The CAMCOG: a useful screening instrument for dementia in stroke patients

BACKGROUND and PURPOSE: Most mental screening tests focus on the detection of cognitive deficits compatible with Alzheimer's disease. Stroke patients who develop a dementia syndrome, however, constitute a more heterogeneous group with both cortical and subcortical disturbances. We assessed the diagnostic accuracy of the CAMCOG (the cognitive and self-contained part of the Cambridge Examination for Mental Disorders of the Elderly) and the Mini-Mental State Examination (MMSE) for dementia in patients with a recent stroke. METHODS: In patients aged 55 and older who were admitted in the Rotterdam Stroke Databank, cognitive functioning was assessed between 3 and 9 months after the most recent stroke. The "gold standard" diagnosis of dementia was compatible with the criteria of the Diagnostic and Statistical Manual of Mental Disorders, Third Edition, Revised. The CAMCOG and MMSE scores were obtained independent of the diagnostic procedure. RESULTS: Of 300 consecutive patients, 71 (23.7%) were demented. Sixteen severely demented patients could not be tested and were excluded. The CAMCOG and MMSE scores were significantly related to dementia (both P<0.0001) in a logistic regression model. Receiver operating characteristic analysis showed that the CAMCOG was a more accurate screening instrument (area under the curve for CAMCOG, 0.95; for MMSE, 0.90). Two other clinical variables independently improved the diagnostic accuracy of the MMSE and CAMCOG: patients with a left hemispheric lesion had a lower (odds ratio, 0.3; 95% confidence interval, 0.1 to 0.7), and patients with hemorrhagic stroke had a greater chance of being demented (odds ratio, 3; 95% confidence interval, 1 to 10). The effect of left hemispheric lesion as an independent diagnostic factor could not be explained by selection or its association with aphasia alone. CONCLUSIONS: The CAMCOG is a feasible instrument for use in patients with a recent transient ischemic attack or stroke. It is a more accurate screening tool for dementia than the MMSE, especially when type and site of stroke are taken into account.