B-44protective Effects of Premorbid Cognitive Reserve on Neuropsychological Performance after Brain Injury

Objective: Research has found that cognitive reserve, as indicated by premorbid intelligence estimates, serves as a protective factor against cognitive decline in several neuropsychiatric conditions including schizophrenia, depression, and bipolar disorders. We investigated whether the phenomenon of cognitive reserve as a protective factor against neurocognitive dysfunction extends to traumatic brain injury (TBI), even with the occurrence of posttraumatic amnesia (PTA), a strong indicator of TBI severity. Method: Clinical records of 120 adults screening positive for TBI were analyzed. Neuropsychological measures included: Repeatable Battery for the Assessment of Neuropsychological Status, Grooved Pegboard, Trails, WAIS-IV Digit Span, Numbers and Letters Test, and Delis–Kaplan Verbal Fluency and Interference Tests. Predictors included PTA per structured clinical interview and premorbid intelligence as estimated by the Wechsler Test of Adult Reading and Shipley Vocabulary tests. Results: Occurrence of PTA was significantly associated with lower premorbid intelligence. Further analysis indicated an interaction effect of PTA and premorbid intelligence for several measures of attention, verbal fluency, and affect recognition (p < .05), such that in the lower IQ group, PTA was associated with lower scores on these neurocognitive measures. However, PTA was not associated with lower cognitive performances in the higher IQ group. Significant interactions were not found for measures of fine motor functions and processing speed. Conclusion: Present analysis indicates that premorbid intelligence likely does serve to protect neuropsychological functioning following TBI even with the occurrence of PTA. This expands the range in which this phenomenon of cognitive reserve has been demonstrated and highlights the importance of accessible education.