Agreement and conversion formula between mini-mental state examination and montreal cognitive assessment in an outpatient sample

AIM To explore the agreement between the mini-mental state examination (MMSE) and montreal cognitive assessment (MoCA) within community dwelling older patients attending an old age psychiatry service and to derive and test a conversion formula between the two scales. METHODS Prospective study of consecutive patients attending outpatient services. Both tests were administered by the same researcher on the same day in random order. RESULTS The total sample (n = 135) was randomly divided into two groups. One to derive a conversion rule (n = 70), and a second (n = 65) in which this rule was tested. The agreement (Pearson’s r) of MMSE and MoCA was 0.86 (P < 0.001), and Lin’s concordance correlation coefficient (CCC) was 0.57 (95%CI: 0.45-0.66). In the second sample MoCA scores were converted to MMSE scores according to a conversion rule from the first sample which achieved agreement with the original MMSE scores of 0.89 (Pearson’s r, P < 0.001) and CCC of 0.88 (95%CI: 0.82-0.92). CONCLUSION Although the two scales overlap considerably, the agreement is modest. The conversion rule derived herein demonstrated promising accuracy and warrants further testing in other populations.