Utility of the Clinical Dementia Rating Scale in Detecting Autopsy-Proven Dementia in Patients with Low Education
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BACKGROUND AND OBJECTIVE: The Clinical Dementia Rating scale (CDR) assesses impairment in 6 cognitive and functional domains to stage cognitive decline and dementia. Each domain is scored from 0 (no impairment) to 3 (severe impairment), and these scores are summed to a sum-of-boxes (CDR-SB) score ranging from 0 to 18. The CDR-SB score has shown high reliability in staging dementia. However, no studies have determined whether the CDR remains effective when applied to less-educated individuals. This study investigated the sensitivity and specificity of the CDR-SB score in detecting dementia associated with autopsy-proven AD in patients with less than 12 years of education. HYPOTHESIS: Using the validated CDR-SB cut score for mild dementia (4.5) to detect autopsy-proven AD in this population was hypothesized to yield low sensitivity and/or specificity (i.e. <70%). A higher cut score was expected to be required for optimal sensitivity/specificity. METHODS: Participants from the National Alzheimerﾒs Coordinating Center Uniform Data Set with less than 12 years of education were divided into two cohorts (autopsy-proven AD and normal age-related brain changes), matched for age and sex, and excluded if other major neurological diseases were present (n = 34; 17 per cohort). Receiver Operating Characteristic (ROC) analysis was performed to determine the sensitivity and specificity of CDR-SB scores in discriminating between subjects with autopsy-proven AD and those with normal age-related brain changes. RESULTS: The validated CDR-SB cut score for mild dementia (4.5) correctly classified 10 of 17 patients with normal age-related brain changes and 16 of 17 with autopsy-proven AD (sensitivity = .941, specificity = .588). These data reflect the unexpected presence of 7 patients with clinically-diagnosed dementia in the normal cohort and 1 patient without clinically-diagnosed dementia in the autopsy-proven AD cohort. The optimal cut score was found to be 9.5, correctly classifying 15 of 17 patients with normal age-related brain changes and 14 of 17 with autopsy-proven AD (sensitivity = .824, specificity = .882). DISCUSSION: In patients with <12 years of education, the optimal CDR-SB cut score to detect AD-related dementia (9.5) is in a range associated with moderate dementia, which may be too high for clinical utility. Although numerous neurological syndromes were excluded, factors other than education may have contributed to high CDR-SB scores in the comparison group. Further research in larger samples is needed to validate the results of this preliminary investigation.
The 56th Annual Medical Student Research Forum at UT Southwestern Medical Center (Tuesday, January 23, 2018, 2-5 p.m., D1.600)
Guidelines as Topic
Mental Status and Dementia Tests
Psychiatric Status Rating Scales
Li, C., LoBue, C., Schaffert, J., & Cullum, C. Munro (2018, January 23). Utility of the clinical dementia rating scale in detecting autopsy-proven dementia in patients with low education. Poster session presented at the 56th Annual Medical Student Research Forum, Dallas, TX. Retrieved from https://hdl.handle.net/2152.5/5351