THE MINI-MENTAL-STATE-EXAM AS A PREDICTOR OF NEUROPSYCHOLOGICAL FUNCTIONING AFTER CARDIAC-SURGERY

Objective: The present longitudinal study was designed to: 1) determin e the ability of the Mini Mental State Exam (MMSE) to predict neuropsy chologic impairment based on neuropsychologic testing five to seven da ys and six weeks after cardiac surgery; and 2) to determine whether th e traditional or the education-related MMSE norms are more appropriate to use for this purpose. Method: The day before surgery (T1), before hospital discharge (T2), and six weeks after surgery (T3), 247 subject s completed a battery of five neuropsychologic tests. Subjects also co mpleted the Center for Epidemiological Studies Depression Scale and th e Speilberger State-Trait Anxiety Inventory. Subjects completed the MM SE two to three days after surgery. Results: Stepwise regression analy ses revealed that the MMSE significantly predicted only a small portio n of the variance in neuropsychologic test performance at T2, and to a n even lesser extent at T3, over and above the demographic variables. In assessing the association between an impairment score (derived from the neuropsychologic test battery) and the MMSE, we found that the tr aditional MMSE cut-off score maximized specificity (number of true neg atives) while the education-adjusted MMSE cut-off scores maximized sen sitivity (number of true positives). Conclusions: These results sugges t that although the MMSE is widely used to assess cognitive mental sta tus, it may have limited value in identifying patients with cognitive impairment post-cardiac surgery, and special attention must be paid to the cut-off scores used in interpreting the MMSE.