Congenital Bilateral Sensorineural Hearing Loss Research Articles

Abiotrophia defectiva: A rare and lethal but an easy miss!

Abiotrophia defectiva is a nutritionally deficient streptococci, a rare pathogen of infective endocarditis (IE) in children but is frequently known to cause valvular dysfunction and embolic complications. Only nine cases of A. defectiva endocarditis have been reported so far in world literature. We report a case of A. defectiva endocarditis in a 7-year old girl, with a small peri membranous ventricular septal defect with congenital bilateral sensorineural hearing loss status post left-sided cochlear implantation who presented with prolonged fever. A. defectiva should be considered in children with endocarditis with a subacute course and atypical presentations. Although fastidious in growth it is a virulent bacterium preferentially affecting endovascular structures and is implicated in many culture negative endocarditis. Our case reiterates the possibility of a rare cause of this common disease and the challenges encountered while isolating this nutritionally deficient organism and its treatment.

Síndrome de Bartter como causa de atraso no crescimento e de surdez neurossensorial

Bartter syndrome (BS) is a rare renal tubulopathy, which typically becomes apparent during childhood. It is caused by an autosomal recessive inheritance which involves the kidneys’ ability to reabsorb sodium. This report depicts a case of an 18 month-old patient with several manifestations suggesting BS, such as hypokalemia, hypercalciuria, metabolic alkalosis, polyuria, polydipsia, growth delay and congenital bilateral sensorineural hearing loss. The diagnosis was confirmed after a genetic test by classifying the patient as type IV BS. In this context, knowing about BS is crucial to include it in the differential diagnosis of early onset tubulopathies. Therefore, the possible impacts of this condition can be minimized, leading to a better quality of life for the affected.

Deafness-Infertility Syndrome and Auditory Hallucinations

Deafness-Infertility Syndrome and Auditory Hallucinations

Congenital Nonprofound Bilateral Sensorineural Hearing Loss in Children: Comprehensive Characterization of Auditory Function and Hearing Aid Benefit.

A prospective cross-sectional design was used to characterize congenital bilateral sensorineural hearing loss (SNHL). The underlying material of >30,000 consecutively screened newborns comprised 11 subjects with nonprofound, alleged nonsyndromic, SNHL. Comprehensive audiological testing was performed at ≈11 years of age. Results showed symmetrical sigmoid-like median pure-tone thresholds (PTTs) reaching 50–60 dB HL. The congenital SNHL revealed recruitment, increased upward spread of masking, distortion product otoacoustic emission (DPOAE) dependent on PTT (≤60 dB HL), reduced auditory brainstem response (ABR) amplitude, and normal magnetic resonance imaging. Unaided recognition of speech in spatially separate competing speech (SCS) deteriorated with increasing uncomfortable loudness level (UCL), plausibly linked to reduced afferent signals. Most subjects demonstrated hearing aid (HA) benefit in a demanding laboratory listening situation. Questionnaires revealed HA benefit in real-world listening situations. This functional characterization should be important for the outline of clinical guidelines. The distinct relationship between DPOAE and PTT, up to the theoretical limit of cochlear amplification, and the low ABR amplitude remain to be elucidated. The significant relation between UCL and SCS has implications for HA-fitting. The fitting of HAs based on causes, mechanisms, and functional characterization of the SNHL may be an individualized intervention approach and deserves future research.

Hearing loss due to mutations in the genes responsible for Usher syndrome

Usher syndrome is characterized by congenital bilateral sensorineural hearing loss and progressive retinitis pigmentosa, and has an autosomal recessive type of inheritance. The purpose of this work is to summarize the modern data of a clinical picture of Usher syndrome and analyse hearing impairment properties. The frequency of the syndrome among children suffering from hearing loss and deafness is from 3 to 10%. The prevalence of the syndrome in the world is estimated as 4.4 per 100.000 population. The complexity of the diagnosis of the syndrome lies in the significant clinical and genetic heterogeneity. Hearing and vision problems begin at different ages. Primary diagnosis begins with the clinical diagnosis of bilateral hearing loss and visual impairment manifests later. In this case the initial diagnosis of nonsyndromal hearing loss will not be definitive. Molecular genetic studies contribute to the early clinical diagnosis of the syndrome. Understanding the cause of the disease allows to conduct correct medical and genetic counseling and get closer to solving treatment problems.

Keratitis–ichthyosis–deafness (KID) syndrome: Ocular manifestations and management

Keratitis–ichthyosis–deafness (KID) syndrome is a rare hereditary disorder caused by the gene GJB2 encoding connexin 26. Patients present the characteristic clinical triad of congenital bilateral sensorineural hearing loss, keratitis, and ichthyosis. Ocular manifestations are corneal neovascularization and severe Meibomian dysfunction associated with hyperkeratotic lid border. Treatments with ocular lubricants, autologous serum, tetracycline, and anti-inflammatory agents have been described. New therapies such as retinoids, gas-permeable contact lenses, or antiangiogenic agents may be indicated. However, sometimes surgical options such as keratoplasty and keratoprosthesis are needed. We report two cases of KID syndrome with different ocular manifestations and management.

Hearing loss due to mutations or lack of the gene coding protein stereocillin

The description of a clinical picture and audiological features at the hearing loss caused by changes of a STRC gene, coding protein stereocillin (MIM: 606440). Mutations in the numerous genes responsible for the inner ear proteins are the reason for congenital sensorineural hearing loss. The main cause of congenital bilateral sensorineural hearing loss in the Russian Federation are mutations in GJB2 gene it reaches up 68% of cases identified in infancy. GJB2 gene tests already became routine around the world. Possibilities of new methods based on sequencing of new generation (NGS, next generation sequencing) allow to conduct a research of more rare genes connected with a hearing impairment. The most often among GJB2 negative patients reveal mutations and deletion of a gene of STRC. Full audiological examination of 5 children and one adult with a hearing loss from 2 unrelated families is provided. Mutations in STRC gene were identified. All children are examined aged before 8 years, and 3 children failed universal audiological screening in maternity hospital, to two children screening was not carried out as they were born till 2009. The children with the sensorineural hearing loss connected with mutations and deletion of STRC gene failed hearing screening in maternity hospital because of the OAE is not registered, what indicates the congenital nature of a hearing loss. Recently it could not be noticed earlier because of slight increase of hearing thresholds and was regarded only as the early onset. Our data emphasize that the of thresholds from 35 to 60 dB in frequencies 0,5-4 kHz is common for mutations/deletions of STRC gene. The development of molecular genetics methods confirms the hereditary causes of GJB2-negative patients and expands indications for family counseling. Special approach for child with hearing loss so early revealed is necessary and the consultation of parents frightened of screening results is very important.

Comparison of the prevalence and features of inner ear malformations in congenital unilateral and bilateral hearing loss

ObjectivesThe aim of the study was to clarify differences in the prevalence and features of bony malformations in inner ear between congenital unilateral sensorineural hearing loss (USNHL) and congenital bilateral sensorineural hearing loss (BSNHL). MethodsWe conducted a retrospective study of 378 consecutive infants referred from routine newborn hearing screening in the past 18 years. Clinical background, audiological data, and temporal bone computed tomography (CT) findings were analyzed. The prevalence of malformations between USNHL and BSNHL groups were compared using the Chi-square test. ResultsThe proportion of family history of hearing loss was significantly higher in infants with BSNHL than in those with USNHL (26/107 [24.3%] vs. 4/105 [3.7%]; p = 0.0001). Temporal bone CT scanning revealed significantly a higher prevalence of inner ear malformations in infants with USNHL than in those with BSNHL (93/109 [85.3%] vs. 4/107 [3.7%]; p < 0.0001). The most frequent anomaly in USNHL was cochlear nerve canal stenosis (69.7%), followed by cochlear malformations (20.2%), and narrow internal auditory canal (17.4%). Four infants with BSNHL accompanied by inner ear anomaly had complications such as Down's syndrome, developmental delay, or epilepsy. ConclusionsThe prevalence of bony malformations in inner ear and/or IAC was markedly higher in infants with congenital USNHL than in infants with BSNHL. Temporal bone CT scanning may help to clarify the etiology of congenital hearing loss, especially in USNHL.

Surgical anatomy of lateral recess in paediatric auditory brainstem implant patients and its clinical correlates including grades of flocculus.

Auditory brainstem implant (ABI), a standard technique in treatment of profound sensorineural hearing loss in patients with neurofibromatosis 2, is now being increasingly employed in children with congenital bilateral sensorineural hearing loss, as in Michele's deformity. A detailed knowledge of the relevant surgical anatomy of the lateral recess and its anatomical landmarks including the flocculus, the choroid plexus and the root entry zones of facial-vestibulocochlear and glossopharyngeal-vagus nerve complexes and their anatomical variants is mandatory, as it is the conduit for electrode array placement. The placement of electrode may be eased or impeded by these variations. Thirty-two children with congenital bilateral hearing loss underwent surgery through retromastoid suboccipital approach for placement of auditory brainstem implant. The preoperative anatomy was reviewed in detail during procedure and again later in the operative videos. The flocculus was classified into four grades based on its anatomy and relations. Among these, grade II (11 children) was the commonest while grade IV (five children) was least common. Choroid plexus was variable in size across grades of flocculus. Difficulty in defining the anatomy was significantly more (p value = 0.003) in the group with higher grade flocculus (grade III and IV) than in lower grade flocculus (grade I and II). The flocculus in these patients is classifiable into one of the four grades and the surgical nuances such as difficulty in defining the anatomy for placement of ABI are dependent on the characteristics exhibited by the floccular anatomy and relations.

How old is too old for cochlear implantation for congenital bilateral sensorineural hearing loss?

How old is too old for cochlear implantation for congenital bilateral sensorineural hearing loss?

Twenty years of clinical studies of GJB2-linked hearing loss in Russia

The most common cause of congenital hereditary hearing loss was discovered 20 years ago in 1997 when GJB2 gene was revealed in the first locus of recessive hearing loss DFNB1. It encodes protein connexin 26, a structural component of the intercellular channels. Recessive mutations in this gene cause the congenital bilateral sensorineural hearing loss. For many years the aim of our work was to study the prevalence and clinical manifestations of hereditary hearing loss. Our research can be divided into three stages. In the beginning, we investigated the prevalence of GJB2 mutations in a healthy population and in the people suffering from hearing impairment. Further research was conducted in the field of clinical manifestations and evidence of the congenital character of GJB2-related hearing loss. Currently, we are working on the prevalence of mild and moderate hereditary hearing loss and the probability of its progression. Achievements in molecular genetics make it possible to establish the hereditary character of congenital hearing loss and to avoid repeated family cases. Primary prevention of hereditary hearing loss becomes real by raising the awareness of GJB2 mutations carriers.

Ophthalmic pathologies in female subjects with bilateralcongenital sensorineural hearing loss.

The high prevalence of ophthalmologic pathologies in hearing-disabled subjects necessitates early screening of other sensory deficits, especially visual function. The aim of this study is to determine the frequency and clinical characteristics of ophthalmic pathologies in patients with congenital bilateral sensorineural hearing loss (SNHL). This descriptive study is a prospective analysis of 78 young female SNHL subjects who were examined at a tertiary care university hospital with a detailed ophthalmic examination, including electroretinography (ERG) and visual field tests as needed. The mean age was 19.00 ± 1.69 years (range: 15 to 24 years). A total of 39 cases (50%) had at least one ocular pathology. Refractive errors were the leading problem, found in 35 patients (44.9%). Anterior segment examination revealed heterochromia iridis or Waardenburg syndrome in 2 cases (2.56%). Dilated fundus examination revealed retinal pathologies in 15 cases (19.23%), including retinitis pigmentosa or Usher's syndrome in 8 cases (10.25%). Most of the Usher's syndrome cases (87.5%) had consanguinity. Screening for congenital SNHL in the early years of life and routine yearly follow-ups are essential for maximizing the rehabilitation of this disabled group. The high rate of visually debilitating syndromic ocular pathologies associated with high frequency of consanguinity doubles the importance.

A novel insertion-induced frameshift mutation of the SLC26A4 gene in a Korean family with Pendred syndrome

Pendred syndrome (PS) is an autosomal recessive disorder characterized by congenital bilateral sensorineural hearing loss, goiter, and incomplete iodide organification. Patients with PS also have structural anomalies of the inner ear such as enlarged vestibular aqueducts (EVA) and Mondini's malformation. The goiter, which is a major clinical manifestation of PS, usually develops around adolescence. PS is caused by biallelic mutations of the SLC26A4 gene, while nonsyndromic bilateral EVA is associated with zero or one SLC26A4 mutant allele.We report here a Korean family including a young female with PS who had goiter and progressive, fluctuating sensorineural hearing loss that could be partially recovered by oral steroid treatment. Genetic investigation revealed compound heterozygous mutations for p.R677AfsX11, a novel frameshift mutation, and p.H723R in the SLC26A4 gene. Our findings provide detailed information regarding the distribution of mutant alleles for PS and may serve as a foundation for studies to comprehend the genetic portion of syndromic hearing loss.

Diagnostic Evaluations in Pediatric Cases of Congenital Bilateral Sensorineural Deafness

The earliest possible diagnostic evaluation of hearing impairment among infants and children is of the utmost importance for their future well-being. The essential features of the family history and the pediatric physical examination are reviewed, discussed, and illustrated in studies and actual case histories of congenital bilateral sensorineural hearing loss.