Progression to Dementia in Probable and Possible Mild Cognitive Impairment—Reply

In reply

We thank Panza and colleagues for their interesting observation regarding the discrepancy in the incidence of dementia in MCI between the CHS-CS¹ and the ILSA.² One of the most important epidemiological problems in the study of MCI and dementia is the ascertainment of cases. Studies using a 2-stage screening protocol risk missing MCI and early dementia cases (eg, a cut-off of 23 in Mini-Mental State Examination score).² In the CHS-CS, all subjects had detailed neurological and neuropsychological evaluations, and none of them went through a screening phase. Had we used a cut-off score of 80 in the Modified Mini-Mental State Examination (which is the accepted cut-off for identifying cognitively impaired subjects, similar to a Mini-Mental State Examination score of about 23),³ we would have failed to identify 86% of the subjects eventually classified as MCI and 53% of those with dementia.