Date of Submission


Degree Type


Degree Name

Doctor of Psychology (PsyD)



Department Chair

Robert A DiTomasso, PhD, ABPP


The physical, cognitive, behavioral, and emotional sequelae of brain injury have been shown to exert a substantial negative impact on everyday work-related and social functioning. Accordingly, accurate measurement of any associated cognitive decline is of paramount importance, and clinicians often face the challenge of estimating the patient’s level of intellectual functioning prior to the brain pathology. This study examined the influence of environmental factors, such as education quality on a demographically based formula for estimating premorbid intelligence and focused primarily on an adjusted variable (reading level vs. years of education). The results showed that for the entire sample of the non-brain injured and the brain injured participants, only one of the variables used in the original Barona formula approached significance in predicting WASI FSIQ: gender. After adding the quality of education variable, the fit of the regression model significantly improved by 18%. Surprisingly, when separating the clinical and non-clinical sample, the regression variables did not perform as well as expected. For the non-brain injured control sample, the improvement of the model only approached significance after including reading score. In contrast, results for the TBI sample indicated a significant improvement. Further, variables such as percentage of minorities in a school, school location’s poverty level and educational quality were found to be closely associated. Future research should continue to identify environmental factors that might influence scores on measures of premorbid intelligence for a more individually tailored approach to diagnosis and treatment.

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Psychology Commons