The Montreal Cognitive Assessment (MoCA) and Mini Mental State Examination (MMSE) are brief screening instruments for cognitive disorders. Although these instruments have frequently been used in the detection of dementia, there is currently little knowledge on the validity to detect Korsakoff's syndrome (KS) with both screening instruments. KS is a chronic neuropsychiatric disorder associated with profound declarative amnesia after thiamine deficiency. A representative sample of 30 patients with KS and 30 age-, education-, gender- and premorbid-IQ-matched controls was administered the MoCA and MMSE. The area under the receiver operating characteristic curve (AUC) was calculated in addition to the sensitivity, specificity, positive predictive value, and negative predictive value for various cut-off points on the MoCA and MMSE. Compared with the MMSE, the MoCA demonstrated consistently superior psychometric properties and discriminant validity--AUC: MoCA (1.00 SE .003) and MMSE (0.92 SE .033). When applying a cut-off value as suggested in the manuals of both instruments, the MMSE (< 24) misdiagnosed 46.7% of the patients, while the MoCA (< 26) diagnosed all patients correctly. As a screening instrument with the most optimal cut-offs, the MoCA (optimal cutoff point 22/23, 98.3% correctly diagnosed) was superior to the MMSE (optimal cutoff point 26/27, 83.3% correctly diagnosed). We conclude that both tests have adequate psychometric properties as a screening instrument for the detection of KS, but the MoCA is superior to the MMSE for this specific patient population.
Keywords: Alcoholism; Amnesia; Cognitive screening; Korsakoff’s syndrome.; Mini Mental State Examination.