The findings indicate that the family environment accounts for significant variance in psychosocial outcomes following TBI in young children. The family environment was an independent predictor of behavioral adjustment and social competence across groups, but not of adaptive functioning (i.e., CBCL and PKBS/HCSBS, but not ABAS). More specifically, better family functioning predicted better behavioral adjustment at 18 months post-injury, authoritative parenting predicted better social competence across time, and permissive parenting predicted worse social competence across time; and these relationships held true for both children with TBI and those with OI. Consistent with previous research (Anderson et al., 2006
; Catroppa et al., 2008
), the results provide support for the notion that the family environment is an important predictor of young children’s functioning after TBI, and must be considered along with injury-related variables in predicting psychosocial outcomes.
Even more critically, the findings are consistent with our hypothesis that the family environment is a significant moderator of the impact of TBI. The family environment moderated group differences in behavioral adjustment and adaptive functioning, but not in social competence (i.e., CBCL and ABAS, but not PKBS/HCSBS). More specifically, parenting style moderated behavioral adjustment, with more pronounced effects of TBI seen among children whose parents reported higher levels of permissive and authoritarian parenting; and the quality of the home environment moderated adaptive functioning, with more pronounced group differences tending to be seen among children from lower quality homes. These findings extend existing research, which has not specifically examined the moderating influence of the family environment on the outcomes of young children with TBI. Given the low probability of detecting interactions in non-experimental research designs (McClelland & Judd, 1993
), the presence of multiple significant interactions, all of which were of a similar nature, argues strongly for the existence of a complex interplay between the damaged brain and its environmental context during recovery from TBI in young children.
Notably, the moderating effect of the family environment varied as a function of multiple factors, including injury severity, time post injury, the specific dimension of the environment under consideration, and the type of outcome assessed (Taylor & Alden, 1997
). With regard to injury severity, the moderating effects of the family environment were most consistent for children with complicated mild to moderate TBI, whose psychosocial function worsened over time in the context of more permissive and authoritarian parenting and lower quality home environments. In contrast, the moderating role of the family environment actually appeared to wane across time for children with severe TBI, who consistently showed deficits in psychosocial functioning by 18 months post-injury regardless of the family environment, despite early variability in outcomes attributable to the family environment. In a previous study of children sustaining TBI in later childhood, the moderating effects of the family environment were most apparent for those with severe TBI (Taylor et al., 2002
; Yeates et al., 1997
). The contrast between these findings suggest that children who sustain severe TBI at a young age may be less able to overcome the deleterious effects of those injuries than older children, even in the context of a supportive family environment. In contrast, young children with less severe TBI may be more likely to offset the effects of their injuries in a supportive environment, but are vulnerable to deleterious effects in less positive environments.
The moderating role of the family environment also varied as a function of time since injury. For instance, high levels of authoritarian parenting were associated with better behavioral adjustment at 6 months post injury, but with worse adjustment at 18 months. This result suggests that authoritarian parenting may suppress behavior problems initially following TBI in young children, but is not effective and may actually exacerbate problems over the longer term. More broadly, the finding suggests that the moderating influence of the family environment can change over time, presumably depending on the status of children’s recovery from TBI and corresponding changes in how environmental contingencies help shape their behavior.
The role of the family environment also may vary according to the specific dimension of the environment being considered. In the current study, parenting and the quality of the home environment were more consistently related to psychosocial outcomes than was global family functioning. This may reflect a stronger influence of parenting style and the quality of the home environment than of family functioning on children’s psychosocial development (Gottfried & Gottfried, 1984
). Another possibility is that the influence of family functioning is largely indirect, and actually mediated by its impact on parenting and the stimulation offered by the home environment. Statistical analyses of complex causal models would be needed to differentiate among these competing explanations.
With regard to outcome measures, injury severity helps account for both cognitive and behavioral outcomes in this sample, but the family environment is more closely related to the behavioral outcomes assessed in this study than to the cognitive outcomes reported previously (Taylor et al., 2008
). Family risk factors also have been found to exacerbate the psychosocial outcomes associated with prematurity and very low birth weight (Breslau, 1995
), but are less predictive of other developmental outcomes (Bendersky & Lewis, 1994
; Hack et al., 1992
). A possible explanation for these related findings is that cognitive functioning in young children depends primarily upon the integrity of the central nervous system following a neurological insult like TBI, and hence is less affected by the family environment. In contrast, psychosocial outcomes are likely to depend not only on the integrity of the central nervous system, but also on the many environmental influences on behavior. Future research is needed that expands on the current findings by investigating more discrete psychosocial outcomes than the broad-based measures examined in this study.
Although the focus of this study was the moderating influence of the family environment on psychosocial outcomes following TBI in young children, we should acknowledge that children who suffer traumatic injuries not involving the brain may also be vulnerable to psychosocial difficulties. Moreover, the degree to which they are at risk may be related to the severity or nature of their injuries (Stancin et al., 2001
). In the current study, very few of the children with orthopedic injuries suffered severe injuries requiring multiple surgeries or resulting in disfigurement or significant physical disability. However, such children are probably at more risk of psychosocial difficulties, and their outcomes may also be moderated by the family environment in a manner akin to that shown in the current study to characterize children with TBI.
The current study is characterized by several shortcomings. First, analyses were constrained to an examination of linear change post-injury because of the limited number of time points at which outcome data were collected. Future studies should involve data collection at more than three time points, to increase the reliability with which linear change is estimated as well as to permit modeling of non-linear change. Measurement issues are also a potential concern in the current study. The ratings of parenting style and family functioning were provided by parents, who also completed ratings of psychosocial outcomes. Thus, shared rater variance may have inflated the correlations found between those predictors and outcomes; however, this should not have confounded the assessment of the moderating effects of the family environment, as long as the inflation due to shared rater variance was similar for both the TBI and OI groups. Another measurement limitation was the use of different test versions for children of different ages. On all three measures of psychosocial functioning, some children were rated using the preschool version of the test while others were rated using the school-aged version. Test version was included as a covariate in data analyses, thereby controlling for consistently higher ratings on the preschool version of all three measures. However, we cannot be certain whether differences in test versions had inadvertent effects on group comparisons.
Another weakness is that the family environment was only measured once, shortly after the injury. An alternative explanation for the apparent decline in the moderating influence of the family environment among the severe TBI group is that the family environments of children with severe TBI may be more subject to change as a consequence of the injury, and thus the early post-injury family environment may become less predictive with time for those children. Future studies are needed to explore the potentially bidirectional relationships over time between the family environment and children’s psychosocial outcomes (Taylor et al., 2001
). A related concern is that the study also did not take into account the potential influences of educational, rehabilitative, and other treatment services. A significant proportion of children with TBI received services outside the home, and such services could have influenced both family functioning and children’s psychosocial outcomes, potentially reducing the impact of the pre-and early post-injury family environment, perhaps especially in the severe TBI group. Attempting to assess the impact of these services is fraught with difficulty, because their provision is inevitably confounded with injury severity in the context of a naturalistic study. However, we acknowledge that they could affect the relationship between the pre- and early post-injury family environment and children’s subsequent psychosocial outcomes.
Despite these weaknesses, the results of the current study have important clinical implications. They suggest that rehabilitation programs should devote resources not only to the child who has suffered a TBI, but also to the child’s family. To the extent that the family environment is related to psychosocial outcomes, and actually moderate the effects of TBI, rehabilitative interventions should involve efforts to assess parenting skills and home environments, identify families that are at risk, and foster more effective parenting and the provision of developmentally-appropriate stimulation at home. We have previously shown in this sample that TBI results in a disruption of reciprocity in parent-child interactions, so that the usual positive benefits of warm, responsive parenting are less apparent for young children with TBI (Wade et al., 2008
). Recent studies with parents of children with very low birth weight have shown that these parenting behaviors can be increased through intervention resulting in improved cognitive development (Smith, Landry, & Swank, 2005
). These findings suggest that parenting interventions could be adapted to improve developmental outcomes following TBI in young children (Wade, Oberjohn, Burkhardt, & Greenberg, in press