NEUROLOGIC MATURATION AND AUDITORY EVOKED RESPONSES IN LOW BIRTH WEIGHT INFANTS

Abstract

The maturation of the nervous system of two groups of infants of low birth weight was estimated by the results of a standardized clinical neurologic examination and by evaluation of the electroencephalographic responses to auditory stimuli (clicks). Algebraically summed responses to clicks were recorded simultaneously from 10 scalp electrodes, using a standard electroencephalograph, tape recorder, and a computer of average transients. The results obtained by the two methods were compared with the age postconception, estimated from the maternal history. One group consisted of infants whose birth weights were below the 10th percentile for their gestational age (37.1 ± 2.0 weeks); the other group consisted of infants whose birth weights were similar to the first group but were between the 25th and 75th percentile for their gestational age (31.0 ± 2.3 weeks). In the small-for-age infants, the electroencephalographic responses and the neurologic reflexes were more mature than in the infants of similar birth weights who were not small for age. The results of both examination methods correlated well with the estimated postconception age but less well with birth weight, postnatal age, or somatic growth.