Slowing Down After a Mild Traumatic Brain Injury: A strategy to improve cognitive task performance?
The January issue of the Archives of Clinical Neuropsychology carried a very interesting study entitled, Slowing Down After a Mild Traumatic Brain Injury: A strategy to improve cognitive task performance? The study was authored by Lana J. Ozen and Myra A. Fernandes of the Department of Psychology, University of Waterloo, Waterloo, Ontario, Canada.
The authors noted that “long-term persistent attention and memory difficulties following a mild traumatic brain injury often go undetected on standard neuropsychological tests, despite complaints by mild TBI individuals.” The researches recruited 26 undergraduate students with a self-report of one mild TBI that had occurred at least six months prior and 31 non-head-injured controls. Of the mild TBI group, 17 had sustained their brain injury five years ago or longer. For the purpose of the study, a mild TBI was defined as any strike to the head or any acceleration/deceleration force that resulted in a loss of consciousness lasting at least a couple of seconds and no longer than 30 minutes. Participants could also experience memory loss (amnesia), confusion, and/or disorientation all not exceeding 24 hours in addition to loss of consciousness.
The researchers utilized the Repetition Detection Working Memory Task from Bopp and Verhaeghen (2000) to measure working memory.
The “major finding in the study was that young adults who sustained a mild TBI in their distant past took significantly longer, on average, to accurately identify targets on a working memory task and reported higher levels of anxiety following task completion compared with non-head-injured controls. Moreover, mild TBI participants had identical accuracy performance compared with controls in the low-load working memory condition and, unexpectedly, surpassed control performance in the high-load condition. Post hoc temporal analyses of responses conducted to investigate the unpredicted accuracy boost, revealed that, on average, mild TBI participants made significantly more of the accurate repeat identifications following the target offset in both low-and high-load conditions compared with controls. “
The researchers suggested that mild TBI participants used a slowing strategy that resulted in hit rates that were no different from controls in the low-load condition and rates that were significantly higher than controls in the high-load condition. The researchers concluded that “this is the first study to show significant slowing of information processing speed, with no decrement, but, rather, a boost in accuracy rates, during a working memory task in young adults who have sustained one mild TBI in the distant past. The current findings suggested that the decrease processing speed observed in mild TBI participants is a lasting consequence of their head injury.
For the neuro attorney, this is a very important study as it demonstrates and debunks the myth that all persons with a mild TBI go on to full recovery. It is also important as standardized neuropsychological testing fails to detect this working memory problem.
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