Survivors
of childhood traumatic brain injury (TBI) often suffer negative
long-term outcomes, including attention problems and cognitive deficits.
Although severity of TBI is a major factor influencing outcomes,
premorbid functioning also influences outcomes. Poor premorbid functioning
appears to exacerbate the effects of TBI, whereas good premorbid
functioning helps to buffer the effects of TBI. This moderating
effect of premorbid functioning was tested by Yeates et al. (2005),
who compared 4-year outcomes for 41 children who suffered severe
TBI, 41 children who suffered moderate TBI, and 50 children who
suffered orthopedic injury (OI), all of whom were between 6 and
12 years old at the time of injury. Premorbid functioning was assessed
by administering the CBCL a week after the child's injury. Severity
of TBI was assessed using the Glasgow Coma Scale (GCS; Teasdale
& Jennett, 1974). Four years post-injury, children in the severe
TBI group had significantly higher scores on both the CBCL Attention
Problems syndrome and the ADHD-IV Rating Scale (DuPaul, Power, Anastopolous,
& Reid, 1998) than children in the moderate TBI and OI groups.
In the severe TBI group, premorbid CBCL Attention Problems scores
significantly moderated the effects of TBI on long-term attention
problems, as measured by both the CBCL and the ADHD Rating Scale.
For both the CBCL and the ADHD Rating Scale, hierarchical linear
regression indicated that higher premorbid Attention Problems scores
amplified the long-term risk for children with severe TBI compared
to children with OI. This moderating effect was not found when comparing
the moderate TBI group with the OI group. Clinically significant
scores on the CBCL Attention Problems syndrome (T > 60) were
obtained by 46% of the severe TBI group versus 26% of the OI group.
This difference was magnified for children with clinically significant
premorbid Attention Problems (82% for severe TBI vs. 42% for OI)
but was attenuated for children with low premorbid Attention Problems
scores (32% for severe TBI vs. 21% for OI). Children with severe
TBI also obtained significantly lower scores than children with
OI on several cognitive measures tapping auditory working memory,
verbal fluency, verbal rule learning, cognitive flexibility, response
speed, and focused attention. Performance on all the cognitive tests
was significantly associated with long-term CBCL Attention Problems
scores in all groups, but premorbid Attention Problems scores did
not moderate the effects of TBI on cognitive outcomes. The authors
concluded that their findings illustrate the construct of reserve
capacity, whereby the greater the level of premorbid problems indicated
by CBCL Attention Problems scores, the greater the impact of severe
TBI on long-term attentional difficulties.
Reference:
Yeates,
K.O., Armstrong, K., Janusz, J., Taylor, H.G., Wade, S., Stancin,
T., et al. (2005). Long-term Attention Problems in Children with
Traumatic Brain Injury. Journal of the American Academy of Child
and Adolescent Psychiatry, 44, 574-584.