title: A systematic review of neonatal toxoplasmosis exposure and sensorineural hearing loss.
abstract: BACKGROUND
  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.
  
  
  METHODS
  Systematic search of Medline, EMBASE and Cochrane databases and manual search of references.
  
  
  METHODS
  Longitudinal studies reporting an inception cohort identified at birth, with serologic confirmation of toxoplasmosis infection, and long-term serial audiometric evaluation.
  
  
  METHODS
  Independent extraction of patient and audiometric data.
  
  
  RESULTS
  Descriptive statistics.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Division of Pediatric Otolaryngology, BC Children's Hospital, Department of Surgery, University of British Columbia, Vancouver, BC, Canada.
authors.forename: Erik D
authors.initials: ED
authors.lastname: Brown
authors.forename: Justin K
authors.initials: JK
authors.lastname: Chau
authors.forename: Shahnaz
authors.initials: S
authors.lastname: Atashband
authors.forename: Brian D
authors.initials: BD
authors.lastname: Westerberg
authors.forename: Frederick K
authors.initials: FK
authors.lastname: Kozak
mesh_terms: D000977:Antiparasitic Agents / Q000627:therapeutic use; D001301:Audiometry, Pure-Tone; D006319:Hearing Loss, Sensorineural / Q000175:diagnosis / Q000453:epidemiology*; D006801:Humans; D007231:Infant, Newborn; D015997:Neonatal Screening / Q000379:methods*; D015995:Prevalence; D012720:Severity of Illness Index; D014123:Toxoplasmosis / Q000188:drug therapy / Q000453:epidemiology*
chemical_list: D000977:Antiparasitic Agents