Impairment of activities of daily living requiring memory or complex reasoning as part of the MCI syndrome

BACKGROUND: Mild Cognitive Impairment (MCI) is a borderline state between age-associated cognitive decline and mild dementia. MCI is separated from mild dementia by an absence of global intellectual deterioration and the preservation of activities of daily living (ADL). However, even mild degrees of cognitive deterioration are known to have negative effects on complex ADL. OBJECTIVES: To examine whether patients with MCI have impaired ADL as compared to healthy controls, which areas of ADL are particularly involved, and whether limitations on ADL are associated with demographical or clinical data. METHODS: Forty-eight patients with MCI diagnosed according to research criteria and 42 cognitively unimpaired controls were enrolled. Cognitive function was inter alia assessed by the MMSE, complex ADL by the ADCS-MCI-ADL scale. Frequency distributions were compared between patients and controls using chi-square tests. Mean values were examined for statistically significant differences using Kruskal-Wallis tests. A Bonferroni correction for multiple comparisons was applied to the comparison of the 18 areas of the ADCS-MCI-ADL scale. Associations between ADL and biographical or clinical data were analysed using non-parametric correlations. RESULTS: The overall score on the ADCS-MCI-ADL scale was significantly lower in the MCI group. Patients performed significantly worse on 14 out of 18 activities. Activities involving memory or complex reasoning were particularly impaired, whereas more basic activities were unimpaired. There were no statistically significant associations of the ADCS-MCI-ADL overall score with age, years of formal education, gender, or number of cognitive domains affected in the group of MCI patients. However, there was a statistically significant association between the ADCS-MCI-ADL and the MMSE score. CONCLUSION: MCI patients may be impaired in complex ADL.