| This dissertation examined the relationships between different levels of neonatal risk, cognitive development and inhibitory control in three-year-old children. The assignment of subjects to clinical groups was determined by neonatal neurofunctional status, based on auditory brainstem evoked responses (BAER), and neonatal neurostructural status, based on cranial ultrasound (US) data. The sample included 87 children and was comprised of five groups: 35 fullterm controls (the FTN/N group), 20 infants from the Neonatal Intensive Care Unit with normal BAER and normal US (the NICU/N group), 13 infants with only BAER abnormality (the BAER-only group), 14 infants with mild or moderate IVH seen on US (the Mild/Mod group), and eight infants with severe structural damage seen on US (the Severe group).;The subjects were tested with the Griffiths Mental Development Scales and two tasks that were designed to tap inhibitory control (IC): a rapid sequential automated naming task and a graphomotor task. The results indicated that: (1) differential cognitive development and IC outcomes resulted from different types and magnitude of neonatal insult, (2) males were more likely than females to be in clinical groups the BAER-only and the Severe group that had more cognitive developmental deficiencies and IC difficulties than did other groups, (3) females were more likely than males to be in clinical groups, the NICU/N and the Mild/Mod groups, that showed minimal residual deficits, (4) the NICU/N group showed general cognitive development within the normal range, minimally slowed processing, and discrete deficiencies in tasks requiring motor integration, (5) the Mild/Mod group showed general cognitive development resembling that of the FTN/N group, no IC difficulties, but some minimally slowed processing and discrete but moderate difficulty in tasks requiring eye-hand coordination, (6) the Severe group showed multiple cognitive deficiencies, slowed processing and more IC difficulties than any other group, (7) performance of the BAER-only group resembled most that of the Severe group, though with a lesser magnitude of deficits; their cognitive performance was marked by difficulties in a number of domains and minimal slowed processing. In addition, IC difficulty, on both the verbal and the graphomotor task, was found independent of speech ability, coordination or the ability to perform under time pressure.;This study indicates that brainstem malfunction intrudes upon the development of a number of cognitive functions and the development of IC. |
