Accelerated postnatal neural conduction in the caudal brainstem in very premature infants born small-for-gestation.

Abstract

This study investigated postnatal brainstem conduction in very premature infants born small-for-gestation (SGA) and explored postnatal changes in the altered brainstem conduction at term as these infants grow. The maximum length sequence brainstem auditory evoked responses (MLS BAER) were studied at four months after term in very premature infants with SGA. The data were compared with those without SGA (non-SGA). The SGA infants manifested significantly shorter I-III interval and significantly greater III-V/I-III interval ratio at higher rates of 227-910/s clicks, compared to non-SGA infants (all p < 0.05). There were small differences in other MLS BAER measures between the two groups, which were not statistically significant. The slope of I-III interval-rate function in SGA infants was moderately smaller than in non-SGA infants. These differences between SGA and non-SGA infants were smaller than those previously detected at term. Postnatal neural conduction in very premature SGA infants is accelerated in caudal brainstem regions, with no appreciable abnormality in rostral brainstem regions. The distinctly altered brainstem auditory conduction detected at term in these infants was mitigated during postnatal development, underscoring a positive trajectory in postnatal neurodevelopment in SGA infants but there remains moderate abnormality four months after term. Very premature SGA infants manifested significantly shorter I-III interval in MLS BAER at four months after term. Postnatal neural conduction in SGA is accelerated in caudal brainstem regions, with no appreciable abnormality in rostral brainstem regions. The distinct alteration in brainstem auditory conduction detected at term has mitigated during postnatal development. The differential effects of SGA on neural conduction in caudal and rostral brainstem regions at term have been alleviated with increasing age. These findings underscore a positive trajectory in postnatal neurodevelopment of in SGA but there remains moderate abnormality at four months after term.