• 한국소음진동공학회논문집
• /
• 제21권9호
• /
• pp.842-849
• /
• 2011

The human ear canal amplifies the sound pressure level at specific frequency bands. The characteristics of the ear canal are very similar to those of curved cylindrical tube. In this study, the characteristics of sound transfer in human ear canal were measured and the acoustical space of ear canal was reproduced from the canal cavity geometry. For the measurement of sound transfer function in ear canal, a probe microphone and a reference microphone were used. The sound transfer functions were measured for 5 human subjects. To reproduce the acoustical space of the ear canal, two kinds of ear simulator were designed. The first one is a straight cylindrical tube type and the other is a real-shape ear of which geometry was taken from a micro-CT scanning of a human ear. The characteristics of the reproduced apparatus were compared with those of the human and a commercial ear simulator, RA0045 of G.R.A.S. Inc. The comparison results show that the developed apparatus well represent the ear canal characteristics in the low frequency, but have limited coincidence in level over high frequency range.

• 말소리와 음성과학
• /
• 제1권3호
• /
• pp.151-154
• /
• 2009

The external ear generates resonance gain because of anatomical characteristics. The ear canal resonance is influenced by the length and volume of the ear canal, the pinna, the concha cavity, the body trunk, and the speed of sound wave. This study is focus on the influence of the volume of ear canal. 17-healthy-adult (32 ears) were participated. They did not have any medical and ear disease history. The maximum resonance frequency of the ear canal was 2675 (${\pm}265$) Hz at azimuth $0^{\circ}$ and 2784 (${\pm}268$) Hz at azimuth $45^{\circ}$. The resonance gain was 18.1 (${\pm}3.9$) dB at azimuth $0^{\circ}$ and 17.9 (${\pm}3.8$) dB at azimuth $45^{\circ}$, respectively. The ear canal volume was 0.78 (${\pm}0.2$) cc and 1.32 (${\pm}0.8$) cc including static compliance. The ear canal resonance was changed depending on the ear canal volume. It was also statistically correlated at azimuth $0^{\circ}$ (p=0.038) and $45^{\circ}$ (p=0.013), respectively. The resonance gain was not correlated with the ear canal volume. The change of resonance frequency according to the ear canal volume will be useful information in the field of audiological rehabilitation especially for hearing aids fitting. In addition, we expected this study can provide the basic information for the study of the external ear resonance characteristics.

• 한국임상수의학회지
• /
• 제21권2호
• /
• pp.149-153
• /
• 2004

This study was to determine the procedure for ultrasonographic imaging of the canine external ear canal(ECC). By infusion of warm saline solution into the ear canal, a real-time B mode ultrasonographic examination of the ECC was performed in five healthy Beagle dogs and two dogs with severe otitis externa. The ultrasonography was very useful to detect the structures of the ECC and the tympanic membrane. An 11 NHz linear probe was permitted to assess an anechoic lumen of the ECC and a hyperechoic cartilage surrounding the ear canal. In two dogs with otitis externa, it could be assessed the ECC with ultrasonography without ear cleansing. A lumen of the ECC was irregular and a cerumen could be seen, but edematous inflammatory changes of the ECC could not be identified. The results suggest that ultrasonography of the ECC with an 11 NHz linear probe after infusing the saline solution into the ear canal may be an accurate, non-invasive, rapid, and widely available method for assessment of the ear canal diseases such as otitis externa, polyp, stenosis, hyperplasia, and foreign body in dogs.

• 한국임상수의학회지
• /
• 제21권2호
• /
• pp.97-101
• /
• 2004

This study was aimed for ultrasonographic assessment of the tympanic membrane and the tympanic bulla in five healthy Beagle dogs. To improve an ultrasonographic image, the ear canal was filled with warm saline, and an 11 MHz linear probe and a 6.5 MHz convex probe were used. The structures of ear component such as ear canal, ear cartilage and tympanic membrane were easily identified. Especially, tympanic membrane was presented as a reflaction surface which was resulted from the different acoustic impedence between the fluid-filled anechoic ear canal and the gas-filled hyperechoic tympanic cavity in normal dogs. In five left-side ears, the saline was infused into the external ear canal after the tympanic membrane had been ruptured experimentally. Both anechoic fluid-filled ear canal and tympanic cavity were clearly identified. In five right-side ears, the surgically fluid-filled tympanic cavity was imaged as a hypoechoic oval shaped structure. When tympanic cavity and ear canal have been contained with fluid, it was difficult to identify whether the tympanic membrane was ruptured or not. For assessment of the ear structure with ultrasonography, the 11 MHz linear probe was considered as an optimal equipment for a serial assessment of ear canal, tympanic membrane and tympanic bulla whereas the 6.5 MHz convex probe was suitable to assess the tympanic cavity. The results suggest that ultrasonography with saline infusion into the ear canal can be used to find the intactness of the tympanic membrane and to assess the fluid- filld tympanic bulla.

• 한국임상수의학회지
• /
• 제38권3호
• /
• pp.159-162
• /
• 2021

A 5-year-old, intact male, poodle dog with right external auditory canal obstruction and subaural mass was presented. Physical examination revealed that right external auditory canal opening was absent and right head tilt was identified. Aspiration in right subaural mass revealed a small amount of dark brown exudate. Streptococcus canis and Staphylococcus spp. were identified on the microbial culture. Radiography of the skull was revealed absence of air-filled ear canal at the right external ear canal (EEC) level. Computed tomography (CT) revealed well capsulated, hypoattenuated mass in the right EEC region. On the contrast enhanced CT images, rim enhancement around the mass and ear canal obstruction were identified. Fluid attenuated material filled with right bulla. Mild thickening of the right tympanic bulla wall with mild lytic lesion of the ventral wall were found. Based on the images findings, the case was tentatively diagnosed as right external auditory canal atresia with otitis media. Total ear canal ablation and lateral bulla osteotomy was performed. The entire ear canal was removed, numerous hair in the canal and the thickening wall were founded. Right ear canal was sent for histopathological evaluation and found to otitis externa. The patient was followed up for two weeks and there were no complications. This report described the CT diagnosis of right EEC atresia with otitis media rarely reported in small breed dogs.

• Parasites, Hosts and Diseases
• /
• 제55권5호
• /
• pp.565-568
• /
• 2017

An oval-shaped mass with a smooth surface was found in the ear canal of a 22-month-old male infant. Although the mass appeared to be almost entirely blocking the ear canal, it was successfully removed under a surgical microscope without general anesthesia at the outpatient department. Under an optical microscope with hematoxylin and eosin staining, the specimen was observed to have a cuticle with a serrated surface and a pore canal, as well as parts of the capitulum, salivary glands, muscles, midgut, and the legs. The specimen was identified as a hard tick of the family Ixodidae, based on gross and histological findings. This paper is the first report in Korea on the diagnosis and treatment of a tick bite in the ear canal.

• 말소리와 음성과학
• /
• 제9권1호
• /
• pp.49-53
• /
• 2017

Formant frequencies depend on the position of tongue, the shape of lips, and larynx. In the auditory system, the external ear canal is an open-end resonator, which can modify the voice characteristics. This study investigates the effect of the real ear on formant frequencies. Fifteen subjects ranging from 22 to 30 years of age participated in the study. This study employed three corner vowels: the low central vowel /a/, the high front vowel /i/, and the high back vowel /u/. For this study, the voice of a well-educated undergraduate who majored in speech-language pathology, was recorded with a high performance condenser microphone placed in the upper pinna and in the ear canal. Paired t-test showed that there were significant difference in the formant frequencies of F1, F2, F3, and F4 between the free field and the real ear. For /a/, all formant frequencies decreased significantly in the real ear. For /i/, F2 increased and F3 and F4 decreased. For /u/, F1 and F2 increased, but F3 and F4 decreased. It seems that these voice modifications in the real ear contribute to interpreting voice quality and understanding speech, timbre, and individual characteristics, which are influenced by the shape of the outer ear and external ear canal in such a way that formant frequencies become centralized in the vowel space.

• 한국융합학회논문지
• /
• 제10권3호
• /
• pp.73-79
• /
• 2019

머리 측두부 디지털 영상 및 통신 표준 영상을 이용한 외이도 길이, 상하 굴곡각도, 내 외경 비율에 따른 음향민감도를 외이도 모델링으로 시뮬레이션하고 측정하였다. 실험은 인간 가청주파수 기준으로 200Hz씩 증가하면서 1 파스칼의 압력으로 일정하게 전달된 주파수를 고막 음향크기로 나타내어 그 측정값들을 선형과 이차곡선 회귀분석으로 나타내었다. 그 결과 외이도 길이는 길수록, 외 내경 둘레의 비율은 높을수록 낮은 주파수에서 빠른 음향적 반응을 나타내었다. 회귀분석을 이용한 메타모델의 음향민감도 상관관계는 외이도 길이가 77%, 외 내경 비율 5%의 영향으로 나타났지만 상하 굴곡각도는 특별한 관계를 나타내지 못하였다. 이로써 인간의 청각음향 민감도는 외이도 길이가 길수록, 외 내경 둘레의 비율 차이가 높을수록 낮은 주파수에서 빠르게 반응하는 인자임을 알 수 있었다.

• 한국임상수의학회지
• /
• 제36권5호
• /
• pp.266-270
• /
• 2019

A 13-year-old spayed female American cocker spaniel dog was submitted to an animal hospital with a mass from left ear canal and enlarged left parotid lymph node. Given one-year history of odorous exudates and chronic otitis externa, total ear canal ablation was performed. Grossly, because of the neoplastic mass in both inner and outside of annular cartilage in external ear, vertical ear canal was severely narrowed. Histologically, there were numerous proliferated glands in the ear canal mass. Many neoplastic glands contained secretory vesicles on the free margin and necrotic cellular debris. Severe multifocal necrosis and strong invasion were also observed throughout the mass. Massive metastatic foci of glandular structures originated from ceruminous gland were presented in the enlarged parotid lymph node. Neoplastic glandular epithelia contained PAS-positive diastase-resistant eosinophilic cytoplasmic granules. Immunohistochemically, the neoplastic cells showed positive reactions for cytokeratin (CK) 7 and negative for CK 5/6. Based on the clinical implication and gross findings, histopathology and immunohistochemistry, this case was diagnosed as metastatic ceruminous gland adenocarcinoma in the American cocker spaniel.

• 대한기관식도과학회:학술대회논문집
• /
• 대한기관식도과학회 1976년도 제10차 학술대회연제 순서 및 초록
• /
• pp.86.3-86
• /
• 1976

외이도의 편평상피암은 드믄 질환으로 진단이 내려질 때는 이미 상당히 침범되어 외이도와 중이가 다 같이 침범되어 있는 경우가 대부분이다. 최근 저자들은 외이도에 발생한 편평상피암 1례를 경험하고 외이도의 광범위한 절제술 및 유양돌기 절개근치술과 술후 방사선 치료를 하였기에 문헌적 고찰과 더불어 보고하는 바이다.