Study shows brain damage increases risk of dementia decades later

Researchers at Imperial College London have discovered that a single serious head injury can lead to brain damage several decades later, even though the patient seems to recover completely in the short term.

Their study used a novel positron emission tomography (PET) imaging technique to examine the biochemistry of 21 men and women who suffered traumatic brain injury (TBI) following an accident or accident. An aggression between 18 and 35 years ago. They were compared to a demographic and educational matched control group of 11 individuals with no history of injury.

The results, published in Science Translational Medicine, showed that TBI victims were much more likely to have high levels of harmful tau protein in the brain than the control group or the general population. Scientists are increasingly seeing tau accumulation as a key indicator of the development of neurodegeneration, which will likely be followed by Alzheimer's disease or some other form of dementia. The TBI group, who was between 29 and 72 years old, also had lower scores than the controls on memory and cognitive tests.

"A single moderate to severe injury can trigger a process leading to chronic neurodegeneration and dementia later in life," said David Sharp, project manager, professor of neurology at Imperial Oil. "The risk of neurodegeneration appears to be dose-dependent, caused either by a single serious TBI or by repeated exposure to more minor injuries, such as in American football and some other sports."

The type of injury in the study group was "serious enough to keep the patient in hospital for a few days but not catastrophic," said Professor Sharp, who runs a brain injury treatment clinic at Charing Cross Hospital. "A few months later, you would not have known that they had been injured."

But a separate study recently published in the journal Brain contains more positive information for people with head injuries. Professors Sharp and Imperial College found that about one-third of people with cognitive impairment as a result of brain trauma have significantly improved after treatment with methylphenidate, a drug better known as Ritalin. , its brand name, which is prescribed for Attention Deficit Hyperactivity Disorder.

The researchers conducted a clinical trial of 40 people with cognitive consequences of brain injury. Half of the participants were randomly selected to receive methylphenidate and the other half took a placebo. The drug significantly boosted mood and cognition in about one-third of those who took it, but not in the placebo group.

More significantly, researchers were able to determine which participants would benefit from methylphenidate by performing another type of brain scan called Spect (single photon emission tomography). Those who had unusually low levels of dopamine, a key neurotransmitter that transmitted chemical messages to the brain, improved their methylphenidate treatment, but not the other victims of head trauma. The drug increases the activity of neural dopamine.

Professor Sharp said the research tests people with long-term cognitive damage caused by brain injury to determine if they could benefit from Ritalin. "No such thing is happening right now," he said. "Doctors are too negative about TBI. We must be more aggressive in the way we treat people. "