Do Education and Premorbid Intelligence Predict Cognitive Decline Over 1 Year in Rural Patients with Dementia?

Introduction: Education and premorbid intelligence have been used to predict disease trajectory in dementia. However, there is conflicting evidence regarding their independent predictive ability. This study aims to investigate whether education and premorbid intelligence predict cognitive and functional decline in rural dementia patients over 1 year. Methods: Data from 614 rural patients was analyzed for the association between (a) years of education and (b) premorbid intelligence [Premorbid Verbal IQ] and cognitive function [MMSE, CDR-SB, NPI, FAQ] through linear regression analysis as an overall group sample, and stratified into Subjective Cognitive Impairment, Mild Cognitive Impairment, Alzheimer’s Disease, and Non-Alzheimer’s Disease dementia groups. Premorbid verbal IQ was estimated using the Wechsler Test of Adult Reading & Wide Range Achievement Test 4th Edition, after norming each was scored on a scale of 100. Results: Higher Premorbid Verbal IQ score predicted a smaller decline in cognition in the overall group sample and reduced caregiver dependence in the non-AD dementia group 1-year post-diagnosis. Education was not a statistically significant predictive factor of cognition 1-year post-diagnosis. Conclusion: Higher premorbid intelligence may be a better 1-year prognostic indicator of cognition and function than education level in rural populations.