DETECTABILITY OF COCHLEAR, ACOUSTIC NERVE AND BRAIN-STEM POTENTIALS IN A GROUP OF NORMAL PRETERM NEWBORNS RECORDED WITH INSERT EARPHONE

Thirty-four 'normal' preterm newborns were tested at 40 weeks postconc eptional age. To separate electromagnetic artifacts from cochlear pote ntials and subsequent auditory brainstem responses, a test was given u sing an insert earphone at 90, 70, 50, 30 dB nHL. The detectability of receptor potentials, waves I, III, V, as a function of stimulus inten sity is described; at 90 dB nHL exclusively, we could always identify these peaks because of the better morphological distinctiveness of eac h potential. When trying to evaluate the acoustic pathway in premature newborns, we suggest that brainstem response audiometry should be per formed at 90 dB nHL with an insert earphone.