[Clinical and electrophysiological investigations of hearing in neonates. I. Behavioral audiometry and auditory brainstem response in evaluation of the auditory apparatus in pre- and full-term neonates].

Auditory Brain stem Responses (ABRs) and behavioural thresholds were studied in 130 neonates born between 25 to 42 weeks of gestational age. ABR thresholds were determined by the weakest stimulus that elicited a recognizable and replicable wave V. Behavioural audiometric thresholds for 1 and 2 kHz pure tones were determined by taking the lowest of threshold for eliciting auro-palpebral reflex. In 130 tested neonates ABR responses were normal in 102 (78.5%) while 28 babies (21.5%) elicited a pathological response. In the normal ABR group mean thresholds values ranged between 24.7-35 dBHL, and it was observed that the thresholds diminished with neonatal maturation. Behavioural audiometry disclosed that 77.5% normal full-term neonates responded to pure tone 1000 Hz, with mean threshold of 92.83 dBHL, while only 59.09% of pre-term neonates responded to pure tone stimuli at 101 dBHL.