mimosa Acoustics HearID system, and umbo velocity (VU) for 0.3 to 6 kHz at 70 to 90 dB SPL using the HLV-1000 laser Doppler vibrometer (Polytec Inc). RESULTS: Mean power reflectance (|ECR|) was near 1.0 at 0.2 to 0.3 kHz, decreased to a broad minimum of 0.3 to 0.4 between 1 and 4 kHz, and then sharply increased to almost 0.8 by 6 kHz. The mean pressure reflectance phase angle (∠ECR) plotted on a linear frequency scale showed a group delay of approximately 0.1 msec for 0.2 to 6 kHz. Small significant differences were observed in |ECR| at the lowest frequencies between right and left ears and between males and females at 4 kHz. |ECR| decreased with age but reached significance only at 1 kHz. Our ECR measurements were generally similar to previous published reports. Highly significant negative correlations were found between |ECR| and VU for frequencies below 1 kHz. Significant correlations were also found between the tympanometrically determined peak total compliance and |ECR| and VU at frequencies below 1 kHz. The results suggest that middle ear compliance contributes significantly to the measured power reflectance and umbo velocity at frequencies below 1 kHz but not at higher frequencies. CONCLUSIONS: This study has established a database of objective measurements of middle ear function (ECR, umbo velocity, tympanometry) in a population of strictly defined normal-hearing ears. These data will promote our understanding of normal middle ear function and will serve as a control for comparison to similar measurements made in pathological ears.

Gain affected by the interior shape of the ear canal.

OBJECTIVE: This study investigated the correlation of gain distribution and the interior shape of the human external ear canal. STUDY DESIGN: Cross-sectional study of gain measurement at the first bend and second bend. SETTING: Chang Gung Memorial Hospital and Chang Gung University. SUBJECTS AND METHODS: There were 15 ears in patients aged between 20 and 30 years (8 men/7 women) with normal hearing and middle ears. Stimulus frequencies of 500, 1000, 2000, 3000, and 4000 Hz were based on the standard clinical hearing test. Measurements closer to the tympanic membrane and the positions at the first and second bends were confirmed by using otoscope. Real ear measurement to analyze the canal resonance in human external ears was adopted. RESULTS: This study found that gain at stimulus frequencies of 4000 Hz was affected by the interior shape of the ear canal (P < .005), particularly at the first and second bends, whereas gain was only affected by the length of the ear canal for stimulus frequencies of 2000 Hz (P < .005). CONCLUSION: This study found that gain was affected not only by the length of the external auditory canal (EAC) but also by the interior shape of the EAC significantly. The findings of this study may have potential clinical applications in canalplasty and congenital aural atresia surgery and may be used to guide surgeries that attempt to reshape the ear canal to achieve more desirable hearing outcomes.

Acoustic radiation effects on bone conduction threshold measurement.

UNLABELLED: Acoustic radiation is the sound energy escape from a bone vibrator that may be detected by air conduction mechanisms. The presence of acoustic radiation may result in an unreal bone conduction threshold, promoting an unreal air/bone gap in the high frequencies. AIM: aim to analyze the acoustic radiation effect on the extension of air/bone gap at 2,000, 3,000 and 4,000 Hz. MATERIALS AND METHOD: our clinical and experimental study had a sample of 101 individuals, who matched inclusion criteria: to have an air/bone gap higher than 10 dB in the frequencies of 2,000; 3,000 and 4,000 Hz. All of them had their bone conduction threshold measured in two conditions: open ear canal and closed ear canal. RESULTS: we found that major differences between the two conditions evaluated occurred at the 4,000 Hz; data analysis showed significant difference in the extension for the air/bone gap; analysis of the number of cases of mixed hearing loss that changed to sensorineural was significant too. CONCLUSION: These studies concluded that when the MAE is occluded, the acoustic radiation phenomenon is controlled or avoided, enabling bone measures at the frequencies of 3,000 and 4,000Hz to be more accurate.

Efeitos da radiação acústica na obtenção dos limiares ósseos / Acoustic radiation effects on bone conduction threshold measurement

Radiação acústica é uma fuga da energia sonora do vibrador ósseo que pode ser detectada pela via aérea. A presença da radiação acústica poderia resultar em um limiar ósseo falso, um gap aéreo-ósseo irreal, nas frequências altas. Esse achado poderia ocorrer em pacientes sem comprometimento de orelha média e com história de doença de orelha interna, onde esse gap não é esperado. OBJETIVO: Verificar os efeitos da radiação acústica no tamanho do gap aéreo-ósseo nas frequências de 2.000, 3.000 e 4.000 Hz. MATERIAL E MÉTODO: Realizou-se estudo clínico e experimental em 101 indivíduos, com presença de gap aéreo-ósseo maior que 10 dB nas frequências de 2.000, 3.000 e/ou 4.000 Hz. Em todos participantes o limiar ósseo foi obtido nas condições: MAE aberto e fechado. RESULTADOS: Constatou-se que o gap aéreo/ósseo que mais sofreu mudança foi da frequência 4.000 Hz. Houve diferença significativa na frequência de mudança de status (misto x neurossensorial); na presença e ausência de diferenças entre via óssea fechada e aberta. CONCLUSÃO: Este estudo comprovou que quando o MAE é ocluído, o fenômeno da radiação acústica é controlado ou evitado, permitindo que as medidas ósseas para as frequências de 3.000 e 4.000 Hz sejam mais precisas.

Acoustic radiation is the sound energy escape from a bone vibrator that may be detected by air conduction mechanisms. The presence of acoustic radiation may result in an unreal bone conduction threshold, promoting an unreal air/bone gap in the high frequencies. AIM: aim to analyze the acoustic radiation effect on the extension of air/bone gap at 2,000, 3,000 and 4,000 Hz. MATERIALS AND METHOD: our clinical and experimental study had a sample of 101 individuals, who matched inclusion criteria: to have an air/bone gap higher than 10 dB in the frequencies of 2,000; 3,000 and 4,000 Hz. All of them had their bone conduction threshold measured in two conditions: open ear canal and closed ear canal. RESULTS: we found that major differences between the two conditions evaluated occurred at the 4,000 Hz; data analysis showed significant difference in the extension for the air/bone gap; analysis of the number of cases of mixed hearing loss that changed to sensorineural was significant too. CONCLUSION: These studies concluded that when the MAE is occluded, the acoustic radiation phenomenon is controlled or avoided, enabling bone measures at the frequencies of 3,000 and 4,000Hz to be more accurate.

The validity of mass body temperature screening with ear thermometers in a warm thermal environment.

Identification of people who have a fever in public places during the occurrence of emerging infectious diseases is essential for controlling disease spread. The measurement of body temperature could identify infected persons. The environment affects body temperature, but little is known about the validity of measurements under different thermal environments. Therefore, the aim of this study was to determine the validity of measuring body temperature in cold and warm environments. We recruited 50 participants aged 18-69 years (26 males, 24 females) to measure body temperature using an axillary thermometer and an ear thermometer and by infrared thermal imaging (thermography). The body temperature obtained with an axillary thermometer was used as a reference; receiver operating characteristic (ROC) analysis was conducted to determine the validity of temperatures obtained by measurement with an ear thermometer and thermography at 36.7°C (median of the axillary body temperature). The area under the ROC curve (AUC) indicates the validity of measurements. The AUC for ear thermometers in a warm environment (mean temperature: 20.0°C) showed a fair accuracy (AUC: 0.74 [95% CI: 0.64-0.83]), while that (AUC: 0.62 [95% CI: 0.51-0.72]) in a cold environment (mean temperature: 12.6°C) and measurements with thermography used in both environments (AUC: 0.57 [95% CI: 0.45-0.68] in a warm environment and AUC: 0.65 [95% CI: 0.54-0.76] in a cold environment) showed a low accuracy. In conclusion, in a warm environment, measurement of body temperature with an ear thermometer is a valid procedure and effective for mass body temperature screening.

Acoustic recordings in human ear canals to sounds at different locations.

The head and pinna shape the sound reaching the tympanum. We explored this signal transformation in humans and a mini basketball for different sound locations in an anechoic chamber. For humans, we embedded microphones in ear molds that were custom fitted to the subject's ear canal. For the ball, the microphones were flush with the surface at +/- 90 degrees azimuths on the equator. Sounds were generated with a custom point source. In the ball, the signal level was nearly flat across frequency, with no gains. In contrast, in the ears, signal level changed in a complex way across frequency, with considerable gains. For frequencies < 2 kHz, the interaural level difference (ILD) increased with decreasing distance similarly in the human ears and ball. For frequencies > 4 kHz, ILDs in the human ears were larger and more complex than those in the ball such that the human ILDs were nonmonotonic with distance whereas the ball ILDs were monotonic with distance.

[The exploration of TTAG method in determinating the states of eustachian tube function of healthy group].

OBJECTIVE: To explore the feasibility and validity of tubo-tymanoaerodynamicgraphy (TTAG) determinating the Eustachian tube function of health adult group. METHOD: The ventilation function of Eustachian tube was measured by the TTAG method in health adult group (132 ears), the results and the graphs were also analyzed. RESULT: The positive rate in health adult group using Valsalva method was 93.93% (124/132). The positive ears were divided into type I and type II, the mean value of nasopharynx press of type I and II has no significant differences (P>0.05), but the mean value of external auditory canal press had significant differences (P<0.01). CONCLUSION: TTAG method has the clinical value in determinating the states of Eustachian tube function of health group.

Dissociation between distortion-product and click-evoked otoacoustic emissions in sheep (Ovis aries).

Distortion-product otoacoustic emissions (DPOAEs) were weak or absent in about one-third of sheep (Ovis aries) of both sexes tested for otoacoustic emissions (OAEs) even though their click-evoked OAEs (CEOAEs) seemingly were typical of other sheep of the same sex. Various pieces of evidence suggest that the absence of measurable DPOAEs was unlikely to be attributable to anesthetic effects, a poorly located probe tip, a pressure differential between middle and outer ears, season of the year, body position during testing, temperature effects, or previous medical history. Sheep apparently can exhibit a marked dissociation between DPOAEs and CEOAEs. In those sheep having measurable DPOAEs, the DPOAEs were stronger in males than in females, which is the opposite direction of effect from the CEOAEs measured in these same sheep and in humans. In female sheep exposed to higher-than-normal levels of androgens during gestation, the measurable DPOAEs were stronger than in untreated females. Although this also was the opposite direction of effect from expected, it still was a shift in the male direction, in accord with past findings about the masculinizing effects of androgens on OAEs. In sheep, androgen exposure appears to have different effects on the mechanisms underlying DPOAEs from those underlying CEOAEs.