Head injuries worsen memory and thinking decades later

Alzheimer’s Research UK funded research at UCL has found people who experience head injuries in their 50’s or younger score lower than expected on memory and thinking tests at age 70.

Head injuries did not appear to contribute to brain damage characteristic of Alzheimer’s disease, but might make people more vulnerable to dementia symptoms. The scientific journal the Annals of Clinical and Translational Neurology published the findings.

Dr Sarah-Naomi James from UCL said:

“Here we found compelling evidence that head injuries in early or mid-life can have a small but significant impact on brain health and thinking skills in the long term. It might be that a head injury makes the brain more vulnerable to, or accelerates, the normal brain ageing process. “It looks like head injuries can make our brains more vulnerable to the normal effects of ageing. We have not found evidence that a head injury would cause dementia, but it could exacerbate or accelerate some dementia symptoms.”

The study involved 502 volunteers from the Insight 46 study which has been following participants since their birth in the same week in 1946.

At age 53, the volunteers were asked ‘Have you ever been knocked unconscious?’ to see whether they had ever sustained a substantial head injury.  And then around age 70  the study participants underwent brain scans and they took a suite of memory and thinking tests.

The researchers found that 70-year-olds who had experienced a serious head injury more than 15 years earlier performed slightly worse than expected on cognitive tests for attention and quick thinking. They also had smaller brain volumes (by 1%) and differences in brain microstructural integrity, in line with evidence from previous studies, which may explain the subtle cognitive differences.

The researchers did not find any differences in levels of the amyloid protein, implicated in Alzheimer’s disease, or other signs of Alzheimer’s-related damage.

The researchers did not have data on the frequency, severity or cause of the head injuries, to see if long-term impacts might have been even greater for certain people.

Dr Susan Kohlhaas, Director of Research at Alzheimer’s Research UK, said: “With millions of people around the world experiencing head injuries every year, reducing the risk of sustaining these injuries should be an important public health goal. Looking for brain shrinkage and other signs of damage soon after a head injury, are important steps towards understanding how brain injury is related to brain health and long-term thinking and memory problems. “As the UK’s leading dementia research charity we are pleased to have funded this research and these findings add to our understanding of the factors that affect the health of the brain. While head injuries are usually impossible to predict or avoid, there are steps that we can all take to help keep our brains healthy as we age. “That’s why Alzheimer’s Research UK has launched the thinkbrainhealth.org.uk campaign to engage people with this important aspect of their health and to make the public more aware of the things they can do to support their brain health.”

Lauren Pulling, CEO of The Drake Foundation, which funds research on head impacts in sport, said: “These new findings add to the growing evidence base showing that head impacts can have tangible, long-term effects on the brain. With this in mind, and in addition to further research, it is essential that sport’s governing bodies take note and use a common-sense approach to universally minimise players’ risk of head injury, right through from grassroots to elite levels.”

The study was funded by Alzheimer’s Research UK, Dementias Platform UK, the Wolfson Foundation and The Drake Foundation, and involved researchers at UCL, London School of Hygiene and Tropical Medicine, King’s College London, University of Gothenburg and the UK Dementia Research Institute.