Background: This aim of this study was to assess the clinical utility of the Montreal Cognitive Assessment (MoCA) as a screening instrument for cognitive impairment in patients referred to a memory clinic, alone and in combination with the Mini-Mental State Examination (MMSE).
Methods: This was a pragmatic prospective study of consecutive referrals attending a memory clinic (n = 150) over an 18-month period. Patients were diagnosed using standard clinical diagnostic criteria for dementia (DSM-IV) and mild cognitive impairment (MCI; cognitive impairment prevalence = 43%) independent of MoCA test scores.
Results: MoCA proved acceptable to patients and was quick and easy to use. Using the cut-offs for MoCA and MMSE specified in the index paper (≥26/30), MoCA was more sensitive than MMSE (0.97 vs 0.65) but less specific (0.60 vs 0.89), with better diagnostic accuracy (area under Receiver Operating Characteristic curve 0.91 vs 0.83). Downward adjustment of the MoCA cut-off to ≥20/30 maximized test accuracy and improved specificity (0.95) for some loss of sensitivity (0.63). Combining MoCA with the MMSE - either in series or in parallel - did not improve diagnostic utility above that with either test alone.
Conclusions: In a memory clinic population, MoCA proved sensitive for the diagnosis of cognitive impairment. Use of a cut-off lower than that specified in the index study may be required to improve overall test accuracy and specificity for some loss of sensitivity in populations with a high prior probability of cognitive impairment. Combining the Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE) with the MMSE did not improve diagnostic utility.