Military and Veterans Affairs
Higher childhood socioeconomic status (SES) is associated with higher intelligence scores as well as better cognitive recovery following pediatric traumatic brain injury (TBI). Less is known about the effects of childhood SES on long-term cognitive outcome following TBI acquired in adulthood. We examined the association between childhood SES and general intelligence throughout adulthood in a sample of 240 Vietnam veterans from diverse socioeconomic backgrounds. 186 of the study participants sustained a penetrating brain injury (pTBI) in their 20s, providing the largest study testing childhood SES effects on recovery of cognitive function following non-pediatric TBI. General intelligence was measured pre injury (upon enlistment in the military), and then again 15, 35, and 42 years post injury. For both participants with and without pTBI, childhood SES was a significant predictor of intelligence scores 42 years post-injury, however it was not associated with the rate of cognitive change. Moreover, childhood SES predicted cognitive outcome among patients with left hemisphere damage better than it did for right hemisphere damage patients. These findings provide the first evidence indicating the persistent effects of childhood SES on cognitive functioning later in adulthood following a TBI. Childhood SES should be considered when predicting and assessing cognitive recovery following TBI, even when the injury occurred in adulthood.
Objective : To examine the association between childhood socioeconomic status and the level and rate of change in intelligence scores throughout adulthood following traumatic brain injury.
Design: This longitudinal study included data collected for the Vietnam Head Injury Study between 1960s and 2012 (follow-up, 5-22 years). Assessment of intelligence score was done by observers blind to patient’ childhood SES.
Setting: Outpatient multidisciplinary reevaluation of brain-injured veterans and controls.
Participants: 186 combat male veterans with a penetrating brain injury and 54 male veterans without a brain injury volunteered to participate in this study. The groups were matched on age, childhood SES and pre-injury intelligence.
Interventions: Not applicable.
Main Outcome Measure(s): Childhood SES was determined for each participant based on parental educational attainment and occupational prestige. General intelligence was initially assessed pre-injury upon induction into the military, and again 15, 35 and 42 years post-injury. Total brain volume loss and lesion laterality were determined based on CT scans.
Results : For both participants with and without TBI, childhood SES accounted for a significant portion of the variance in intelligence scores pre-injury and in all three post-injury evaluations, however, it was not associated with the rate of cognitive change. Moreover, childhood SES predicted cognitive outcome among patients with left hemisphere damage better than it did for right hemisphere damage patients.
Conclusions : These findings provide the first evidence indicating the persistent effects of childhood SES on intelligence scores later in adulthood following a TBI. Childhood SES should be considered when predicting and assessing cognitive recovery following TBI, even when the injury occurred in adulthood.