Nineteen infants with pos themorrhagi c ventricular dilatation were studied with serial auditory brainstem responses at the Department of Paediatrics and Neonatal Medicine, Hammersmith Hospital, London. The cerebrospinal fluid pressure was measured in 9 of the 19 infants directly during lumbar or ventricular taps with a Gaeltic pressure transducer. No correlation was found between cerebrospinal fluid pressure and prolonged interpeak intervals on the BAER. Improvement occurred in 3 patients when cerebrospinal fluid was withdrawn. In one full term infant, improvement in BAER occurred one week after shunting. The lack of correlation between the I-V interpeak interval and the intracranial pressure in preterm infants was probably due to better adaptation of the immature brain to increased intracranial pressure. 
COMMENT. Abnormalities in auditory brainstem responses in premature infants may resolve irrespective of the persistence of progression of ventricular dilatation. Improvements in BAER, especially of the amplitude, could occur after drainage of cerebrospinal fluid in some cases. The responses in full term infants may differ from those of preterm infants.