Although mild cognitive impairment (MCI) criteria are disputable, characterizing various aspects of operational MCI (O-MCI) may lead to a better understanding of potential modulators of cognitive decline and contribute to more effective public health strategies. The aim of the study is to examine characteristics of community-dwelling elderly people with MCI assessed using Japanese version of Montreal Cognitive Assessment (MoCA-J).

A total of 913 community-dwelling Japanese (65-84 years) participated in health examinations in Tokyo, 2011. The MoCA-J, Mini-Mental State Examination (MMSE), and other physical and mental tests were conducted. Excluded were those with <24 MMSE scores. Those with <26 in MoCA-J were divided into 2 subgroups, (A) participants independent of instrumental activities of daily living (IADL) and no memory complaints and (B) participants independent of IADL with memory complaints or partially dependent on IADL with/without memory complaints. Those with ≥26 in MoCA-J and subgroup (A) of MCI were the normal controls (NCs, 57.4%), and subgroup (B) of MCI was O-MCI, 36.5%. We compared each variable between NC and O-MCI, using logistic regression analysis, adjusted for gender and age.

The majority of all the groups were independent of IADL. The O-MCI characteristics were increased depressive symptom, worse self-rated health, lower systolic blood pressure, poorer intellectual activities, no hobbies, weaker grip strength, and slower than usual walking speed compared to the NC group.

Older persons with O-MCI defined by MoCA-J have partially decreased cognition and physical and sociopsychological functions.