Long-term effect of head trauma on intellectual abilities: a 16-year outcome study.

Abstract

Intelligence was assessed in a group of 74 people with head injury, 16 years after injury (mean 16.77 years; range 10-32 years), and compared with their performance when assessed at an early stage in recovery (mean 1.05 years). To confirm the presence of long-term impairment relative to estimates of pre-accident ability, to confirm signs of deterioration between early (T1) and late (T2) measures, and to examine relationships between severity of injury, time since injury, length of education, sex and age, and performance on intelligence tests at T2. On the basis of evidence from other studies, a significant difference was expected between estimates of pre-accident intelligence and abilities measured at T1 and T2. Deterioration in performance between T1 and T2, and relationships between demographic variables, severity of injury and intellectual performance were also expected. The data supported long-term intellectual impairment, but there was no deterioration in abilities between T1 and T2. Performance on intelligence tests was associated with years of education but not with other factors.