P1‐611: operationalization of diagnostic criteria for mild cognitive impairment

Mild cognitive impairment (MCI) describes the intermediate status between physiological cognitive aging and dementia. The recommended cut-off score for cognitive impairment is a performance of 1-1.5 standard deviations (SD) below the age and educational peers in at least one cognitive domain. Up to date, there are no clear criteria regarding the cut-off score or the number of used subtests. We examined the MCI prevalence rates depending on different cut-off scores as well as number of used subtests. We included 2898 participants out of the third examination of the Heinz Nixdorf Recall study (n=3087, 68.5 years, 49% men, 2010-2015) with complete cognitive assessment. MCI was diagnosed based on the following criteria: presence of subjective cognitive impairment, no impairment in activities of daily living, no dementia diagnosis and presence of objective impairment. The following four operationalization models were used to assess objective impairment: a) Five subtests and 1 SD. b) Eight subtests and 1 SD. c) Five subtest and 1.5 SD. d) Eight subtests and 1.5 SD. Row data were z transformed according to three age and education groups. A subtest was rated as impaired depending on the respective operationalization model. MCI prevalence rates were calculated. The following MCI prevalence rates were found for the four models: a) Five subtests and 1 SD: 14.4% (n=417) b) Eight subtests and 1 SD: 17.7% (n=512). c) Five subtests and 1.5 SD: 6.4% (n=185). d) Eight subtests and 1.5 SD: 9.5% (n=274). The different operationalization models have a strong influence on the prevalence of MCI. This underlines the urgent need for recommendations with clear cut-off scores to define objective impairment. Furthermore, recommendations regarding the used subtests would probably help to better identify this very heterogeneous syndrome.