25% Drop in Thinking and Memory Skills Caused By Mild Traumatic Brain Injury
Been feeling a little foggy lately? Have you been more confused than usual or a bit forgetful? A study published in the July 16, 2014, online issue of Neurology, the medical journal of the American Academy of Neurology, suggests that you might have gently bumped your head a week ago and are still feeling the effects.
The study compared 44 people with a mild traumatic brain injury (TBI) and nine people with a moderate traumatic brain injury to thirty three people with no brain injury. All of the participants underwent cognitive and memory testing. They also had diffusion tensor imaging scans, a type of MRI scan that is more sensitive than traditional MRI for detecting damage to brain cells and helps map fiber tracts that connect brain regions. The people with brain injuries had their scans an average of six days after the injury.
The study found that patient scores on the verbal letter fluency task, a test of thinking and memory skills, were 25 percent lower than in those who had not suffered any brain injury which supported the position that even mild traumatic brain injury may cause cognitive and memory problems days later. One year after the injury, twenty three of those with injuries had another scan and took the cognitive tests again. The scores on thinking and memory tests were the same for people with brain injuries and those with no injuries, but there were still areas of brain damage in people who had suffered injuries.
“Most of the studies thus far have focused on people with severe and chronic traumatic brain injury,” said study author Andrew Blamire, PhD, of Newcastle University in the United Kingdom. “We studied patients who had suffered clinically mild injuries often from common accidents such as falling from a bicycle, or slow speed car accidents. This finding is especially important, as 90 percent of all traumatic brain injuries are mild to moderate.”
Even mild traumatic brain injury can cause significant brain abnormalities
These results concurred with the findings of a 2012 study by Virginia Commonwealth University School of Medicine researchers who found that even mild head injuries can cause significant abnormalities in brain function that last for several days. These abnormalities may explain the neurological symptoms experienced by some individuals who have experienced a head injury associated with sports, accidents or combat.
The VCU team, led by Kimberle M. Jacobs, Ph.D., associate professor in the Department of Anatomy and Neurobiology, demonstrated for the first time that mild injury can cause structural disruption of axons in the brain while also changing the way the neurons fire in areas where they have not been structurally altered. Axons are nerve fibers in the brain responsible for conducting electrical impulses.
Those findings, which were published in the May 2012 issue of the Journal of Neuroscience, were important because they gave researchers a better understanding of what structural or functional changes in the brain underlie posttraumatic disorders.
10,000,000 cases of traumatic brain injury diagnosed every year
It is estimated that there are 10 million cases of traumatic brain injury globally every year with mild traumatic brain injuries being responsible for 70-90% of these.
Current literature suggests that mild traumatic brain injuries cause changes in brain tissues and have important long-term consequences on cognitive function. Deficits have been described in attention, memory, verbal learning and processing speed and may occur in 15-25% of those suffering one of these injuries.
Previous research has shown that even a mild case of TBI can result in long-lasting neurological issues that include slowing of cognitive processes, confusion, chronic headache, post-traumatic stress disorder and depression.
