Background: The Montreal Cognitive Assessment (MoCA) has good sensitivity for mild cognitive impairment, but specificity is low when the original cut-off (25/26) is used. We aim to revise the cut-off on the German MoCA for its use in clinical routine.
Methods: Data were analyzed from 496 Memory Clinic outpatients (447 individuals with a neurocognitive disorder; 49 with cognitive normal findings) and from 283 normal controls. Cut-offs were identified based on (a) Youden's index and (b) the 10th percentile of the control group.
Results: A cut-off of 23/24 on the MoCA had better correct classification rates than the MMSE and the original MoCA cut-off. Compared to the original MoCA cut-off, the cut-off of 23/24 points had higher specificity (92% vs 63%), but lower sensitivity (65% vs 86%). Introducing two separate cut-offs increased diagnostic accuracies with 92% specificity (23/24 points) and 91% sensitivity (26/27 points). Scores between these two cut-offs require further examinations.
Conclusions: Using two separate cut-offs for the MoCA combined with scores in an indecisive area enhances the accuracy of cognitive screening.
Keywords: Area under curve; Cognitive dysfunction; Mental status and dementia tests; Mini Mental State Examination; Montreal Cognitive Assessment; Neurocognitive disorders; Neuropsychology; ROC curve; Sensitivity and specificity.