Influence of APOE polymorphism on cognitive and behavioural outcome in moderate and severe traumatic brain injury

To analyse the influence of apolipoprotein (APOE) epsilon4 status on the cognitive and behavioural functions usually impaired after moderate and severe traumatic brain injury (TBI).

In all, 77 patients with TBI selected from 140 consecutive admissions were genotyped for APOE. Each patient was subjected to neuropsychological and neurobehavioural assessment at least 6 months after injury.

Performance of participants carrying the epsilon4 allele was notably worse on verbal memory (Auditory Verbal Learning Test), motor speed, fine motor coordination, visual scanning, attention and mental flexibility (Grooved Pegboard, Symbol Digit Modalities Test and part B of the Trail Making Test) and showed considerably more neurobehavioural disturbances (Neurobehavioral Rating Scale-Revised) than the group without the epsilon4 allele.

In particular, performance on neuropsychological tasks that are presumed to be related to temporal lobe, frontal lobe and white matter integrity is worse in patients with the APOE epsilon4 allele than in those without it. More neurobehavioural disturbances are observed in APOE epsilon4 carriers than in APOE epsilon2 and epsilon3 carriers.