Social and Behavioral Outcomes following Childhood Traumatic Brain Injury: What Predicts Outcome at 12 Months Post-Insult?

Abstract

This study sought to investigate social and behavioral outcomes 12 months following childhood traumatic brain injury (TBI) and to identify predictors of these outcomes. The study also compared rates of impairment in social and behavioral outcomes at 12 months post-injury between children with TBI and a typically developing (TD) control group. The study comprised 114 children ages 5.5 to 16.0 years, 79 with mild, moderate, or severe TBI and 35 TD children, group-matched for age, sex and socio-economic status. Children with TBI were recruited via consecutive hospital admissions and TD children from the community. Social and behavioral outcomes were measured via parent-rated questionnaires. Analysis of covariance models identified a significant mean difference between the mild and moderate groups for social problems only, but the moderate and severe TBI groups showed a higher rate of impairment, particularly in externalizing problems. Pre-injury function, injury severity, parent mental health, and child self-esteem all contributed significantly to predicting social and behavioral outcomes. Both injury and non-injury factors should be considered when identifying children at risk for long-term difficulties in social and behavioral domains.

Introduction

Following a traumatic brain injury in childhood, social, and behavioral competencies are vulnerable to compromise.^{1

–13} From early seminal research⁴ to more recent findings,^11
–13 studies have indicated difficulties in adaptive skills, internalizing behaviors, and externalizing behaviors post-childhood TBI.

Social and behavioral outcomes

In a systematic review,¹⁴ it was reported that methodological limitations may often hinder the interpretation of findings regarding social outcomes post-childhood TBI. However, they noted that reported impairments have been identified across many domains, including social adjustment, social participation, and social interaction. Difficulties in these domains have further been implicated in quality and maintenance of friendships, relationships, and overall quality of life.^{15

–23} Similarly, more recent systematic reviews^24,25 investigating psychological, psychiatric, and behavioral difficulties following mild TBI also reported that while there was some evidence to support an increased prevalence of these psychosocial outcomes following mild TBI, the literature was insufficient to prove a causal link.

A recent study³ based on the same sample as the current manuscript compared pre-and post-injury measures of social and behavioral outcomes up to 6 months post-injury in children with TBI sustained between 5 and 16 years of age. Findings indicated a higher rate of impairment in these areas among those with TBI, with a significant reduction in social participation from pre-injury levels for those sustaining a more severe injury. Persisting difficulties in social participation have been reported previously in a variety of settings, such as home, school, and community, up to 36 months post-TBI.^{5,6,8,26
–28} Yeates and colleagues⁸ found that childhood TBI resulted in poorer social outcomes when compared with children hospitalized for orthopedic injuries up to 4 years post-injury. At 16 years post-childhood TBI, in young adulthood, survivors performed more poorly on a social perception task when compared with same-age peers,²⁹ suggesting that social cognitive difficulties may underpin more global social deficits.

In the behavioral domain, Taylor and colleagues³⁰ recently reported persistent behavior problems up to 12 months post-injury in children with mild TBI, especially among those with a more complicated mild TBI or younger age at injury. Similarly, others showed that at 10 years post-TBI, behavioral difficulties persist regardless of injury severity.¹¹ Using teacher ratings, behavioral abnormalities in children were described following moderate-to-severe TBI, with externalizing and school-related problems more severe and more frequently observed than internalizing problems.³¹ Mental health problems also have been reported in children with TBI³² and in young adults 16 years post-childhood TBI, where self-report indicated greatest problems for internalizing symptoms such as depression, anxiety, and withdrawal.³³

Predictors of social competence

To understand the wide variation in social outcomes following childhood TBI, a socio-cognitive integration of abilities model (SOCIAL) has been proposed,² which offers an explanation of the underpinnings of social competence (social and behavioral outcomes). The model proposes that social outcomes are influenced by brain development and integrity, external factors (e.g., socio-economic status [SES], parent mental health), and child factors (e.g., pre-injury function, self-esteem). All of these factors—injury severity,^26,34 developmental status,^35,36 and family mental health and SES^37,38—have been linked to social and behavioral outcomes in children with TBI.

With regard to child factors, research has shown that pre-injury social function predicts post-injury social outcome and behavior,³ but less attention has been given to factors such as perceptions of self-worth or self-esteem. In a sample of children up to 5 years post-TBI and ranging from 5–12 years of age at time of assessment, overall lower self-esteem was found, compared with controls and population norms, with the presence of anxiety, depression, and behavior problems predicting this outcome.³⁹ A relationship also was reported between self-esteem and parent behavior, where children with poor self-esteem were characterized as having parents with higher levels of stress. Similar findings were reported in adolescents post-TBI,⁴⁰ with elevated levels of low self-esteem, psychological problems, and adaptive difficulties. Adolescents with TBI and brain lesions were found to have lower self-esteem in relation to perceptions of attractiveness and health. While these researchers^39,40 reported on the importance of self-esteem and its possible links to behavior and mental health outcomes, neither specifically investigated the predictive value of self-esteem for social and behavioral outcomes.

To our knowledge, this is the first longitudinal study to investigate social and behavioral outcomes to 12 months post-TBI while also exploring the contribution of injury characteristics, external factors, and child factors in the prediction of social and behavioral outcomes. The current study has improved upon the methodology of previous studies by: i) inclusion of a clear definition of TBI; ii) inclusion of multiple respondents (child and parent); iii) large sample size, compared with the existing pediatric literature; iv) inclusion of a control group; and v) examination of both traditional and novel predictors of social and behavioral outcomes. Hence, the study aimed to investigate social and behavioral outcomes in children with TBI in comparison with typically developing (TD) children, and to identify predictors of these outcomes at 12 months post-injury. We also sought to compare rates of impairment in social and behavioral outcomes at 12 months post-injury between children post-TBI and a TD control group, as analyses at the group level may mask elevated rates of deficit at the individual level.

We hypothesized that: 1) social and behavioral outcomes at 12 months would be poorer in children with TBI when compared to TD controls; 2) rates of social and behavioral impairment would be greater at 12 months for those with a TBI, compared with TD controls; and 3) social and behavioral outcomes at 12 months would be predicted by injury severity (Glasgow Coma Scale [GCS] score, site of pathology), external factors (SES, 12-month family function and mental health), and child factors (pre-injury social and behavioral status, and 12-month self-esteem).

Methods

This study reports on data from a larger prospective longitudinal study investigating social outcomes post-childhood TBI^1,3 that comprised 114 children ages 5.5 to 16.0 years (79 survivors of TBI and 35 TD children) ascertained between 2007 and 2010. Children with TBI were recruited at time of injury and represented consecutive presentations to the emergency department and intensive care unit at the Royal Children's Hospital, Melbourne, Australia. TD children were recruited from the community through local schools and group-matched for age, sex, and SES.

For the TBI group, inclusion criteria were: i) age between 5.0–16.0 years at injury; ii) documented evidence of closed-head injury and at least two post-concussive symptoms (e.g., headaches, dizziness, nausea, irritability, poor concentration); iii) medical records sufficiently detailed to determine injury severity, including the GCS,⁴¹ neurological, and radiological findings; iv) no documented history of pre-injury neurological or developmental disorder (including learning or attentional disability or autistic spectrum disorder), non-accidental injury, or previous TBI; and v) English speaking. The TD comparison group was required to meet inclusion criteria i), iv) and v) above.

For the TBI group, injury severity was initially classified into four groups (mild: n = 40; mild complicated: n = 11; moderate: n = 19; severe: n = 9). Due to some small cell sizes and following initial subgroup analyses, the groups were collapsed as follows: i) mild (including mild complex, n = 51), with GCS 13-15 on admission, loss of consciousness (LOC) <1 h, skull fracture not requiring surgical intervention; ii) moderate TBI (n = 19), with GCS 9-12 on admission, LOC 1-24 h and/or evidence of intracranial pathology on computed tomography (CT) or magnetic resonance imaging (MRI) scan, skull fracture requiring surgical intervention; and iii) severe TBI (n = 9), wich GCS <9 on admission, LOC >24 h and/or abnormalities on CT or MRI scan. All children with TBI received standard care following their injuries.

Measures

General intelligence

The two-subtest version of the Wechsler Abbreviated Scale of Intelligence⁴² was administered at 6 months post-injury. The Full Scale Intelligence Quotient (mean [M] = 100, standard deviation [SD] = 15) was derived and employed descriptively.

Social and behavioral outcomes at pre-injury (Time 1: T1) and 12 months (Time 2: T2) post-injury

Pre-injury information was collected at recruitment (T1). For children post-TBI, this was based on their function for the 6 months prior to the injury; for TD children, this was based on their functioning at time of recruitment (T1).

Social competence

The Adaptive Behavior Assessment System-II (ABAS-II)⁴³ is a parent-rated questionnaire that examines functional skills necessary for daily living comprising several domains, with the present study focusing on the Social Domain (M = 100, SD = 15). Impairment on the ABAS-II was determined as a score of more than one standard deviation below the test mean (score <85: mild impairment 70-84, severe impairment ≤69).

Social participation

The Child and Adolescent Scale of Participation (CASP)^44,45 is a parent-rated measure of child participation divided into four sections: Home Participation; Community Participation; School Participation; Home and Community Living Activities. It also generates an overall summary score, which was used in analyses. A higher score indicates greater participation, and participants were deemed impaired with an overall participation score equating to “not age expected” (a mean Likert response of 3 or lower).

Child behavior

The Child Behavior Checklist for ages 6–18 (CBCL/6-18)⁴⁶ was completed by parents based on child behavior over the previous 6 months. The respondent rates each of the 113 items as 0 = not true; 1 = somewhat or sometimes true; and 2 = very true or often true). The CBCL provides an Internalizing, Externalizing, Social Problems, and Total Behavior Problem Score (T = 50, SD = 15). For the Total, Externalizing, and Internalizing Scales, a score >60 was considered impaired (mild impairment 61-69; severe impairment 70+); for the Social Problems Scale, >65 was considered impaired (mild impairment 66-69; severe impairment 70+).

Predictors of outcome

Injury characteristics: injury severity

Acute GCS, categorized as mild, moderate and severe as previously described, and lesions were identified and coded according to location (frontal, extra-frontal, subcortical).

The location of neuroanatomical lesions was identified based on visual inspection of MRI by a pediatric neuroradiologist and neuropsychologist with neuroimaging experience. Those involved in the visual inspection where both blind to injury severity status. Once identified, lesions were coded according to location (frontal, extra-frontal, subcortical) using a modification of the Coffey classification system.⁴⁷ This classification system assesses signal abnormality and volume changes as seen on T1, T2, and fluid-attenuated inversion recovery images. Signal change and volume loss were coded in gray and white matter in regions of particular interest of social competence¹: frontal/temporal/parietal/occipital lobes, cerebellum, hippocampus, amygdala, corpus callosum, thalamus, and basal ganglia.

External factors

Socio-economic status

SES (pre-injury only) was determined using the Australian Socioeconomic Index 2006 (AUSEI06)⁴⁸, which translates data coded in accordance with the official occupational classifications of the Australian and New Zealand Standard Classification of Occupations (ANZSCO) into occupational status. Occupational information was provided by the primary caregiver. The AUSEI06 converts scores for ANZSCO major, sub-major, minor, and unit group codes into a continuous scale, ranging from 0 (e.g., laborers) to 100 (e.g., medical practitioners).

Family function

The McMaster Family Assessment Device (FAD)^49,50 is a 60-item questionnaire completed by the parent. It assesses the overall health/pathology of the family. The “General Functioning” scale was used in analyses. Scores range from 1 (“healthy” functioning) to 4 (“unhealthy” functioning), and we generated a dichotomous “healthy/unhealthy” variable, with a score ≥2 considered unhealthy—approximately 2 standard deviations (from a non-clinical sample)⁴⁶ above a score of 1 (healthy).

Parent mental health

The General Health Questionnaire (GHQ-28)⁵¹ screens two major areas: parents' inability to carry out normal functions and appearance of new and distressing phenomena. The total GHQ Score maximum is 28. A total score >4 is suggestive of probable distress.⁴⁷

Child factors

Pre-injury

These include the social and behavioral pre-injury measures as described above.

Self-esteem

The Harter Self Perception Profile for Children (HSPPC)⁵² taps children's perceptions of themselves, both judgment of competence/skills and self-adequacy, and was used as the measure of self-esteem. The HSPPC has six separate subscales: Scholastic Competence, Social Acceptance, Athletic Competence, Physical Appearance, Behavioral Conduct and Global Self-Worth. For the purposes of this study, the focus was on Social Acceptance, Behavioral Conduct, and Global Self Worth because of their relevance to social competence. Each item is scored 1–4, where a score of 1 reflects poor perceived competence and 4 high perceived competence. Impairment is classified as 2SD below the normative mean, where M = 3 and SD = 0.5 (HSPPC⁵²). The reliability of the scale has been reported as satisfactory. Validity was demonstrated through theoretically meaningful correlations with child, parent, and teacher reports of psychopathology and personality.⁵³

Procedure

The study was approved by the Human Research Ethics Committee, Royal Children's Hospital and the Department of Education and Early Childhood Development, Melbourne, Australia. Children with TBI were identified via the emergency department database and intensive care admissions, screened for eligibility, and recruited to the study immediately post-injury. Questionnaires were completed by the primary caregiver at recruitment (Time 1), based on pre-injury status, and then repeated at 12 months post-injury (Time 2). TD controls were ascertained via their schools (Time 1), and followed up 6 months later (Time 2). All families were initially contacted to verify their willingness to participate in the study and then mailed details of the study and requests for written consent. Verbal assent and written consent was sought as per ethics requirements. Participating families were seen on an individual basis by a trained psychologist at an outpatient clinic or at home.

Statistical analysis

Differences between groups across demographic and injury variables were examined using either analysis of variance (ANOVA) for continuous variables or Fisher's exact tests for categorical variables (to accommodate small cell values). Pairwise Bonferroni-adjusted post hoc analyses were conducted following ANOVA models.

To test hypothesis 1, that social and behavioral outcomes would differ for children with TBI and TD children, analysis of covariance (ANCOVA) and subsequent pairwise Bonferroni-adjusted post hoc analyses were conducted. Models included the pre-injury social or behavioral outcome score as a covariate, to adjust for baseline variability.⁵⁴ Effect size partial eta squared (η_p ²) was reported for between-group effects in ANCOVA models; small = 0.01, medium = 0.06, large = 0.13.⁵⁵

For hypothesis 2, that rates of social and behavioral impairment would be greater at 12 months for children with TBI in comparison to TD children, Fisher's exact tests were conducted. In addition, a binary indicator of impairment on any of the social or behavioral outcomes also was tested. Cramér's V was reported as a measure of effect size; small = 0.10, medium = 0.30, large = 0.50 for df = 1; small = 0.06, medium = 0.17, large = 0.29 for df = 3.⁵⁵

For hypothesis 3, to explore predictors of social and behavioral outcome, we extended the ANCOVA model to replicate hierarchical regression analyses, again including T1 outcome scores as covariates. For each regression analysis, Step 1 of the hierarchical model included injury severity in the form of GCS group stratification (mild/moderate/severe), compared with TD controls, and site of pathology (frontal, extra-frontal, and/or subcortical), and the relevant pre-TBI outcome score. Step 2 further included socio-economic status (AUSEI06) and 12-month post-injury family functioning variables (FAD, GHQ) and 12-month self-esteem (HSPPC). As the three outcome measures for self-esteem were correlated (from 0.31 to 0.48), we included Global Self-Worth in the regression analysis to represent a global measure of self-esteem (and avoid multicollinearity).

Due to negative skew and data ceiling for the CASP, ordinary regression (and ANOVA/ANCOVA) models would likely yield biased estimates. As such, the CASP was analysed using Tobit regression models for both hypotheses 1 and 2.⁵⁶ Total effect size R ² was presented for hierarchical regression models (small = 0.02, medium = 0.13, large = 0.26), with the exception of Tobit models (Pseudo R ²). Data for 10 participants too impaired to participate on a specific task were winsorized to a value two standard deviations below the mean.⁵⁷

Results

Demographics

The final sample consisted of 35 controls, and 51 mild, 19 moderate, and nine severe TBI participants. Eighteen of the original 97 TBI participants (11 mild, two moderate, and five severe) and two controls were lost to follow-up at T2. The present sample and those lost to attrition/dropout differed in the proportion of subcortical pathology (p = 0.040) and loss of consciousness (p = 0.015). Those lost to follow-up had more negative outcomes in these injury characteristics, with 10.1% with subcortical lesion in the present sample and 31.3% in those lost, and the present sample reporting a lower rate of LOC (79.8% vs. 59.5%). No other significant differences in demographics and injury severity were found between the present sample and those lost to attrition.

Between-group comparisons (mild, moderate, and severe TBI, and control) in Table 1 showed no significant differences in sex, age at testing, family structure, SES, and time post-injury. The groups also did not differ in family function, parent mental health, child behavior or social problems at T1 or T2. As expected, the groups differed in intellectual ability; however, all groups performed within the average range, and no significant post hoc pairwise Bonferroni-adjusted tests were found. Injury characteristics show expected significant differences for all variables, except age at injury (Table 2).

Table 1.

Between-Group Demographics

	TD Control n = 35		Mild n = 51		Moderate n = 19		Severe n = 9		p^*
Gender, male, n (%)	22	(62.9)	37	(72.5)	11	(57.9)	6	(66.7)	0.623
Age at T2 (years), M (SD)	10.6	(2.9)	11.3	(2.3)	11.8	(2.4)	11.5	(3.2)	0.387
Time post-TBI at T2 (months) M (SD)	-	-	12.8	(1.1)	12.4	(1.0)	12.4	(0.7)	0.216
Socio-economic status (AUSIE06), M (SD)	68.4	(20.0)	57.5	(21.7)	55.9	(26.0)	69.0	(27.3)	0.071
Family structure, n (%)
Intact	29	(82.9)	43	(84.3)	16	(84.2)	7	(77.8)	0.942
Single parent, blended, shared custody	6	(17.1)	8	(15.7)	3	(15.8)	2	(22.2)
T1^#
Family function (FAD), M (SD)	1.5	(0.3)	1.6	(0.3)	1.6	(0.4)	1.7	(0.4)	0.095
Parent mental health (GHQ), M (SD)	2.3	(3.1)	1.2	(3.5)	0.3	(0.8)	0.4	(1.0)	0.078
Child adaptive behavior (ABAS), M (SD)⁺	97.5	(16.4)	98.3	(16.9)	98.5	(13.7)	95.9	(19.5)	0.975
Total behavior problems (CBCL), M (SD)^{^}	45.4	(6.7)	47.4	(11.0)	49.0	(9.9)	52.3	(8.7)	0.220
Social participation (CASP), M (SD)	98.5	(2.8)	98.7	(2.8)	98.8	(4.3)	98.6	(2.3)	0.683
T2^#
Family function (FAD), M (SD)	1.5	(0.4)	1.6	(0.3)	1.7	(0.3)	1.8	(0.2)	0.077
Parent mental health (GHQ), M (SD)	2.0	(3.1)	1.9	(4.8)	0.9	(1.9)	2.0	(3.5)	0.759
Child adaptive behavior (ABAS), M (SD)⁺	104.4	(13.7)	100.8	(16.5)	102.5	(16.3)	98.4	(12.6)	0.636
Total behavior problems (CBCL), M (SD)^{^}	44.9	(7.4)	44.5	(12.0)	49.0	(13.9)	49.1	(14.5)	0.370
Self-esteem (HSPPC Global Self-Worth), M (SD)	3.4	(0.5)	3.5	(0.4)	3.4	(0.5)	3.6	(0.5)	0.695
Social participation (CASP), M (SD)	98.5	(2.8)	98.7	(2.8)	97.0	(6.1)	98.4	(2.4)	0.826
Child IQ (WASI), M (SD)⁺	105.0	(13.3)	100.7	(13.2)	95.5	(15.6)	94.1	(14.6)	0.046

Between-group p value (analysis of variance for continuous variables, Fisher's exact for categorical).

T1: Pre-injury data for TBI group, baseline for control; T2: 12 months post-TBI for TBI group, 6 months post-baseline for control.

Standard score

T-score

TD, typically developing control group; M, mean; SD, standard deviation; AUSEI06, Australian Socioeconomic Index 2006; TBI, traumatic brain injury; FAD, Family Assessment Device; GHQ, General Health Questionnaire; ABAS, Adaptive Behavior Assessment System; CBCL, Child Behavior Checklist; CASP, Child and Adolescent Scale of Participation; HSPPC, Harter Self Perception Profile for Children; WASI, Wechsler Abbreviated Scale of Intelligence.

Table 2.

Between-Group Injury Characteristics

	Control n = 35		Mild n = 51		Moderate n = 19		Severe n = 9		p^*
Age at injury (years) M (SD)	-	-	10.2	(2.3)	10.8	(2.4)	10.5	(3.2)	0.706
Lowest GCS M (SD)	-	-	14.4	(1.1)	11.6	(2.0)	6.1	(2.2)	<0.001
Duration of coma n (%)
None	-	-	26	50.98	5	26.32	1	11.11	0.022
< 5 min	-	-	17	33.33	13	68.42	5	55.56
> 5 min, <24 h	-	-	2	3.92	0	0.00	1	11.11
> 24 h	-	-	0	0.00	0	0.00	1	11.11
Unknown	-	-	6	11.76	1	5.26	1	11.11
Surgical intervention n (%)	-	-	0	0.00	7	36.84	4	44.44	<0.001
Cause of injury n (%)
MVA (passenger, cyclist, pedestrian)	-	-	2	3.92	7	36.84	5	55.56	<0.001
Fall/blow	-	-	49	96.08	12	63.16	4	44.44
MRI scan: site of pathology n (%)
Frontal^	4	9.30	11	21.57	12	63.16	6	66.67	<0.001
Extra-frontal^	1	2.33	8	15.69	7	36.84	3	33.33	0.004
Subcortical	0	0.00	2	3.92	4	21.05	2	22.22	0.004

Between-group p value (analysis of variance for continuous variables, Fisher's exact for categorical).

Controls were asymptomatic.

M, mean; SD, standard deviation; GCS, Glasgow Coma Scale; MVA, motor vehicle accident; MRI, magnetic resonance imaging.

Social and behavioral outcomes

ANCOVA models compared social and behavioral mean outcomes of the TBI groups and TD controls at T2, adjusting for T1 score (Hypotheses 1). Table 3 shows a significant difference between groups in Social Problems (p = 0.028, η_p ² = 0.07). Post hoc Bonferroni comparisons indicate that, after multiple correction, the difference in Mild and Moderate means was statistically significant (adjusted p = 0.023).

Table 3.

ANCOVA Models for Social and Behavioral Outcomes, Adjusting for Pre-Score

		TD Control		Mild		Moderate		Severe
	T^	M	SD	M	SD	M	SD	M	SD	p^*	ES^#
ABAS: Social competence	1	104.40	(13.18)	101.59	(16.12)	101.26	(13.33)	94.78	(17.14)	0.249	0.037
	2	108.77	(11.28)	102.39	(16.28)	106.21	(15.87)	98.56	(14.07)
CASP: Social participation	1	98.49	(2.81)	98.70	(2.79)	98.81	(4.30)	98.57	(2.27)	0.535	0.058
	2	98.38	(2.98)	98.32	(3.97)	95.79	(8.93)	98.19	(2.39)
CBCL: Social problems	1	51.66	(3.18)	53.16	(5.04)	52.89	(5.18)	53.11	(2.71)	0.036	0.075
	2	51.54	(3.25)	52.90	(5.89)	56.47	(11.56)	54.00	(4.97)
CBCL: Internalizing behavior	1	47.03	(8.14)	48.75	(11.37)	45.84	(9.46)	51.11	(9.24)	0.152	0.047
	2	45.97	(9.99)	44.20	(11.09)	47.84	(12.67)	47.67	(12.26)
CBCL: Externalizing behavior	1	46.34	(6.89)	48.78	(10.06)	49.37	(11.74)	54.11	(9.89)	0.687	0.013
	2	45.49	(5.06)	47.67	(10.18)	49.89	(12.94)	52.11	(10.87)
CBCL: Total behavior problems	1	45.43	(6.71)	47.43	(10.96)	49.00	(9.91)	52.33	(8.69)	0.430	0.025
	2	44.86	(7.40)	44.49	(12.01)	49.00	(13.92)	49.11	(14.45)

Between-group p value from ANCOVA model, adjusting for pre-score.

Group effect size η_p ², Pseudo R ² for CASP Tobit models

T1: Pre-injury data for TBI group, baseline for control; T2: 12 months post-TBI for TBI group, 6 months post-baseline for control.

ANCOVA, analysis of covariance; TD, typically developing control group; M, mean; SD, standard deviation; ES, effect size; ABAS, Adaptive Behavior Assessment System; CASP, Child and Adolescent Scale of Participation; CBCL, Child Behavior Checklist.

Rates of impairment

Exact tests investigated rates of social and behavioral impairment between the TBI groups and TD controls at 12 months post-injury (Table 4). Across all measures, rates of impairment were low. Only impairment on the CBCL Externalizing Problems significantly differed between groups, with higher rates of impairment in the moderate and severe TBI groups (21% and 22%, respectively), compared with the mild TBI (15%) and TD control (0%) groups (p = 0.014). Analysis of an “any impairment” (impaired on one or more scales) outcome shows that despite the TD control reporting lower (14%) and severe groups reporting higher (44%) rates of overall impairment, no significant association was found between all four groups (p = 0.366) or between TD controls and combined TBI groups (p = 0.244).

Table 4.

Impairment Fates of Social and Behavioral Outcomes Between Severity Groups at 12 Months

	TD Control n = 35		Mild n = 51		Moderate n = 19		Severe n = 9
	n	(%)	n	(%)	n	(%)	n	(%)	p^1#	ES ^1#	p^2#	ES ^2#
ABAS: Social competence	0	(0.0)	7	(13.2)	1	(5.3)	1	(11.1)	0.080	0.22	0.055	0.20
CASP: Social participation	0	(0.0)	1	(1.9)	1	(5.3)	0	(0.0)	0.525	0.14	1.000	0.09
CBCL: Social problems	0	(0.0)	4	(7.5)	3	(15.8)	0	(0.0)	0.083	0.23	0.098	0.17
CBCL: Internalizing behavior	5	(11.6)	6	(11.3)	4	(21.1)	1	(11.1)	0.800	0.10	1.000	0.01
CBCL: Externalizing behavior	0	(0.0)	8	(15.1)	4	(21.1)	2	(22.2)	0.014	0.26	0.005	0.25
CBCL: Total Behavior problems	2	(4.7)	5	(9.4)	3	(15.8)	3	(33.3)	0.108	0.23	0.388	0.12
Impaired on 1+ scales^*	6	(14.0)	14	(26.4)	5	(26.3)	4	(44.4)	0.366	0.17	0.244	0.13

Impairment on individual ABAS, CBCL, and CASP scales mutually exclusive.

Fisher's exact test p values and effect sizes Cramer's V; ¹between all 4 groups (df = 3), ²traumatic brain injury vs. Control (df = 1).

TD, typically developing control group; ES, effect size; ABAS, Adaptive Behavior Assessment System; CASP, Child and Adolescent Scale of Participation; CBCL, Child Behavior Checklist.

Prediction of outcomes

Predictors of 12-month social and behavioral outcomes in TBI cases were explored using hierarchical regression (Table 5; with Tobit regression used for CASP Total). For all regression models, all blocks of the hierarchical regressions were highly significant (p < 0.01). For each social and behavioral outcome (ABAS, CASP and CBCL Social, Internalizing, Externalizing and Total), the pre-injury score was highly significant in both Blocks 1 and 2 (p < 0.001). The moderate TBI group was significantly different from the TD group in CBCL Social Problems scale (Block 1 p = 0.005, Block 2 p = 0.003), and the mild TBI group in the ABAS model (Block 1 p = 0.035, Block 2 p = 0.039). Moreover, in Block 1, extra-frontal site of pathology was a significant predictor of the ABAS and CBCL Social Problems models.

Table 5.

Hierarchical Linear Regression Models, Predicting Social and Behavioral Outcomes

	ABAS		CASP ^		CBCL: Social		CBCL: Internalizing		CBCL: Externalizing		CBCL: Total
	B	(SE)	B	(SE)	B	(SE)	B	(SE)	B	(SE)	B	(SE)
T1 score^#	0.62^***	(0.07)	1.29^***	(0.33)	0.93^***	(0.11)	0.65^***	(0.09)	0.66^***	(0.07)	0.85^***	(0.08)
Injury severity
TD control	(ref)		(ref)		(ref)		(ref)		(ref)		(ref)
Mild	−5.29^*	(2.48)	−0.76	(2.55)	0.30	(1.11)	−2.33	(2.06)	0.72	(1.64)	−1.83	(1.82)
Moderate	−1.70	(3.62)	−4.67	(3.63)	4.63^**	(1.61)	4.83	(3.00)	2.92	(2.39)	2.25	(2.65)
Severe	−5.07	(4.58)	−2.71	(4.45)	1.87	(2.01)	1.26	(3.75)	1.99	(3.05)	−0.41	(3.34)
Site of pathology
Frontal	0.99	(2.63)	2.09	(2.76)	−1.46	(1.16)	−2.81	(2.17)	−0.17	(1.73)	−2.13	(1.90)
Extra-frontal	6.73^*	(2.98)	0.78	(2.92)	−2.66^*	(1.33)	−2.18	(2.49)	−0.90	(1.97)	−0.22	(2.18)
Subcortical	−8.21	(4.43)	−3.58	(4.41)	3.84	(1.97)	0.01	(3.66)	−0.53	(2.90)	0.18	(3.22)
Step R ²	0.48^***		0.06^**		0.48^***		0.35^***		0.46^***		0.53^***
T1 score^#	0.59^***	(0.07)	1.32^***	(0.34)	0.86^***	(0.11)	0.61^***	(0.09)	0.60^***	(0.08)	0.77^***	(0.08)
Injury severity
TD control	(ref)		(ref)		(ref)		(ref)		(ref)		(ref)
Mild	−5.13^*	(2.45)	−1.16	(2.56)	0.45	(1.12)	−1.74	(2.02)	0.89	(1.65)	−1.28	(1.77)
Moderate	−2.30	(3.59)	−5.87	(3.72)	5.01^**	(1.63)	5.38	(2.99)	3.19	(2.42)	3.22	(2.60)
Severe	−4.71	(4.49)	−1.83	(4.52)	1.54	(2.02)	1.30	(3.67)	2.09	(3.05)	−0.20	(3.25)
Site of pathology
Frontal	2.38	(2.60)	2.92	(2.77)	−2.03	(1.17)	−3.24	(2.14)	−0.72	(1.75)	−3.00	(1.86)
Extra-frontal	5.11	(2.92)	−0.04	(2.95)	−2.04	(1.33)	−0.82	(2.42)	−0.08	(1.96)	1.01	(2.11)
Subcortical	−8.86^*	(4.36)	−3.82	(4.40)	4.11^*	(1.98)	−1.53	(3.59)	−1.07	(2.91)	−0.48	(3.14)
T2 family function (FAD)	−2.55	(3.22)	−2.41	(3.35)	1.57	(1.46)	3.39	(2.68)	3.07	(2.16)	3.42	(2.37)
T2 parent mental health (GHQ)	−0.92^**	(0.27)	−0.37	(0.28)	0.33^**	(0.13)	0.56^*	(0.22)	0.40^*	(0.19)	0.61^**	(0.20)
T2 self-esteem (HSPPC Global Self-Worth)	0.11	(2.25)	−0.70	(2.37)	0.17	(1.03)	−4.22^*	(1.87)	−2.00	(1.52)	−2.67	(1.64)
SES (AUSEI06)	0.01	(0.05)	−0.07	(0.05)	0.01	(0.02)	0.05	(0.04)	0.01	(0.03)	0.04	(0.03)
Step R ²	0.54^***		0.07^**		0.52^***		0.43^***		0.50^***		0.59^***
R ² Change	0.06^*				0.04		0.08^**		0.04		0.06^**

p < 0.05; ^** p < 0.01; ^*** p < 0.001

Step R ² = Pseudo R ² for CASP Tobit models.

T1: Pre-injury data for traumatic brain injury (TBI) group, baseline for control; T2: 12 months post-TBI for TBI group, 6 months post-baseline for control.

ABAS, Adaptive Behavior Assessment System; CASP, Child and Adolescent Scale of Participation; CBCL, Child Behavior Checklist; B, AUTH; SE, standard error; TD, typically developing control group; FAD, Family Assessment Device; GHQ, General Health Questionnaire; HSPPC, Harter Self Perception Profile for Children; SES, socio-economic status; AUSEI06, Australian Socioeconomic Index 2006.

In Block 2, extra-frontal site of pathology no longer predicted ABAS and CBCL Social Problems, replaced by subcortical pathology. Finally, higher self-esteem (HSPPC) was predictive of less CBCL Internalizing problems (p = 0.026), with parental mental health (GHQ) a significant predictor of all outcomes, except the CASP. Significant R ² change results were found in the CBCL Internalizing and Total and ABAS models, driven by the 12-month parent mental health (p = 0.009, p = 0.003, and p = 0.001, respectively). For all other models, distal environmental factors did not further contribute to the models above injury characteristics.

Discussion

This study adds to previous literature in the area of social and behavioral outcomes after childhood TBI by ascertainment of a relatively large sample size and comparison group, inclusion of child and parent informants, longitudinal design, and use of traditional and novel predictors, therefore overcoming limitations in previous research. We first hypothesized that social and behavioral outcomes would be impacted by TBI at 12-months post-injury. Results identified differences only between the mild and moderate TBI groups, but not the severe TBI group, for Social Problems at 12 months post-injury. These findings partially support past research in which injury severity often plays a role in outcome, and where social and behavioral difficulties have been reported post–childhood TBI regardless of injury severity,^6,8,11 but do not support findings of social participation difficulties post-injury.^3,26 It may be that such difficulties had subsided by 12 months, especially as our sample had primarily milder injuries, as there was more attrition in those with more severe injuries. Findings also may be a reflection of the measures used to assess these skill areas, which may not be sensitive to the subtle difficulties evident post-TBI.

Consistent with our expectations, our TBI sample demonstrated higher rates of impairment, compared with TD controls (hypothesis 2), at 12 months post-injury, although only in the Externalizing Behavior domain. Further, those sustaining more severe injuries (moderate and severe) were more likely to exhibit these problems, supporting similar findings observed in a classroom setting.³¹ Investigation of rates of impairment indicated that children with TBI, especially following more severe injury, were more likely to exhibit impairment on one or more outcome domains at 12 months post-injury. These findings support those found in recent systematic reviews^24,25 where the overarching conclusion was that for those sustaining a mild injury, psychological, psychiatric, and behavioral problems resolve following the early recovery phase.

We also hypothesized that social and behavioral outcomes at 12 months would be predicted by pre-injury functioning, severity of injury (GCS, site of pathology), external factors (SES, and 12-month family factors), and child factors (pre-injury child characteristics, 12 month self-esteem). Our findings lend partial support to the hypothesis, where pre-injury status was a significant predictor of outcome, with injury severity significant to a lesser extent. As expected, parent mental health predicted social and behavioral outcome at 12 months, consistent with previous research.^8,37 Unexpectedly, family function and socio-economic status did not predict these outcomes. Perhaps SES is more important in the acute stage rather than longer-term, when more proximal family factors (e.g., cohesiveness) may come into play. The Family Assessment Device (FAD) provides a conceptualization of the family, describing structural and organizational properties and patterns of transaction between members, which had perhaps stabilized by 12 months post-injury and so had a reduced influence on child outcomes. The measure of parent mental health (GHQ) is a screening tool to detect non-psychotic psychiatric disorders that result in an inability to carry out normal functions. The GHQ has a focus on somatic symptoms, anxiety, insomnia, social dysfunction, and severe depression. Therefore, these parental characteristics may be seen over and above the structure and organization in families, as they tap the mental health status of the parent and their ability to be role models and be able to care for and nurture their child following a TBI. Children rely on their parents to guide and nurture them, and if a parent is presenting with mental health issues, then it will interfere with this role and will ultimately have a negative impact on the child. Increased parent stress and mental health problems evident following severe child illness may therefore impact on child outcomes.

A novel contribution of this study is the inclusion of self-reported self-esteem and its association to social and behavioral outcomes. While previous papers have reported the importance of self-esteem with regard to mental health outcomes,^39,40 to our knowledge none have examined self-esteem in relation to social and behavioral difficulties. This study found that lower self-reported self-esteem was predictive of internalizing behavior problems, suggesting that the child's perception of their self-worth plays a role in their behavior and interactions with others. This lends support to previous work^39,40 that argues for an association between self-esteem and the development of psychological problems post–childhood TBI.

Our findings are largely consistent with the SOCIAL model,² in that injury characteristics, external factors (parent mental health), and factors internal to the child (pre-injury status and self-esteem) were found to predict social competence. This highlights the complexities in predicting outcome when pre-injury status, injury severity, family factors, and factors internal to the child all play a role in social competence.

Limitations and future directions

A limitation to this study is the smaller sample size of the severe TBI group, therefore reducing the representativeness of the sample. There also were significant injury (LOC, subcortical pathology) differences between the follow up sample and those lost to follow-up that would impact on generalizability of findings for those with more severe injury. Although correlations between main social and behavioral outcomes were of moderate magnitude (apart from the CBCL Total scale), it should be noted that main outcome models were not adjusted for multiple comparisons so as not to unduly penalize model power. More comprehensive imaging coding was not undertaken; however, this was not the focus of the current study. Further, outcomes were measured via broad-based questionnaires, largely reliant on parent report, which may not be sensitive to the subtle difficulties often experienced by children post-TBI. Parent report of child function also may have been impacted by parent mental health status and so be subject to bias. Self-esteem was measured via self-report, and may be driven by other factors such as limited insight, anxiety, and depression. Due to inconsistent findings regarding predictors of social and behavioral outcomes, future studies are needed to better establish important contributors of short and longer-term outcomes, perhaps with the addition of functional brain connectivity to identify markers of recovery, hence identifying those children that may benefit from early intervention.

Conclusion

At a group level, a significant difference between the mild and moderate TBI groups was found for Social Problems. At 12 months post-injury, impairment rates suggested a continuing impact of TBI on social and behavioral outcomes, with externalizing behaviors presenting as a particular problematic consequence. Significant predictors of social and behavioral outcomes at 12 months post-injury included pre-injury child characteristics, injury severity, external and child factors. The findings have important clinical implications, indicating factors that may identify children at risk for social and behavioral difficulties post-TBI, while highlighting the complexity involved in predicting individual outcomes. Longer-term studies are essential in order to gain further understanding of the complex interplay between childhood TBI, internal factors, and external factors so that intervention may provided for those at risk before further consequences are evident in adolescence and adulthood.

Footnotes

Acknowledgments

The Victorian Neurotrauma Initiative funded this research, and it also was supported by the Victorian Government Operational Infrastructure Scheme.

Author Disclosure Statement

No competing financial interests exist.

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