Neuropsychological outcome was evaluated in a prospective,
longitudinal follow-up study of children age 4 months to
7 years at injury with either mild-to-moderate (N
= 35) or severe (N = 44) traumatic brain injury
(TBI). Age-appropriate tests were administered at baseline,
6 months, 12 months, and 24 months after the injury. Performance
was compared on (1) composite IQ and motor, (2) receptive
and expressive language, and (3) Verbal and Perceptual–Performance
IQ scores. In comparison to mild-to-moderate TBI, severe
TBI in infants and preschoolers produced deficits in all
areas. Interactions between task and severity of injury
were obtained. Motor scores were lower than IQ scores,
particularly after severe TBI. Both receptive and expressive
scores were reduced following severe TBI. Expressive language
scores were lower than receptive language scores for children
sustaining mild-to-moderate TBI. While severe TBI lowered
both Verbal and Perceptual– Performance IQ scores,
Verbal IQ scores were significantly lower than Perceptual–Performance
IQ scores after mild-to-moderate TBI. Mild injuries may
produce subtle linguistic changes adversely impacting estimates
of Verbal IQ and expressive language. Within the limited
age range evaluated within this study, age at injury was
unrelated to test scores: The impact of TBI was comparable
in children ages 4 to 41 months versus 42 to 72
months at the time of injury. All neuropsychological scores
improved significantly from baseline to the 6-month follow-up.
However, no further change in scores was observed from
6 to 24 months after the injury. The persistent deficits
and lack of catch-up over time suggest a reduction in the
rate of acquisition of new skills after severe TBI. Methodological
issues in longitudinal studies of young children were discussed.
(JINS, 1997, 3, 581–591.)