Social support buffers against cognitive decline in single mild traumatic brain injury with loss of consciousness: Results from the Canadian Longitudinal Study on Aging.

OBJECTIVES We investigated rates of cognitive decline at three-year follow-up from initial examination in people reporting mild traumatic brain injury (mTBI) with loss of consciousness (LOC) more than a year prior to initial examination. We examined the role of social support as predictors of preserved cognitive function in this sample. METHOD Analyses were conducted on 440 participants who had self-reported LOC of < 1 min, 350 with LOC of 1-20 min, and 10,712 healthy controls, taken from the Canadian Longitudinal Study on Aging (CLSA), a nationwide study on health and aging. RESULTS People who reported at baseline that they had experienced mTBI with LOC of 1-20 min more than a year prior were 60% more likely to have experienced global cognitive decline than controls at three-year follow-up. Cognitive decline was most apparent on measures of executive functioning. Logistic regression identified increased social support as predictors of relatively preserved cognitive function. DISCUSSION mTBI with longer time spent unconscious (i.e., LOC 1-20 min) is associated with greater cognitive decline years after the head injury. Perceived social support, particularly emotional support may help buffer against this cognitive decline.