Factors associated with auditory neuropathy/dys-synchrony in a developing country

Abstract

Two-stage hearing screening, with a first stage of automated otoacoustic emissions (AOAE) followed by automated auditory brainstem response (AABR), is the protocol of choice for the early detection of congenital and early-onset hearing loss (PCEHL) in a number of developed countries. However, this protocol would miss children with auditory neuropathy/auditory dys-synchrony (AN/AD). The aim of the study was to ascertain the characteristics of infants with AN/AD profile in a developing country and identify predictors of this condition in a primary care, non-hospital-based setting. Case-control analysis of the sociodemographic and medical profile of 11 infants with normal outer hair cell function, but confirmed with PCEHL, were compared to 64 infants with normal hair cell function and no PCEHL. The infants with AN/AD profile were further compared with 45 infants with PCEHL who failed transient evoked otoacoustic emissions (TEOAE). Independent predictors were determined from univariate and multiple logistic regression analyses. Factors associated with AN/AD profile in the univariate analysis were male sex (OR, 9.39: 95% CI 1.14−77.74) and hyperbilirubinaemia requiring exchange blood transfusion (OR, 5.63: CI 1.06–129.85). About 64% of the infants with AN/AD profile had a history of hyperbilirubinaemia and 54.5% were hospitalized in the first month of life for a serious illness. No independent factor was predictive of AN/AD from multiple logistic regression analysis. Infants with AN/AD profile were significantly more likely to have a history of hyperbilirubinaemia (OR, 14.00: CI 3.00−165.34) and be hospitalized in the first month of life (OR, 7.80: CI 1.80−33.77) than infants with PCEHL who failed TEOAE. There is no prognostic/selective tool for the early detection of infants with AN/AD profile in non-hospital-based settings in developing countries. AABR screening of infants with normal outer hair cells, who have a history of hyperbilirubinaemia with or without exchange blood transfusion, is recommended as far as practicable, where a two-stage TEOAE/AABR protocol is implemented.

• infant hearing screening
• early-onset hearing loss
• risk factors
• neonatal jaundice