A-011 Stability of Impairment Rating Discrepancies in a Longitudinal Observational Alzheimer’s Study

Abstract

Abstract Objective The present study investigated frequency and 12-month persistence of discrepant Clinical Dementia Rating (CDR) and comprehensive neuropsychological assessment ratings of impairment. Methods We examined CDR and neuropsychological test scores from year 1 and 2 visits of 162 adults enrolled in a longitudinal observational study. Neuropsychological measures included Wide Range Achievement Test, American National Adult Reading Test, Rey Auditory Verbal Learning Test, Brief Visuospatial Memory Test-Revised, Dementia Rating Scale 2nd edition, Boston Naming, Verbal Fluency/Color Word Interference from the Delis-Kaplan Executive Function System, Judgment of Line Orientation, Trail Making Test, Symbol Digit Modalities Test, and Digit Span/Letter Number Sequencing from The Wechsler Adult Intelligence Scale 4th edition. Discrepancies were defined as: CDR = 0 and 2 test impairments, CDR = 0.5 and > 5 or 0 impairments, CDR = 1 and 0 impairments. Results Including all test domains, 40.1% of participants in year 1 and 44.3% in year 2 showed discrepancies. 69% maintained this discrepancy at year 2 and 68% of these showed no change in discrepancy type. Considering only memory tests, 37% of participants in year 1 and 28.4% in year 2 showed discrepancies, with 45% maintaining at year 2 (74% showing no change in discrepancy type). A majority of discrepancies observed in both years 1 and 2 revealed the CDR was under reporting impairment compared to the neuropsychological battery year. Conclusions The results provide evidence that within our study population, impairment as rated by the CDR frequently does not match the level of measured cognitive impairment and this observation is stable year to year.