Neuropsychological Functioning Following Complicated Versus Uncomplicated Mild Traumatic Brain Injury
I just received a copy of the February 2009 issue of Brain Injury, The Official Research Journal of the International Brain Injury Association. There, I found an interesting article by Rael T. Lange, Grant L. Iverson and Michael D. Franzen entitled “Neuropsychological Functioning Following Complicated Versus Uncomplicated Mild Traumatic Brain Injury”. (Brain Injury February 2009; 23 (2):83-91.)
The purpose of the study was to examine the neuropsychological functioning in patients following complicated versus uncomplicated mild traumatic brain injury in the first seven days post injury. The researchers assumed that patients with day-of-injury intracranial abnormalities would have worse neuropsychological functioning than patients without these abnormalities. Studies previously conducted had concluded that patients with intracranial abnormalities detected on CT or MRI had worse performance on some neuropsychological measures in the initial days, weeks and months following mild TBI compared to those without such abnormalities.
The researchers selected from an archival database of 465 patients seen as part of the Allegheny General Hospital Trauma Service Clinical Pathway in Pittsburgh, PA for a known or suspected brain injury. For the purposes of the study, only patients who could be classified as sustaining an uncomplicated mild TBI or complicated mild TBI were of interest. Of those 465 patients, 167 patients were classified as either uncomplicated or complicated mild TBI based on CT scan results and a GCS score falling between 13-15. Of that population, 20 patients with uncomplicated mild TBI were selected who matched 20 complicated mild TBI patients. These patients were matched on age, education, gender, ethnicity, days tested post injury and mechanism of injury.
These 40 patients had undergone neuropsychological testing. The cognitive measures used were trail making test part a and part b, controlled oral word association test (COWAT), the Hopkins Verbal Learning Test and selected sub-tests from the WMS-R: Digit Span Forward, Digit Span Backward, Logical Memory I, Logical Memory II, Visual Reproduction I, and Visual Reproduction II.
Overall, the result for providing some support for the hypothesis that patients with complicated mild TBI would have worse neuropsychological functioning. Patients with complicated mild TBI did perform worse on several measures and had a greater proportion of low scores on some measures when compared to the uncomplicated group. However, a global reduction of functioning across all measures in the complicated mild TBI group was not found. The effect of complicated mild TBI on neuropsychological functioning was lessened when only subjects with GCS scores equaled a 15 were compared.
The researchers concluded that the data suggested that there are some differences in neuropsychological functioning in the acute phase of recovery. However, they noted that the differences in neuropsychological functioning were found on only a few measures and the effect size of these differences were lower than expected.