Kelley M. Dodson

Etiology of unilateral hearing loss in a national hereditary deafness repository

PURPOSE The aim of this study was to characterize the genetic, audiologic, and epidemiologic characteristics of unilateral hearing loss (HL) in a national hereditary deafness repository. MATERIALS AND METHODS This is a prospective clinical study involving 34 subjects identified in a national hereditary deafness repository. Clinical data and family history of HL were obtained on enrollment. Candidate deafness genes were screened by single-stranded conformation polymorphism, and mutations were confirmed with sequencing. RESULTS Thirty-four subjects (19 males, 15 females) with unilateral HL were identified, ranging in age from 2 months to 36 years. The mean age at diagnosis was 7 years, and the left ear was affected in 62% of the cases. The racial distribution of our sample was 62% white, 23% African American, and 15% Hispanic. Imaging results were available in 47%, and most (69%) were considered normal. Nineteen percent had enlarged vestibular aqueducts, 2 had ipsilateral Mondini dysplasia, and 1 had a common cavity deformity. Twenty subjects (59%) had a family history of HL, with 26% specifically reporting familial unilateral HL. Mutational screening revealed sequence variants in the GJB2 (connexin 26), GJB3 (connexin 31), TECTA, and COCH genes. Two novel mutations were detected in COCH and TECTA. CONCLUSIONS Sequence variants in known deafness genes were detected in more than one-third of our study population, suggesting that gene/gene or gene/environmental interactions may indeed play a role in the etiology of some cases of unilateral deafness. Further prospective studies including congenital cytomegalovirus screening at birth and molecular screening of deafness genes in children with congenital unilateral HL will be required to establish the etiology of unilateral deafness with certainty.

Rosai Dorfman disease presenting as synchronous nasal and intracranial masses

A 56-year-old woman with vertex headaches, new-onset seizure disorder, nasal obstruction, and hyposmia was found to have a dural-based intracranial mass as well as bilateral masses arising from the inferior turbinates and extending into the nasopharynx. The patient underwent endoscopic resection of the involved portions of the inferior turbinates, including the sizable nasopharyngeal component. Craniotomy was performed at a later date. Both pathologic specimens were consistent with extranodal Rosai-Dorfman disease. The patient showed resolution of all symptoms after surgery. Rosai-Dorfman disease, or sinus histiocytosis with massive lymphadenopathy, is a rare entity usually presenting as cervical nodal disease. When extranodal disease of the head and neck is present, prompt recognition and conservative surgical management is the treatment of choice for this benign pseudolymphomatous entity.

Vestibular Dysfunction in DFNB1 deafness

Mutations of GJB2 and GJB6 (connexin‐26 and 30) at the DFNB1 locus are the most common cause of autosomal recessive, nonsyndromic deafness. Despite their widespread expression throughout the vestibular system, vestibular dysfunction has not been widely recognized as a commonly associated clinical feature. The observations of vertigo accompanying DFNB1 deafness in several large families prompted our hypothesis that vestibular dysfunction may be an integral, but often overlooked, component of DFNB1 deafness. Our aim was to define the prevalence of vestibular dysfunction in Cases of DFNB1 deafness and Controls with other forms of deafness. We developed and used a survey to assess symptoms of vestibular dysfunction, medical, and family history was distributed to Cases with deafness due to pathogenic GJB2 and/or GJB6 mutations and deaf Controls without DFNB1 deafness. Our results showed: Surveys were returned by 235/515 Cases (46%) with DFNB1 mutations and 121/321 Controls (38%) without these mutations. The mean age of Cases (41) was younger than Controls (51; P < 0.001). Vestibular dysfunction was reported by 127 (54%) of Cases and was present at significantly higher rates in Cases than in deaf Controls without DFNB1 deafness (P < 0.03). Most (63%) had to lie down in order for vertigo to subside, and 48% reported that vertigo interfered with activities of daily living. Vertigo was reported by significantly more Cases with truncating than non‐truncating mutations and was also associated with a family history of dizziness. We conclude that vestibular dysfunction appears to be more common in DFNB1 deafness than previously recognized and affects activities of daily living in many patients.

Middle ear fluid characteristics in pediatric otitis media with effusion

OBJECTIVE Persistent otitis media with effusion is caused by poor clearance of middle ear fluid usually following an episode of acute otitis media. This fluid is thought to be viscous and poorly transportable by cilia. Because a subset of children require multiple myringotomy and tube placements for recurrent disease, we hypothesized that children requiring repeated procedures would have effusion fluid that was more viscous and less transportable than those having their first procedure. DESIGN Prospective clinical study. SETTING Tertiary care center. PATIENTS AND INTERVENTIONS Middle ear secretions were collected at the time of myringotomy and tube insertion in 36 children accrued sequentially. Twenty-six of these children were having their first procedure and 10 had previously undergone myringotomy and tube placement. MAIN OUTCOME MEASURES The secretions were evaluated for in vitro mucociliary transportability, and dynamic rheology in a magnetic microrheometer. RESULTS Children with the need for repeated procedures had effusions with lower mucociliary transportability, and overall higher mean measures of surface mechanical impedance/frictional adhesion, but these did not reach statistical significance. Mucopurulent effusions had significantly greater transportability than both the mucoid and serous effusions in both groups. CONCLUSIONS Persistent or recurrent otitis media with effusion is associated with poorly transportable middle ear fluid, which may have higher frictional adhesion. The best mucociliary transportability was measured in mucopurulent effusions.

Superficial siderosis: A potentially important cause of genetic as well as non‐genetic deafness

Superficial siderosis is an important disease that is increasingly being recognized as a cause of sensorineural hearing loss. Hemosiderin, resulting from repeated episodes of subarachnoid bleeding, is deposited preferentially on the surface of the eighth nerve, cerebellum, and brain stem as a consequence of glial catabolism of ferritin within those structures. This deposition eventually results in destruction and demyelination within the central nervous system, leading to the cardinal clinical findings of superficial siderosis: hearing loss, ataxia, and myelopathy. This mechanism may contribute to the pathogenesis of several forms of genetic deafness, and should be considered as a diagnostic possibility in cases of late onset deafness even in the absence of an overt history of subarachnoid bleeding.

The Clinical and Audiologic Features of Hearing Loss Due to Mitochondrial Mutations

Objectives To characterize mitochondrial sequence variants present in a nationwide hereditary deafness DNA repository of samples from deaf subjects and to define the clinical presentation and audiometric characteristics of individuals with a mitochondrial sequence variant. Study Design Retrospective review of results for select mitochondrial mutations performed on DNA samples from subjects compiled from 1997 to 2009. Setting National hereditary deafness DNA repository. Subjects and Methods Available samples from subjects in the repository were screened to identify those with mitochondrial sequence variants. Clinical data on the nature of mutation, type and severity of the hearing loss, and sex, age at diagnosis, family history of hearing loss, and ethnicity were analyzed. Results Eighty-six patients were identified with mitochondrial mutations or 3.5% of the subjects studied. Among those with mitochondrial mutations, 21 (24.4%) had the m.7445A>G substitution, 18 (20.9%) had the m.1555A>G substitution, 18 (20.9%) had the m.961T>G substitution, and 29 (33.7%) had a m.961delT+C(n) complex deletion. The majority of patients had bilateral severe to profound hearing loss. Fifty-three (62%) patients were female, and a family history of hearing loss was documented in 66 (76.7%) patients. The deafness was recognized prior to 3 years of age in 26 patients. Conclusion Mitochondrial deafness in this sample was associated with a variety of genetic mutations and a wide spectrum of clinical presentations. Because of increased aminoglycoside susceptibility associated with some forms of mitochondrial deafness, matrilineal relatives may be at risk in those cases, highlighting the importance of making an accurate diagnosis prior to exposure.

Familial unilateral deafness and delayed endolymphatic hydrops.

Delayed endolymphatic hydrops (DEH) is a unique disorder characterized by fluctuating otologic symptoms in the setting of preexisting unilateral deafness. The symptoms include aural fullness, fluctuating hearing, and/or episodes of vertigo similar to those observed in Meniere disease and may occur ipsilateral or contralateral to the previously deafened ear. In most reported cases, the unilateral deafness has been a profound sensorineural hearing loss with a sudden onset that has been variously attributed to bacterial or viral labyrinthitis, acoustic or cranial trauma, otosclerosis, and congenital CMV infection. Familial occurrence of the syndrome has not previously been reported in the literature. In this report, we describe two possible familial instances of delayed DEH. These patients raise the possibility that genetic factors may sometimes be the cause of this unusual syndrome.

Attainment of surgical competence in otolaryngology training

Our aim was to determine the postgraduate year (PGY) of residency at which residents achieve competence in key otolaryngologic procedures as perceived by residents and program directors (PDs), determine resident or programmatic factors affecting PGY at which residents perceive attainment of competence, and evaluate the relationship between resident and PD perceptions for attainment of competence in these procedures.

Risk Factors Associated With Unilateral Hearing Loss

OBJECTIVE To analyze the presence of Joint Committee on Infant Hearing (JCIH) risk factors and co-occurring birth defects (CBDs) in children with unilateral hearing loss (UHL). DESIGN Retrospective review. SETTING Statewide registry of universal newborn hearing screen data for all children born in Virginia from 2002 through 2008. PATIENTS The study population comprised 371 children with confirmed UHL. MAIN OUTCOME MEASURES Universal newborn hearing screen status, presence or absence of JCIH risk factors, and CBDs RESULTS Of the 371 children with confirmed unilateral hearing loss, 362 (97.5%) were identified through a failed universal newborn hearing screen. Of these 362 children, 252 (69.6%) had no JCIH risk factors and 110 (30.3%) had 1 or more risk factor reported. Nine children (2.5%) with 1 or more risk factors passed the universal newborn hearing screen but had later-onset UHL. Craniofacial anomaly was the most commonly reported JCIH risk factor in 48 children (43.6%). A family history of permanent childhood hearing loss was present in 24 children (21.8%). Twenty children (18.2%) had stigmata associated with a syndrome including hearing loss. Of the 110 children with UHL and a JCIH risk factor, additional CBDs were identified in 83 (75.5%). An ear-specific anomaly was most prevalent in 37 infants (44.6%), followed by cardiovascular anomalies in 34 infants (41.0%). CONCLUSIONS Thirty percent of children with confirmed UHL had a JCIH risk factor, most commonly craniofacial anomalies, family history of hearing loss, and stigmata of syndromes associated with hearing loss. However, the absence of JCIH risk factors does not preclude the development of UHL. Further studies assessing the etiology of UHL and risk factor associations are warranted.

Genetics of hearing loss: focus on DFNA2

The purpose of this review is to assess the current literature on deafness nonsyndromic autosomal dominant 2 (DFNA2) hearing loss and the mutations linked to this disorder. Hearing impairment, particularly nonsyndromic hearing loss, affects multiple families across the world. After the identification of the DFNA2 locus on chromosome 1p34, multiple pathogenic mutations in two genes (GJB3 and KCNQ4) have been reported. The overwhelming majority of pathogenic mutations linked to this form of nonsyndromic hearing loss have been identified in the KCNQ4 gene encoding a voltage-gated potassium channel. It is believed that KCNQ4 channels are present in outer hair cells and possibly inner hair cells and the central auditory pathway. This form of hearing loss is both phenotypically and genetically heterogeneous and there are still DFNA2 pedigrees that have not been associated with changes in either GJB3 or KCNQ4, suggesting that a possible third gene exists at this locus. Further studies of the DFNA2 locus will lead to a better understanding of progressive hearing loss and provide a better means of early detection and treatment.