THE CLICK-EVOKED OTOACOUSTIC EMISSION, C-EOAE, IN PRETERM-BORN INFANTS IN THE POST CONCEPTIONAL AGE RANGE BETWEEN 30 AND 68 WEEKS

Click-evoked otoacoustic emissions (cEOAEs) were repeatedly recorded i n an operational sample of 144 very low birth weight (VLBW) infants. A subgroup of 22 was composed of all those babies in which at least 4 r ecordings were successfully done. The mean birth weight of this group was 1040 g, and the mean duration of assisted ventilation was 17 days. The OAE-recordings were done in the post conceptional age (PCA) range between 30 and 68 weeks. In relation to ear function screening it was shown that the EOAE was present in 95% of the ears at least once at a ny age, while it was present in all recordings in only 34%. From a lon gitudinal analysis of the recordings per infant it appeared that: (1) the OAE recorded was already present in one infant at the PCA of 29.4 weeks; (2) in most infants the level of the OAE varies strongly betwee n recordings; (3) in each infant the OAE-level shows an increase with age, on average this growth amounts to 10 dB between the PCAs of 31 an d 42 weeks; (4) there is no clearcut difference in the growth of high- and low-frequency components of the EOAE.