The sensitivity and specificity of cognitive screening instruments to detect cognitive impairment in older adults with severe psychiatric illness

Background: Older adults with severe psychiatric illness are often treated at community mental health centers (CMHCs) and these individuals commonly have numerous risk factors for cognitive impairment (CI). Brief cognitive screening instruments are frequently used to evaluate cognitive functioning in CMHCs, but the validity of these measures for detecting CI has not been adequately evaluated in this patient population. Objectives: To determine the sensitivity and specificity of 2 cognitive screening measures (the Mini-Mental Status Examination [MMSE] and the Stroop Color and Word Test [SCWT]) for detecting CI in a sample of older adults with severe psychiatric illness. Methods: Data were collected from 52 older adults receiving services at a CMHC. Diagnosis of CI was made by a neuropsychologist. Sensitivity and specificity coefficients for 2 cutoff scores for the MMSE and the SCWT were calculated. Results: A cutoff score of 25 on the MMSE yielded a sensitivity of 43.3% and a specificity of 90.4% for detecting CI, whereas a cutoff score of 21 yielded sensitivity of 13.1% and 100% specificity. Using an age- and education-corrected scaled score (SS) on the SCWT falling at or below 7 as the criterion the SCWT had 88.8% sensitivity and 36.8% specificity, whereas a cutoff score of 5 or below yielded sensitivity of 59.2% and specificity of 57.8%. Conclusions: Overall, the MMSE was found to be the more clinically useful cognitive screening tool for use in CMHC. Yet, because of the poor sensitivity of the MMSE for detecting CI in this patient population, alternative screening methods should be explored.