Defi nitions
Traumatic brain injury severity was measured
using the lowest presenting emergency
department pediatric Glasgow Coma Scale
(GCS) score.27 Traumatic brain injury was
categorized by severity: mTBI was defi ned
as a GCS score greater than or equal to 13
upon presentation to health care, with a GCS
score of 15 at discharge or after 24 hours if
hospitalized; 1 or more focal signs including
a period of transient confusion, loss of
consciousness for 30 minutes or less, and/
or transient neurological abnormalities.28,29
Mild TBI was subclassifi ed as complicated
mild based on computed tomography evidence
of intracranial hemorrhage. Moderate
TBI and sTBI were categorized by a GCS
score of 9 to 12 and 3 to 8, respectively. Intubated
and sedated children were scored 3T.
The comparison group included children
with an upper or lower extremity long bone
fracture without TBI who were recruited
contemporaneously with the TBI group.
Orthopedic injury comparisons isolated the
outcomes of TBI from those of the injury
alone. Trauma registrars assigned the Abbreviated
Injury Scale.30
Parents completed surveys in English or
Spanish of family demographic information,
family functioning, social support, and
child outcome measures a median of 8 days
(interquartile range, 3-15 days) after injury
to represent preinjury values. Follow-up assessments
were collected at 3, 12, 24, and 36
months in person, online, or by telephone.
Trained study coordinators abstracted medical
records for clinical and injury mechanism
data using standardized forms.
Discussion
Our study of EF growth curves during the
fi rst 3 years after TBI found diff ering patterns
of children’s recovery depending on injury
severity, age, and the EF subscale assessed.
Consistent with prior literature, there was
stepwise worsening of scores for children
with mTBI, cmmTBI, and sTBI compared with
controls with OI.18,19,23,24 Across outcomes,
trajectories varied over time for TBI groups;
however, children worsened most sharply
from baseline to 12 months. Some subgroups,
particularly sTBI, showed a secondary acceleration
between 24 and 36 months. Children
with all severities of TBI did not fully recover
to their preinjury level of functioning.
Recovery patterns diff ered by EF subscale
and injury group. After cmmTBI and
sTBI, Inhibit scores worsened until 24 months
and then plateaued. This contrasts with the
Emotional Control and Working Memory
subscales, which showed improvement after
24 months for children with cmmTBI but an
increase in problems for sTBI between 24 and
36 months. Plan-Organize scores steadily
worsened over the 3-year period. Children
with mTBI had persisting parent-reported
decrements 3 years after injury in all subscales
except Inhibit. Because mTBI is common,
even small persisting decrements are
important at the population level.
We hypothesized that age at injury and
sex would moderate the eff ect of TBI on EF
outcomes. Age × time interactions indicated
that Inhibit scores increased over time for
children aged 2 to 11 years but decelerated
for adolescents. This fi nding is consistent
with prior studies that (1) reported greater
inhibition defi cits in infants and preschoolers
than in older children14 and (2) noted
relative sparing in late childhood compared
with early childhood and adolescence.17,22
Plan-Organize scores were initially lower in
children aged 2 to 5 years and accelerated
across follow-up at a faster rate than in older
children and adolescents. Adolescents were
not selectively vulnerable to EF worsening.
Our fi nding of vulnerability of specifi c EF in
preschoolers that increased over time should
be examined in relation to an uninjured comparison
group.
Sex diff erences in the development of
some EFs vary by age in cross-sectional
studies36 but have not been described longitudinally.
Age at injury interacted with sex for
the Inhibit, Working Memory, and Emotional
Control subscales.17,19,22 Scores diff ered by
sex within age groups at baseline, and although
these initial diff erences translated to
outcomes at 36 months, patterns of recovery
between boys and girls were similar. Future
confi rmatory studies of sex-specifi c recovery
patterns with these and other outcomes are
needed.
26 | DALLAS MEDICAL JOURNAL • March 2022
Children with good EF development are
more likely to succeed in school, home, and
social settings than those with EF diffi culties.
37-39 Similar to other studies, our BRIEF
mean scores for children with TBI were within
population norms. However, trajectories of
children with TBI diverged from the OI group,
indicating small to larger eff ect sizes, and did
not return to their preinjury levels. Protective
factors in this study included good family
function and high social capital, suggesting
that a family-centered approach promotes
children’s long-term success. Across the TBI
severity spectrum, children’s development
of EF should be monitored; as some EFs may
worsen again after a plateau, targeted assessment
may identify the need for cognitive
or socioemotional supports.
Limitations
This study has some limitations. All assessments
were by parent report, which measures
refl ecting behaviors associated with
EF in everyday settings. However, ratings are
subjective, which may lead to underreporting
or overreporting in all groups. Ecologic
and direct EF tests correlate poorly, making
it diffi cult to know whether they measure the
same construct, a recognized problem with
EF measurement overall.40 Children participating
in the follow-up had overall better
family function, potentially biasing our study
toward better outcomes. Diff erences in patterns
between Spanish and English speakers
on some subscales require further study.
Conclusions
This cohort study assessed the recovery
of children’s EF after experiencing mild-tosevere
TBI. Study results suggest that children
with all severities of TBI have EF decrements
as long as 3 years after injury, with some
experiencing a secondary increase in EF
scores after an initial plateau. Results further
suggest that children with TBI may struggle
over time as tasks become more complex,
leading to a need for reassessment and different
supports to improve participation in
the school, home, and community. DMJ
To read the research in its entirety, including all data analysis and results, you can fi nd it on the JAMA Open Network.
A full list of references featured in this article can be found online in the full text.
SUPPLEMENTS:
eTable 1. Description of Cohort by Follow Up Status
eTable 2. BRIEF Outcome Models
eTable 3. BRIEF Outcomes, TBI vs Orthopedic Injury Group, Preinjury to 36 Months
eTable 4. Eff ect of Preinjury Family Characteristics on BRIEF Outcomes
eFigure 1. Cohort Flow Diagram
eFigure 2. BRIEF Emotional Control Outcomes Over Time by Injury Group and Age (Spanish Language Preference)
eFigure 3. BRIEF Inhibit Outcomes Over Time by Injury Group and Age (Spanish Language Preference)
eFigure 4. BRIEF Memory Working Outcomes Over Time by Injury Group and Age (Spanish Language Preference)
eFigure 5. BRIEF Plan-Organize Outcomes Over Time by Injury Group and Age (Spanish Language Preference)