Systematic review of the evidence for the etiology of adult sudden sensorineural hearing loss.

OBJECTIVES/HYPOTHESIS: To determine the evidence for different etiologies of sudden sensorineural hearing loss (SSNHL) identified by clinical diagnostic tests in the adult population. STUDY DESIGN: Systematic literature review. METHODS: Review of MEDLINE (1950-October 2009), EMBASE (1980-October 2009), and EBM Review databases in addition to manual reference search of identified papers. Randomized controlled trials, prospective cohort studies, and retrospective reviews of consecutive patients in which a clear definition of SSNHL was stated and data from consecutive patients were reported with respect to etiology of hearing loss. Three researchers independently extracted data regarding patient demographic information, diagnostic tests employed, and the identified presumed etiologies. Discrepancies were resolved by mutual consensus. RESULTS: : Twenty-three articles met the inclusion criteria. The first group of papers searched for different etiologies among patients with SSNHL. Multiple etiologies were identified, including viral infection, vascular impairment, autoimmune disease, inner ear pathology, and central nervous system anomalies. The diagnosis for the majority of patients remained idiopathic. The second group of papers evaluated SSNHL patients with specific diagnostic tests such as autoimmune markers, hemostatic parameters, and diagnostic imaging. CONCLUSIONS: The suspected etiologies for patients suffering sudden sensorineural hearing loss included idiopathic (71.0%), infectious disease (12.8%), otologic disease (4.7%), trauma (4.2%), vascular or hematologic (2.8%), neoplastic (2.3%), and other causes (2.2%). Establishment of a direct causal link between SSNHL and these etiologies remains elusive. Diagnostic imaging is a useful method for identification of temporal bone or intracranial pathology that can present with SSNHL as a primary symptom.

A systematic review of pediatric sensorineural hearing loss in congenital syphilis.

INTRODUCTION: Congenital syphilis is a known cause of progressive sensorineural hearing loss. The prevalence of syphilitic sensorineural hearing loss (SNHL) in childhood is not clearly defined. OBJECTIVE: To determine the frequency and characteristics of pediatric SNHL following intrauterine infection with or exposure to Treponema pallidum in order to develop evidence-based guidelines for audiologic monitoring. DATA SOURCES: Medline (1950-March 2008), EMBASE (1980-March 2008), CINAHL (1982-March 2008), BIOSIS Previews (1969-March 2008), and Cochrane databases. Manual search of references of identified articles and book chapters. STUDY SELECTION: Articles with an inception cohort of children infected with T. pallidum during pregnancy, positive serological identification of syphilis infection in the antenatal period or pathognomonic clinical signs of congenital syphilis infection, and longitudinal serial audiologic evaluations to identify the prevalence and progression of SNHL. DATA EXTRACTION: Patient information, maternal and infant serologic status, and audiometric data extracted in an independent fashion. Discrepancies resolved through mutual consensus. DATA SYNTHESIS: Descriptive statistics. RESULTS: One prospective cohort study met the inclusion criteria. No cases of SNHL in infants with early congenital syphilis treated with antibiotics in the neonatal period were identified. CONCLUSIONS: There have been no reports of children with confirmed congenital SNHL secondary to in utero syphilis infection. Newborns with positive syphilis serology should have hearing screening performed at birth and receive treatment with an appropriate course of penicillin therapy. Longitudinal hearing screening is recommended for all pediatric patients with congenital syphilis, as further studies documenting longitudinal audiometric data for patients previously treated either fully or partly for congenital syphilis are required.

A systematic review of neonatal toxoplasmosis exposure and sensorineural hearing loss.

INTRODUCTION: The Joint Committee on Infant Hearing 2007 Position Statement includes in utero toxoplasmosis infection as a risk indicator for delayed-onset or progressive sensorineural hearing loss. It is recommended that children with congenital toxoplasmosis infection undergo audiologic monitoring to identify congenital and delayed-onset sensorineural hearing loss. OBJECTIVE: To determine the prevalence of sensorineural hearing loss and to develop evidence-based guidelines for audiologic monitoring of children born with congenital toxoplasmosis infection. DATA SOURCES: Systematic search of Medline, EMBASE and Cochrane databases and manual search of references. STUDY SELECTION: Longitudinal studies reporting an inception cohort identified at birth, with serologic confirmation of toxoplasmosis infection, and long-term serial audiometric evaluation. DATA EXTRACTION: Independent extraction of patient and audiometric data. DATA SYNTHESIS: Descriptive statistics. CONCLUSION: The five studies meeting our inclusion criteria report a prevalence of toxoplasmosis-associated hearing loss from 0% to 26%. Improved treatment regimens for toxoplasmosis may account for this range. Three treatment groups were identified and a subgroup analysis of the compiled data was performed. In children receiving limited or no treatment, the prevalence of toxoplasmosis-associated SNHL was found to be 28%. In children prescribed 12 months of antiparasitic treatment but in whom treatment was not confirmed to have started prior to 2.5 months of age and in whom compliance was not ensured, the prevalence of SNHL was 12%. In children treated with 12 months of antiparasitical therapy initiated prior to 2.5 months of age with serologically-confirmed compliance, the prevalence of SNHL was 0%. Only two longitudinal studies were identified and neither reported any cases of delayed-onset or progressive toxoplasmosis-associated SNHL. Children who have received a 12-month course of antiparasitical therapy initiated prior to 2.5 months with serologically-confirmed compliance should have repeat audiometric evaluation at 24-30 months of age. Children with congenital toxoplasmosis that had no treatment, partial treatment, delayed onset of treatment, or compliance issues should undergo annual audiologic monitoring until able to reliably self-report hearing loss.

Natural history of hearing loss in children with enlarged vestibular aqueduct syndrome.

OBJECTIVE: To determine the natural history of hearing loss in children with enlarged vestibular aqueduct (EVA) syndrome. DESIGN: (1) Retrospective cohort study and (2) systematic literature review. SETTING: Tertiary pediatric centre. METHODS: (1) Charts of children assessed by one physician between 1993 and 2000 were reviewed. (2) Source articles were identified by a search of Medline, Embase, and the Cochrane Library of the English-language literature through January 2006, with manual review of references. The search was limited to English, human, and age less than 18 years. MAIN OUTCOME MEASURES: Pure-tone average. Hearing was classified as stable, progressive and fluctuating. RESULTS: (1) Twenty-one children (39 ears) with EVA were identified. Eighty-two percent of ears had stable hearing, and 18% of ears demonstrated progressive hearing loss. (2) Seven source articles were identified and combined with the present data for a total of 310 ears with a mean follow-up of 4 years. Bilateral EVA was found to be six times more common than unilateral EVA, and there was an equal male to female ratio. Stable hearing was found in 67% of ears and progressive hearing loss in 33% of ears. Subgroup analysis demonstrated hearing fluctuations in 50% of progressive hearing loss ears and 34% of stable ears. CONCLUSIONS: Stable hearing is observed in 67% of ears with EVA of which 34% will demonstrate fluctuations in hearing. Progression of hearing loss is seen in 33% of ears of which half will demonstrate fluctuations.

A systematic review of the incidence of sensorineural hearing loss in neonates exposed to Herpes simplex virus (HSV).

OBJECTIVE: To develop evidence-based guidelines for appropriate audiological monitoring of children born following exposure to or infection with Herpes simplex virus (HSV) for development of immediate or delayed-onset of sensorineural hearing loss (SNHL). DATA SOURCES: A Medline search of the 1966-July 2007 database was supplemented by search of the additional database Embase (1980-July 2007). Manual search was conducted of references of identified papers and book chapters. STUDY SELECTION: Articles were sought that were longitudinal in design, to include an inception cohort of children infected with (or exposed to) HSV who were entered at a similar point at birth and followed over time with serial audiometry to identify hearing loss if it developed. DATA EXTRACTION: Patient information and audiometric data extraction from relevant articles was performed independently by all three researchers. Discrepancies were resolved by mutual consensus. DATA SYNTHESIS: Data was analyzed using descriptive statistics. RESULTS: Three papers reported five children with SNHL following apparent disseminated HSV-2 infections in which other obvious clinical sequelae of HSV infection and co-morbid conditions were present. Audiometric information is lacking regarding onset and progression. There are no reports of delayed-onset SNHL following perinatal or asymptomatic HSV infection. CONCLUSIONS: The development of SNHL in children with exposure to HSV occurs rarely. Routine serological screening for HSV infection in otherwise healthy neonates newly diagnosed with SNHL is unjustified. There is insufficient data to define the incidence and natural history of SNHL in children with HSV infections. Carefully designed and conducted studies are needed to address this issue.