Hearing Impairment in Very Low Birth Weight Infants Incidence, Risks Factors Analysis and Follow Up

Abstract

Premature infants, especially those with very low birth weights (VLBW), have a high risk of developing hearing impairment. Early diagnosis and treatment of hearing problems plays an important role in speech development and academic and occupational performance later in life. The purpose of this study was to evaluate the incidence and risk factors of hearing impairment in VLBW infants and their associated developmental outcome subsequent to early diagnosis followed by early treatment. From January 1998 through to July 2003, 215 VLBW infants (M:F=113:102) were enrolled. Potential risk factors for hearing impairment were recorded. All infants underwent assessment of brainstem auditory evoked potential (BAEP) at a corrected age of 6 months. If an abnormal test result (＞40 decibels dB) was noted, additional testing was done at the corrected ages of 9, 12, 18, and 24 months. In this study, we found significant associations between hearing impairment and birth body weight, gestational age, duration of mechanical ventilator usage, duration of hospitalization, respiratory distress syndrome, surfactant treatment, bronchopulmonary dysplasia, periventricular leucomalacia, cerebral palsy, necrotizing enterocolitis and sepsis but there was no significant relationship with Vancomycin and gentamycin use. Two hundred and eight (96.7%) of the 215 infants passed the initial auditory test. Of the seven (3.3%) with abnormal hearing test results, one had a mixed type hearing impairment, one had a severe bilateral peripheral type and the others had mild peripheral type of impairment. All of these infants were provided with hearing aids immediately after diagnosis and no associated speech commencement delay was noted. We conclude that high risk infants must be assessed early for hearing impairment.