Memory loss after brain injury worse when E4 form of Alzheimer's gene present

A gene implicated in Alzheimer?s disease makes it harder for the brain to recover memory functions after brain injury, according to a new study by researchers at the University of South Florida and the Veteran?s Administration Defense and Veterans Head Injury Program. The study is published in the journal Neurology.

This is the first study in humans to show that recovering memory after brain injury is harder for people who have the E4 type of the apolipoprotein E (APOE) gene ? which is already known to influence Alzheimer?s disease.

"Although APOE has been implicated in traumatic brain injury recovery before, this is the first time that it has been associated with a specific deficit," said lead author Fiona Crawford, PhD, of the Roskamp Institute at USF.

"The findings have implications for understanding repair and recovery after traumatic brain injury, as well as the neurodegenerative mechanisms, and suggest common cellular responses in head injury and Alzheimer?s disease."

The study looked at 110 head-injured patients who were rated for level of traumatic brain injury, assessed for memory function and genotyped at the APOE gene.

Although participants with the E4 form of the APOE gene matched those without the E4 form in terms of age, gender and severity of injury, there were clear differences in memory function between the two groups. The E4 group showed worse recovery of general memory function after injury. Ongoing work at the Roskamp Institute is pursuing the findings.

The study was conducted by researchers at the USF Roskamp Institute, together with the James A. Haley Veterans' Hospital and the Walter Reed Army Medical Center.