October 25th, 2018

The Vietnam Head Injury Study (VHIS) is a follow-up study of 1,221 Vietnam War veterans with head injuries suffered during the period 1967-1970. The VHIS is a US-based long-term study that is examining the risks of developing cognitive and other problems many years after a head injury, which continues to be common in combat situations. Almost everyone in the study suffered their injury at around 18-20 years of age.

In this phase of the study (phase III), which ran from 2003-2006, the veterans were assessed over five to seven days at the National Naval Medical Centre, Bethesda, Maryland, USA.

The VHIS is assessing the relationship between pre-injury IQ, demographics variables, location of head injury, brain tissue loss and a number of genetic markers with long-term cognitive decline.

This phase of the study revealed that those with head injuries demonstrated a higher degree of cognitive decline 30+ years following their injury compared with a control group of uninjured Vietnam veterans. The decline had become increasingly significant later in life. It also found that pre-injury intelligence was the most consistent predictor of cognitive outcome. The site of the injury did not link to cognitive outcome, but there was a link between atrophy (degeneration of cells probably secondary to the original injury) and long-term cognitive functioning. The study also found an association between the level of cognitive decline following head injury and the possession of specific genetic markers.

It was concluded that while long term cognitive decline was shown to occur in the veterans with head injury, it was determined by multiple factors, most notably pre-injury intelligence.

To read the full medical article as written by our consultant neuropsychiatrist Dr Vanessa Raymont and her colleagues, click here.