Presentation M P24

M P24 (Poster Presentation):
Are Memory Functioning and Cognitive Response Bias Different in Mild Traumatic Brain Injury Claimants With and Without MRI-Detected Intracranial Abnormalities?

Presented by: Douglas P. Gross

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Abada A1, Colangelo A1, Haws C1, Russell K1, Gross DP2

  1. Workers' Compensation Board-Alberta/ Millard Health, Edmonton, Canada
  2. University of Alberta, Edmonton, Canada



The literature on mild traumatic brain injury (MTBI) indicates that the majority of individuals with a minor head injury (including those injured at work in a compensation setting) have uncomplicated recovery trajectories. However, some individuals report persisting symptoms despite medical treatment and rehabilitation. Some of these persisting symptoms may be due to MRI-detected intracranial abnormalities, although there is evidence that some of the observed persisting symptoms may be attributable to factors other than the MTBI. We compared memory functioning and cognitive response bias in workers' compensation MTBI claimants with and without MRI-detected intracranial abnormalities.


Between 2007 and 2011, approximately 80% of workers’ compensation claimants who have been triaged to the Millard Health Head Trauma Rehabilitation Program in Edmonton, Alberta sustained a MTBI. Group 1 clients had normal neuro-imaging and expected to have full resolution of symptoms within three months post-injury, whereas Group 2 clients sustained head injuries with intracranial abnormalities and expected to have persisting long-term sequelae given permanent damage to the brain tissue. The present study examined whether Group 1 and 2 clients differed significantly with respect to indices of memory functioning and cognitive response bias (i.e. empirically validated measures of effort level testing).


Preliminary analysis indicates that on a test of response bias, 127 Group 1 claimants (M = 85.7, SD = 15.9) recalled less information after a delay of 30 minutes compared to 102 Group 2 claimants (M = 91.7, SD = 12.2) and this difference was statistically significant (t(227) = 3.18, p = .002). Also, Group 1 claimants (M = 72.1, SD = 23.8) performed significantly worse than Group 2 claimants (M = 78.6, SD = 19.6) on a recognition task (t(227) = 2.21, p = .028).


Compared to claimants with intracranial abnormalities, those with normal imaging performed substantially worse and inconsistently. Results suggest that incentive-based disability is a significant factor in the initial symptom presentation of claimants with normal neuro-imaging. The results indicate a need for different rehabilitation approaches between claimants with and without MRI-detected intracranial abnormalities.

Schedule Details

Monday September 29
12:45 - 13:45 Poster Viewing
Session: Disability measurement