title: Incidence and pattern of hearing impairment in children with ≤ 800 g birthweight in British Columbia, Canada.
abstract: OBJECTIVE
  This study aimed to evaluate changes over time in the characteristics of permanent hearing impairment (HI) in extremely low-birthweight (ELBW ≤800 g) children.
  
  
  METHODS
  Data from sequential visits up to 5 years of age assessing hearing and other neurodevelopmental outcomes were extracted from a cohort of ELBW subjects born between 1983 and 2006 at a single Canadian site. Trends in HI incidence, severity and association with other impairments were analysed in three 8-year epochs.
  
  
  RESULTS
  Fifty of 586 ELBW children had a HI. HI rates increased from 5% in epoch 1 to 7% in epoch 2-13% in epoch 3 (p = 0.01). Mild HI decreased from 78% in epoch 1 to 35% in epoch 3 (p = 0.03). Median age at diagnosis decreased from 13 to 8 months. Comorbidities were more common in HI children than non-HI children: cerebral palsy (40% vs 14%, p < 0.0001)), cognitive (38% vs 12%, p < 0.0001) and visual impairments (16% vs 6%, p = 0.009).
  
  
  CONCLUSIONS
  The incidence and severity of hearing impairment in a cohort of extremely low-birthweight children increased significantly from 5% to 13% (p = 0.01) over a 24-year period. Comorbidities were common. Potentially modifiable causes are explored.
authors.affiliation: Department of Pediatrics, University of British Columbia, Vancouver, Canada. asynnes@cw.bc.ca
authors.forename: Anne R
authors.initials: AR
authors.lastname: Synnes
authors.forename: Shelagh
authors.initials: S
authors.lastname: Anson
authors.forename: Julia
authors.initials: J
authors.lastname: Baum
authors.forename: Laurie
authors.initials: L
authors.lastname: Usher
mesh_terms: D000367:Age Factors; D001955:British Columbia / Q000453:epidemiology; D002675:Child, Preschool; D002658:Developmental Disabilities / Q000453:epidemiology*; D005500:Follow-Up Studies; D034381:Hearing Loss / Q000453:epidemiology*; D006801:Humans; D015994:Incidence; D007223:Infant; D052577:Infant, Extremely Low Birth Weight; D007231:Infant, Newborn; D012307:Risk Factors; D012720:Severity of Illness Index