MORBIDITY RELATED TO AGE AT TIME OF INJURY
Since children have a better rate of survival after TBI, it is often assumed that pediatric outcomes are more favorable than adult outcomes. This is often attributed to the plasticity theory, suggesting that the young brain has a better opportunity to recover function. As noted in the pathophysiology section, however, injury to the developing brain may affect response to injury and the ability for future development and learning to occur. Also, the pediatric brain has had less time to learn skills and overlearn skills. A recent publication confirms that young age at the time of injury does not have a neuroprotective effect and that the mechanism of improvement after injury may differ between those injured as children and those injured as adults (273).
TBI during infancy has been shown to result in difficulty developing expressive and receptive language skills. Infants sustain a higher proportion of TBI that is secondary to nonaccidental trauma and their outcomes are poor. Koskiniemi (274) reported the long-term outcome of TBI in children and identified that the worst outcomes typically occurred in those children who were younger than 4 years of age. That study demonstrated similar results to a study done by Kriel (65) in which 97 pediatric patients who were unconscious for greater than 24 hours were followed, with the worst outcomes seen in children who were younger than 6 years of age and involved both cognitive and motor impairment. However, significant functional improvement has been noted in children who have participated in rehabilitation programs after nonaccidental trauma (275).
Older children show fairly good recovery of language function and independent ambulation. This was evaluated in a study of 28 adolescents followed longitudinally after brain injury. Twenty-five of them recovered language function, and 21 of them recovered independent ambulation. However, they had a lower high school graduation rate and employment rate than an age-referenced population. Their social interactions are impaired, as two-thirds of these individuals reported that after their TBI, their social life declined, and in fact, only 1 of the 28 subjects was married at the time of the follow-up, compared with 61% of the reference population (64).
LONG-TERM OUTCOMES
Anderson and colleagues (276) published a prospective longitudinal study of a group of 40 children with TBI at ages 2 to 7 that they compared to a group of 16 healthy controls acutely and at 12- and 30-month follow-up as well as at 10 years postinjury. MRI scans were obtained for the TBI subjects at 10-year follow-up. As anticipated, those with severe TBI had the poorest outcomes and the greatest deficits in the cognitive domain, particularly in adaptive, executive, and social abilities. Younger age was linked to lower white matter volume at 10 years, but it was unrelated to functional outcomes. As noted in previous studies, family function predicted social and behavioral outcomes and preinjury adaptive function was predictive of 10-year adaptive abilities. The authors concluded that this data supported that recovery is poorer with injury to the very young and that the immature brain does not result in an increased likelihood of recovery.
Another report about attention problems after TBI included the 40 children noted previously. Those with severe TBI had continuing concerns with attention, both those that develop early and later developing skills. Again, a comparison group of 19 noninjured controls was included. Factors that contributed to attention at 10 years after injury included age at injury and acute IQ (277).
Crowe and colleagues (278) reported on the outcomes of accidental TBI in 53 children injured prior to age 3 and assessed an average of 40 months after injury. They were compared to a group of 27 children without injury. Children with moderate and severe TBI (grouped together) had significantly lower IQ scores than the control group (although still within the average range) but no differences were seen on parent behavior ratings. No group differences were seen for processing speed as measured by coding on the Wechsler Preschool and Primary School Intelligence Scale—Third Edition coding subtest. Consistent with previous research, predictors of long-term intellectual, behavioral, and social function after early TBI were socioeconomic status, family function, and parental mental health.
Rivera and colleagues (279) reported on disability seen at 3,12, and 24 months after TBI in children and adolescents in a large prospective cohort study that included children younger than 18 years at the time of TBI and a comparison group with an arm injury. Outcome measures included health-related quality of life, adaptive skills, and participation. The cause of injury varied with the severity of injury (falls—mild 56.6%, moderate 34.1%, and severe 23.1%; motor vehicle occupant most common cause in the moderate and severe TBI groups.) At 3-, 12-, and 24-month follow-ups, children in the moderate and severe TBI groups had PedsQL, Adaptive Behavior Assessment System—Second Edition and Child and Adolescent Scale of Participation scores that were significantly lower than baseline, and at 24 months lower than the comparison group as well.
Another study looking at quality of life noted that it was the time postinjury, not the severity of injury, that correlated with quality of life findings and that these were still significant up to 5 years after injury (280).
Ganesalingam and colleagues (281) reported executive function and social competence in young children 6 months after TBI. Children were aged 3 years 0 months to 6 years 11 months when injured. A control group included children hospitalized with orthopedic injury. They concluded that poorer performance on neuropsychological tests of complex executive functions after severe TBI might be related to impairments that indicate poor self-regulation, metacognition, and effortful control. Higher levels of behavioral aspects of executive functions were related to higher levels of social competence. Individuals with moderate TBI did not perform differently than the control group for social competence.
Sullivan and Riccio (282) published a review of language functioning and deficits following pediatric TBI in 2010. They concluded that language deficits experienced by children post-TBI are quite variable and that comparison of outcomes is complicated by the lack of standard assessments or categorization of TBI. They also noted the lack of information about the interventions used to address language deficits.
PREVENTION
Prevention campaigns against child abuse and shaken impact syndrome have largely been educational campaigns provided by perinatal hospital staff and pediatricians.
Seatbelt use has been shown to reduce fatalities by 45% in passenger cars and by 60% in light trucks. Child safety seats, like seatbelts, decrease injury and death in the pediatric population when correctly installed. Their use has been associated with a reduction in mortality by 70% for infants and by 47% to 54% for toddlers. Seatbelt use in children decreased the need for hospitalization by 69% (2). Helmet use during motorized vehicle use has been documented to decrease the number of hospital-treated head injuries and the severity of motorcycle-related TBI (283).
Aggressive injury prevention campaigns, such as the "ThinkFirst" National Injury Prevention Foundation program, aim to educate children on the effects of brain injury related to gun accidents and sporting accidents, as well as the benefits of seatbelt use and general safety (244). The use of bicycle helmets has reduced the frequency and severity of brain injuries (284-287). Greenwald (2) reported bicycle helmet use decreased the risk of serious brain injury by up to 85%. Rule changes and better equipment in football have significantly reduced severe neurologic injuries (30,258). Efforts should be made to prevent mild brain injuries by avoiding risky behavior, wearing helmets when appropriate, following sports rules, and training properly. Following these guidelines can minimize the incidence and long-term consequences of concussions. Furthermore, in sporting activities, as previously discussed, guidelines for returning to play should be followed to avoid multiple concussive events and worsening cumulative effects.
Other prevention strategies to reduce TBI include lowering the height of playground equipment to no higher than 5 feet and fabricating play surfaces on the playground out of rubber, sand, or wood chips for better absorption of impact in the event of a fall (2). Finally, prevention of pediatric TBI begins with adults modeling safe behaviors within the home. Whenever adults are around children, safety-conscious behaviors should be demonstrated, including regular and routine safety belt use and helmet use during sporting activities.
LONG-TERM REHABILITATION FOLLOW-UP
The role of the pediatric physiatrist in caring for the child with TBI continues throughout the child's development. Cognitive deficits may not actually be evident in the very young child until higher cognitive skills are expected to develop. Follow-up should continue throughout the child's development, with the need for intervention intermittently re-evaluated by the patienf s physiatrist, therapists, and school team.
PEARLS AND PERILS
1. Injury at a younger age (younger than 4-6 years) typically results in poorer outcomes. This is perhaps due to increased vulnerability of the young child's brain to injury and the injury's impact on development.
2. Following a concussion, the injured brain cells are vulnerable to repeat injuries, which can cause extensive neuronal loss. For this reason, the brain should be rested following the concussion until all symptoms have resolved.
3. The long-term outcomes in motor, cognitive, and behavioral function may be better in focal injuries versus diffuse injuries, given the isolated nature of the brain damage.
4. Context-sensitive rehabilitation, with integration across many domains of functioning, and providers using the team approach should be practiced.
5. Care needs to be taken to distinguish cerebral atrophy (hydrocephalus ex vacuo) from posttraumatic hydrocephalus.
6. In children, seizures early after injury do not correlate with late seizures.
7. Long-term anticonvulsant prophylaxis has not been shown to decrease the development of late seizures.
8. Children often perform better in an evaluation setting than in their daily life.
9. It is important to be able to distinguish among DI, SIADH, and cerebral salt wasting.
