Left Ear Canal Research Articles

Treacher Collins Syndrome 2 caused by a novel pathogenic variant in PLOR1D: clinical report and literature review

Objective: To investigate the clinical features, molecular etiology, and treatment of a family with Treacher Collins Syndrome 2 (TCS2). Methods: Information of the proband (female, 8 years old) including medical history and family history was collected. Physical examination and examinations concerning laboratory, audiology, and radiology were performed on the proband. Physical examination was also performed on the family members. Genomic DNA of proband was extracted for whole exome sequencing, and then the genomic DNA of family members was extracted for Sanger sequencing. POLR1D and TCS2 related literatures published before August 31,2023 were searched and sifted in PubMed and CKNI databases. The clinical characteristics of TCS2 were summarized. Results: The proband had poor hearing since childhood, with pure tone audiometry indicating conductive hearing loss. She had a smaller jaw, bilateral preauricular fistulas and cup-shaped ear deformities. Temporal bone CT scan revealed deformities in the left external ear canal, bilateral middle ear and inner ear. A bone-conduction hearing aid device was surgically implanted, resulting in restoration of almost normal hearing levels. The proband's mother also had a slightly smaller jaw. Genetic analysis revealed a novel heterozygous variant NM_015972.4:c.38_47del in the POLR1D gene in the proband, which was inherited from her mother. A review of the literature revealed no clear evidence of genotype-phenotype correlation in TCS2. Conclusions: Molecular diagnosis plays a vital role in the diagnosis of TCS2. Patients with normal facial phenotype may be carriers of pathogenic variants in the POLR1D gene and have the risk of passing it to the offsprings with complete penetrance. Proper bone conductive hearing devices can improve the quality of life of TCS2 patients.

Reduced unilateral sweating caused by varicella zoster virus infection: a case report

BackgroundHerpes zoster is an infectious skin disease caused by the reactivation of the varicella zoster virus (VZV), which has been latent in the posterior root ganglia of the spinal cord or cranial ganglia for an extended period. Neurological complications caused by herpes zoster include aseptic meningitis, white matter disease, peripheral motor neuropathy, and Guillain-Barré syndrome. However, reduced unilateral sweating caused by the VZV is very rare.Case PresentationThis article reports the case of a 34-year-old woman who was admitted to our hospital with sore throat, dizziness, and reduced sweating on the left side of her body. Physical examination found herpes lesions on the left upper lip and left external ear canal (scabbed) and reduced sweating on the left side of the body. Head magnetic resonance imaging (MRI) with contrast showed no abnormalities. After a lumbar puncture, the patient was diagnosed with viral meningitis by VZV infection. The electromyographic skin sympathetic reflex indicated damage to the left sympathetic nerve.ConclusionsSecondary unilateral sweating reduction is a rare neurological complication of herpes zoster, caused by damage to the autonomic nervous system. Literature review and comprehensive examination indicated that the reduced unilateral sweating was due to the activation of latent herpes zoster virus in the autonomic ganglia which has damaged the autonomic nervous system. For patients who exhibit acute hemibody sweat reduction, doctors should consider the possibility of secondary autonomic nervous system damage caused by herpes zoster.

External auditory canal atresia affecting the horizontal canal of a 2‐year‐old Labrador Retriever dog

AbstractA 2‐year‐old, female neutered, Labrador Retriever dog was presented with left otalgia. Otoscopic examination revealed a blind ending left external ear canal. Magnetic resonance imaging confirmed an abrupt narrowing of the lateral aspect of the horizontal canal, medial to which the remaining horizontal ear canal and middle ear cavities contained well‐delineated, homogenous, T2w, fluid‐attenuated inversion recovery and T1w hyperintense, non‐contrast enhancing material. A diagnosis of external auditory canal atresia was made based on the imaging findings. Considering the patient's age and absence of preceding trauma, a congenital cause was considered most likely. Surgical treatment by way of a total ear canal ablation with lateral bulla osteotomy was performed. At the re‐check appointment, the surgical site had healed well and there were no associated complications noted; a telephone call with the owner 5 months later documented no clinical concerns.

An Innovative Therapy by Changing the Gut Microbiome for the Dual Post-Operative Complications of the Recurrent Methicillin-Resistant Staphylococcus aureus (MRSA) Infections in the Residual Type II First Branchial Cyst and Facial Nerve Palsy

A very unusual, interesting, and challenging case of a 24-year-old female who was born with three openings in the neck. The patient had chronic abdominal gaseous distention, recurrent abdominal pain, and constipation since early infancy. The patient presented in emergency with acute painful red, hot, and tender swelling in the left upper cervical area. Laboratory studies showed high inflammatory markers and a provisional diagnosis of abscess with a sinus was made. The patient underwent an emergency incision and drainage. Sinus recurred and a sinogram showed it to be a residual cyst in the left submandibular salivary gland. The total cyst excision was attempted with resultant recurrence and grade IV facial nerve palsy. Post-operatively recurrent infections caused by Methicillin-resistant Staphylococcus aureus (MRSA) required several courses of oral and intravenous broad-spectrum antibiotics with several hospital admissions with no resolution in sight. Subsequent ultrasound and magnetic resonance imaging showed a residual infected cyst, cutaneous sinus, and a fistula opening in the left ear canal. A diagnosis of branchial cyst type II of the first brachial cleft remnant with a fistula was established with bilateral branchial fistulas of the second branchial remnants and the associated colorectal hypoganglionosis based on radiological studies. The patient refused any further operative interventions. Therefore, the option of conservative treatment of hypoganglionosis with holobiotics consisting of prebiotics, probiotics and postbiotics, laxatives, dietary changes, lifestyle modifications, and dietary supplements started. All antibiotics were stopped. These therapies resulted in the resolution of residual first branchial remnants and recurrent MRSA infections with the improvement in the facial nerve palsy from grade IV to grade III-IV together with an excellent cosmetic and functional result. The patient is doing well at follow-ups being infection-free for 18 months and repeat contrast-enhanced computed tomogram (CECT) has shown complete resolution of the residual cyst, sinus, and fistula with fibrosis.

OTITIS EXTERNA DUE TO COMPLICATION OF OTODECTES CYNOTIS, BACTERIA, AND MALASSEZIA SP. ACCOMPANIED BY SCABIOSIS IN DOMESTIC CAT

Otitis externa is an inflammatory state of the external ear canal due to the colonization of microorganisms (bacteria, fungi, or parasites). Scabiosis in cats is a highly contagious disease caused by the Notoedres cati mite. The purpose of this article is to provide information on the diagnosis, treatment, and therapeutic evaluation of otitis externa with scabiosis in a local cat. The case animal was a 2-year-old female Oren, weighing 2.75 kg and with orange, black, and white hair. The cat was brought to the Teaching Animal Hospital, Faculty of Veterinary Medicine, Udayana University with complaints of frequent scratching of the right and left ears since 1 month ago. On physical examination, dark brown cerumen was found in the right and left ear canals. In the supporting examination, ear swab found Otodectes cynotis mite cytology ear cerumen observed the presence of bacteria in the form of cocci and bacilli, and Malassezia sp. While in the examination of skin scrapings found Notoedres cati mite. Based on anamnesis, clinical examination and supporting examination, the case cat was diagnosed with bilateral otitis externa and scabiosis with a prognosis of fausta. For the treatment of otitis, the therapy given was topical treatment using antiparasitic permethrine, antibiotic neomycin sulfate, antifungal nystatin and anti-inflammatory triamnicolone acetonide given once a day for 7 days. For the treatment of scabiosis, the therapy given is Ivermectin injection at a dose of 0.3 mg/kg BW subcutaneously twice administered at 14-day intervals. As symptomatic therapy, diphenhydramine was given at a dose of 1 mg/kg BW intramuscularly, followed by diphenhydramine HCL orally at a dose of 2 mg/kg BW given twice a day for 7 days as an antihistamine to treat pruritus. Topical therapy was also given by bathing with sulfur soap twice a week for two weeks. Evaluation was carried out on day 10 where the case cat showed a continuously improving condition characterized by the case cat rarely scratching the ears, the crusts on the skin had begun to thin, and the parts that were initially alopecia had begun to grow hair.

Comparison of the quantity and antimicrobial activity of host defence peptides in ear canals between healthy and atopic dogs: A preliminary study.

Host defence peptides (HDPs) are involved in cutaneous immune defence. The secretion of HDPs in the ears of healthy normal and noninfected atopic dogs has not been measured. The aim of this study was to quantify the concentrations of β-defensins (cBD3)-like and cathelicidin (cCath) HDPs in ears of healthy and atopic dogs without infectious otitis, additionally to evaluate the antimicrobial effect of the HDPs obtained. Ten healthy and 20 atopic dogs with mild inflammatory, noninfectious otitis were included. Absence of infection was determined by cytological evaluation, and the severity of clinical signs, if present, was assessed by a previously validated score (Otitis Externa Scoring System for Clinical Study, OTIS-3). The left ear canal of each dog was rinsed with 2 mL of sodium phosphate buffer. The solution obtained was analysed by enzyme-linked immunosorbent assay to quantify HDPs. Additionally, aural secretions were incubated with two concentrations (5 × 105 and 5 × 104 colony-forming units/mL) of Staphylococcus pseudintermedius and the bacterial density measured after 24 h of incubation. Data were statistically analysed. Significance was set as p ≤ 0.05. There was a significantly lower concentration of HDPs from atopic ears when compared with those from normal healthy dogs (cBD3-like: p = 0.0007; cCath: p = 0.049). There was minimal to variable antimicrobial activity in the aural secretions of both groups. This study showed, for the first time, that the ear canals of atopic dogs with mild noninfectious otitis contain a lower concentration of cBD3-like and cCath HDPs than those of healthy dogs with normal ears. A consistent antimicrobial activity was not present in the aural secretions from either group.

External Auditory Canal Mass: A Case Series of Squamous Cell Carcinoma

Introduction: Squamous cell carcinoma of the temporal bone is extremely rare comprising 0.2% of all tumors of head and neck. Symptoms are nonspecific and may be mistaken for other more benign conditions as otitis, cholesteatoma and polyp. Hence, this condition may present as a diagnostic challenge. Case Discussion: We describe a case series of three patients who presented with external auditory canal (EAC) mass. The most common signs and symptoms are pruritus, decreased hearing and yellowish discharge. They were initially treated with otic antibiotics which afforded no relief. The first case is a 51 year-old female who underwent wide excision of the right ear canal and middle ear mass and right temporal craniotomy. Histopathology showed moderately differentiated squamous cell carcinoma with temporal tumor and subdural extension consistent with metastasis. The second case is a 53 year-old male who refused surgical management. He was non-compliant with work-up and follow-up and later on presented with left facial asymmetry and headache. CT scan showed a left inner and middle ear canal mass with extension to the auditory canal and protrusion into the left cerebellar hemisphere. Punch biopsy of the left EAC mass was done and pathologic report showed well-differentiated squamous cell carcinoma. Lastly, a 54 year old male who underwent Radical mastoidectomy with histopathology reports of a moderately differentiated squamous cell carcinoma. Conclusion: Standard treatment modality is still unclear because of the rarity of this condition. However, surgical resection with negative margins followed by concurrent chemotherapy and radiation is the most commonly performed approach1. For the above-mentioned patients, concurrent chemotherapy and radiation therapy was given which showed significant treatment response.

Auditory Mirror Therapy for Tinnitus: A Pilot Study.

Tinnitus, the phantom perception of sound, shares many properties with phantom limb pain, in that both may arise as a consequence of sensory deprivation. Prediction errors in multisensory integration, such as induced with mirror box therapy in phantom pain, can reduce phantom percepts. We evaluated if a device that swaps sound from the right pinna to the left ear canal, and from the left pinna to the right ear canal, can reduce tinnitus. We call this auditory mirror therapy (AMT). Uncontrolled trial. Twenty subjects with chronic tinnitus. An AMT device consisting of a modified ear defender device with microphones that swaps sounds from left pinna to the right ear canal and from the right pinna to the left ear canal. Participants used the device at home for 2 weeks. Tinnitus Handicap Inventory (THI), Tinnitus Reaction Questionnaire, and visual analog scale ratings of symptoms were collected at baseline and posttreatment. Repeated measures t-test were performed, Bonferroni corrected for multiple comparisons. There was a significant reduction in THI and in awareness of tinnitus after the AMT intervention. Exposing the audiovisual integration system to prediction errors can help retrain phantom percepts and reduce tinnitus handicap. Further studies on this concept are warranted.

Bilateral Ear Acoustic Authentication: A Biometric Authentication System Using Both Ears and a Special Earphone

In existing biometric authentication methods, the user must perform an authentication operation such as placing a finger in a scanner or facing a camera. With ear acoustic authentication, the acoustic characteristics of the ear canal can be used as biometric information. Therefore, a person wearing earphones does not need to perform any authentication operation. Existing studies which use the acoustic characteristics of the ear canal as biometric information only measure the characteristics of one ear. However, the acoustic characteristics of the human ear canal can be measured from both ears. Hence, we proposed a new method for acoustic authentication based on the ability to measure the acoustic characteristics of the ear canal from both ears. The acoustic characteristics of the ear canal of 52 subjects were measured. Comparing the acoustic characteristics of the left and right ear canals, a difference in the signal between the left and right ear was observed. To evaluate the authentication accuracy, we calculated the evaluation indices of biometric authentication, equal error rate (EER), and area under curve (AUC). The EER for bilateral ear acoustic authentication using signals from both ears was 0.39%, which was lower than that of a single ear. The AUC was 0.0016 higher for bilateral ear acoustic authentication. Therefore, the use of bilateral signals for ear acoustic authentication was proved to be effective in improving authentication accuracy.

Ear microbiota and middle ear disease: a longitudinal pilot study of Aboriginal children in a remote south Australian setting

BackgroundOtitis media (OM) is a major disease burden in Australian Aboriginal children, contributing to serious long-term health outcomes. We report a pilot analysis of OM in children attending an outreach ear and hearing clinic in a remote south Australian community over a two-year period. Our study focuses on longitudinal relationships between ear canal microbiota characteristics with nasopharyngeal microbiota, and clinical and treatment variables.ResultsMiddle ear health status were assessed in 19 children (aged 3 months to 8 years) presenting in remote western South Australia and medical interventions were recorded. Over the two-year study period, chronic suppurative OM was diagnosed at least once in 7 children (37%), acute OM with perforation in 4 children (21%), OM with effusion in 11 children (58%), while only 1 child had no ear disease. Microbiota analysis of 19 children (51 sets of left and right ear canal swabs and nasopharyngeal swabs) revealed a core group of bacterial taxa that included Corynebacterium, Alloiococcus, Staphylococcus, Haemophilus, Turicella, Streptococcus, and Pseudomonas. Within-subject microbiota similarity (between ears) was significantly greater than inter-subject similarity, regardless of differences in ear disease (p = 0.0006). Longitudinal analysis revealed changes in diagnosis to be associated with more pronounced changes in microbiota characteristics, irrespective of time interval. Ear microbiota characteristics differed significantly according to diagnosis (P (perm) = 0.0001). Diagnoses featuring inflammation with tympanic membrane perforation clustering separately to those in which the tympanic membrane was intact, and characterised by increased Proteobacteria, particularly Haemophilus influenzae, Moraxella catarrhalis, and Oligella. While nasopharyngeal microbiota differed significantly in composition to ear microbiota (P (perm) = 0.0001), inter-site similarity was significantly greater in subjects with perforated tympanic membranes, a relationship that was associated with the relative abundance of H. influenzae in ear samples (rs = − 0.71, p = 0.0003). Longitudinal changes in ear microbiology reflected changes in clinical signs and treatment.ConclusionsChildren attending the ear and hearing clinic in a remote Aboriginal community present with a broad spectrum of OM conditions and severities, consistent with other remote Aboriginal communities. Ear microbiota characteristics align with OM diagnosis and change with disease course. Nasopharyngeal microbiota characteristics are consistent with the contribution of acute upper respiratory infection to OM aetiology.

Langerhans Cell Histiocytosis of the Temporal Bone in Children: Two Cases Report

Langerhans cell histiocytosis is a rare hematologic disease due to multiplication and accumulation of Langerhans cells, which are immature dendritic cells. The clinical presentation is highly variable and can range from isolated, self-healing skin or bone lesions to life-threatening multisystem disease. We report 2 cases confirmed by Histological and immunohistochemical evaluation of temporal bone biopsies. The first case is a 2-year-old child with chronic bilateral otorrhea and polyuria-polydipsia syndrome. Physical examination showed bilateral retroauricular redness and induration with filling all of the right and left external ear canal. Computed tomography showed osseous lysis of the temporal bone bilaterally. Magnetic resonance imaging of the brain showed the presence of pituitary infiltration. The second case is 2-year-old girl with chronic left otorrhea. Clinical examination objectified the presence of redness and induration in the left mastoid with the presence of an inflammatory polyp filling the entire left external auditory canal. Computed tomography revealed a left temporal bone lysis. Both patients were treated with chemotherapy.

Acute mastoiditis with facial paralysis as initial symptom of acute myeloid leukemia relapse: a rare case report

BackgroundExtramedullary involvement of leukemia usually occurs in the skin and central nervous system. Isolated leukemic involvement of the temporal bone is a very uncommon situation, and it is seen frequently concomitant to hematologic or molecular relapse.Case presentationAn 8-year-old male with acute myeloid leukemia (AML) M2 with t (8,21) (FAB classification) in remission for 2 years was referred to our clinic with severe ear pain, persistent ear discharge, and hearing loss with left facial paralysis for 4 days. Physical examination revealed purulent ear discharge with severe edema of the left ear canal. The temporal computed tomography revealed otomastoiditis. However, temporal magnetic resonance imaging demonstrated a 9 × 6 × 5 mm contrast-enhancing lesion in the internal acoustic canal and thickening in VIIth and VIIIth cranial nerves. Mastoidectomy was performed for exploration and biopsy. The histopathological results of the mastoid bone and soft tissue samples revealed a relapse of AML. One month after the first chemotherapy regime, ear discharge stopped and facial palsy recovered totally. However, the patient died 9 months after the diagnosis of relapse.ConclusionTemporal bone relapse should be suspected in AML patients with symptoms of otomastoiditis and facial palsy. Further investigations including radiological examinations, surgery, and biopsy for avoiding misdiagnosis and delay in treatment are needed.

External auditory exostoses, repetitive aquatic activity and increasing social complexity in Chalcolithic Cyprus: Specialists of the sea?

AbstractExternal auditory exostoses (EAEs) are dense osseous hyperostoses that protrude into the external auditory canal and are associated with repetitive aquatic activity. Clinically, the aetiology of EAEs is attributed to prolonged exposure to cold water through activities including swimming, surfing, diving, kayaking and sailing. The prevalence and distribution of EAEs within a particular archaeological context informs on human–environment interactions, activity and behavioural differences between the sexes, habitual aquatic activity (e.g., fishing, diving, swimming, bathing, seafaring, littoral zone resource procurement), marine and aquatic resource exploitation and subsistence patterns. This study aims to assess the prevalence of EAEs within a prominent Chalcolithic skeletal assemblage from Souskiou‐Laona, in southwestern Cyprus. Sixty‐five auditory canals were examined macroscopically and microscopically to confirm the presence or absence of EAEs. Five adult individuals present EAEs (right auditory canals; left ear canals not sufficiently preserved) with a prevalence of 15.1% of all sufficiently preserved right ear canals (33). EAE prevalence is 25% in males and 14.2% in females. Earlier burials on the site, represented by bonestack (commingled) crania, display EAEs at 14.8% prevalence, whereas the last burials (articulated skeletons) show a prevalence of 16.7%. Malacological evidence from Souskiou‐Laona cemetery attests marine resource procurement, including activity at the littoral zone. The EAEs at Souskiou‐Laona likely reflect the diachronic exploitation of marine resources at the south coast of Cyprus from the foundation of the cemetery to the latest burials before abandonment of the site. Both males and females participated in these repetitive aquatic activities. The differential expression of EAEs in the population as a whole, and the different prevalences between males and females, may be interpreted in the context of increasing specialisation and social complexity during the Chalcolithic, consistent with the development of other specialised, standardised and gender‐differential activities during this time period.

Langerhans Cell Histiocytosis of the Temporal Bone in a Child with Central Diabetes Insipidus

Langerhans cell histiocytosis is a rare clonal disease defined by an accumulation of dendritic cells with Langerhans cell immunological properties within different organs of the body. We intend to describe a new case of Langerhans cell histiocytosis of the temporal bone in a child with central diabetes insipidus. The child presented the polyuria-polydipsia syndrome for 6 months with Chronic bilateral otorrhea. On physical examination,there were bilateral retroauricular redness and induration. The otoscopy visualized inflammatory polyps filling all of the right and left external ear canal. Biological exploration confirmed the central diabetes insipidus. Magnetic resonance imaging of the brain showed the presence of pituitary infiltration. Computed tomography showed osseous lysis of the temporal bone bilaterally. A retroauricular biopsy was performed under general anesthesia. Histological and immunohistochemical evaluation confirmed the diagnosis of Langerhans cell histiocytosis

In-Ear EEG Based Attention State Classification Using Echo State Network.

It is important to maintain attention when carrying out significant daily-life tasks that require high levels of safety and efficiency. Since degradation of attention can sometimes have dire consequences, various brain activity measurement devices such as electroencephalography (EEG) systems have been used to monitor attention states in individuals. However, conventional EEG instruments have limited utility in daily life because they are uncomfortable to wear. Thus, this study was designed to investigate the possibility of discriminating between the attentive and resting states using in-ear EEG signals for potential application via portable, convenient earphone-shaped EEG instruments. We recorded both on-scalp and in-ear EEG signals from 6 subjects in a state of attentiveness during the performance of a visual vigilance task. We have designed and developed in-ear EEG electrodes customized by modelling both the left and right ear canals of the subjects. We use an echo state network (ESN), a powerful type of machine learning algorithm, to discriminate attention states on the basis of in-ear EEGs. We have found that the maximum average accuracy of the ESN method in discriminating between attentive and resting states is approximately 81.16% with optimal network parameters. This study suggests that portable in-ear EEG devices and an ESN can be used to monitor attention states during significant tasks to enhance safety and efficiency.

Exposure to blast shock waves via the ear canal induces deficits in vestibular afferent function in rats

The ears are air-filled structures that are directly impacted during blast exposure. In addition to hearing loss and tinnitus, blast victims often complain of vertigo, dizziness and unsteady posture, suggesting that blast exposure induces damage to the vestibular end organs in the inner ear. However, the underlying mechanisms remain to be elucidated. In this report, single vestibular afferent activity and the vestibulo-ocular reflex (VOR) were investigated before and after exposure to blast shock waves (∼20 PSI) delivered into the left external ear canals of anesthetized rats. Single vestibular afferent activity was recorded from the superior branch of the left vestibular nerves of the blast-treated and control rats one day after blast exposure. Blast exposure reduced the spontaneous discharge rates of the otolith and canal afferents. Blast exposure also reduced the sensitivity of irregular canal afferents to sinusoidal head rotation at 0.5–2Hz. Blast exposure, however, resulted in few changes in the VOR responses to sinusoidal head rotation and translation. To the best of our knowledge, this is the first study that reports blast exposure-induced damage to vestibular afferents in an animal model. These results provide insights that may be helpful in developing biomarkers for early diagnosis of blast-induced vestibular deficits in military and civilian populations.

Cerebral Abscess with Rupture into the Ventricles due to Chronic Otitis Media

This 43-year-old man with a known history of schizophrenia presented with a one-week history of left ear pain accompanied by a purulent discharge from the external auditory canal over the last 3 days. Shortly afterwards he became confused.
 On direct examination, the left ear canal was oedematous containing granulation tissue.
 This 43-year-old man with a known history of schizophrenia presented with a one-week history of left ear pain accompanied by a purulent discharge from the external auditory canal over the last 3 days. Shortly afterwards he became confused.
 On direct examination, the left ear canal was oedematous containing granulation tissue.

Three-Dimensional Changes of the Auditory Canal in a Three-Year Period during Adolescence Using CBCTs.

Purpose There is a lack of identifying suitable regions in the head that can be used for three-dimensional superimposition techniques. For this reason, with the use of cone-beam computed tomography (CBCT), the ear canals were analyzed to verify changes during a period of three years in the adolescent years. Methods CBCTs from fifty-six patients (ages: 10 to 20) were used to landmark the anatomy of the ear canals. Each patient was analyzed using two CBCT reconstructions that were taken approximately three years apart. AVIZO® software was used to locate 28 landmarks distributed following the ear canal path and foramina (ovale, spinosum, rotundum, etc.) in the cranial base to obtain spatial relationships. Three-dimensional coordinates were obtained from the landmarks, and the average distance between various landmark pairings was calculated. The repeated measure ANCOVA was used to determine statistical significance. Results In the main data set, the largest mean distance change was found to be 4.37 mm ± 18.29 mm between the left foramen ovale and the left superior medial ear canal opening. The smallest mean distance change was 0.18 mm ± 3.25 mm between the right inferior lateral ear canal opening and the right inferior medial ear canal opening. Conclusions During the adolescent years, the ear canal presents dimensional changes. Even though in different areas throughout the canal, the average distances were minor, still, large standard deviations were present; thus, caution should be taken when trying to use this structure for superimposition of CBCTs.

A Case of Contrast Enhanced Cystic Mass of External Ear Canal Diagnosed as Engorged Hard Tick

A 58-year-old female complained earfullness and otalgia and came to the clinic. Dark gray colored cystic mass obstructing the left ear canal was observed during the endoscopic exam. Contrast enhanced CT image showed an oval shape soft tissue lesion in the mid part of the external auditory canal with a homogenous increased contrast uptake. The mass was removed under microscopic view at outpatient clinic. While dissecting the mass in the ear canal, a pod like structure was visualized. The external organism was densely adherent to the skin and turned out to be an engorged hard tick. Considering the final diagnosis, contrast uptake observed in the CT scan implicates the patient communication of blood between host and parasite. This unique image finding differs from a benign mass lesion in the ear canal was one of the differential diagnosis points for the lesion. This article is reporting the case of tick bite in the ear canal with a rare CT scan finding.

MRI investigation of the ear canal deformation due to earplugs: A first step toward understanding wearing comfort

The effective protection of earplugs is related to the acoustical attenuation but also to the comfort they provide. Earplugs are acoustic seals used to reduce sound transmission in the ear canal. A perfect contact between ear canal and earplug should ideally avoid acoustic leaks leading to under-protection. Practically, this acoustic seal is achieved applying a greater or lesser deformation on the ear canal walls which depends on the earplug insertion and type. However, a too large deformation can modify the acoustic attenuation and cause physical pain due to mechanical pressure exerted onto ear canal walls leading the wearer to take earplugs off and reducing their protection. This study aims at investigating the ear canal deformation of one human subject due to insertion of various earplugs known for providing different levels of protection and different levels of comfort. The shape of the open and occluded right and left ear canals of the subject is measured using MRI technology. The deformation along the ear canal is estimated using an imaging registration method. The results show large displacements at the ear canal entrance for all earplugs and non negligible displacements after the first bend of the ear canal for some of them.