Altered Executive Function in Pre-Mild Cognitive Impairment.

BACKGROUND: For the early detection of Alzheimer's disease (AD), there is increasing interest in pre-mild cognitive impairment (pre-MCI).

OBJECTIVE: We explored the neuropsychological characteristics in a group of pre-MCI and cognitively normal (CN) elderly individuals, with the aim of providing measures sensitive to cognitive change in pre-MCI.

METHODS: We included 188 CN elderly and 77 individuals with pre-MCI. All participants underwent comprehensive clinical and neuropsychological assessment. We compared 17 cognitive tests between the CN and pre-MCI groups by using one-way ANOVAs with false discovery rate correction for multiple comparisons. Pearson's correlations were also obtained between episodic memory and executive function tests in the pre-MCI group.

RESULTS: The pre-MCI group showed significantly lower scores for visual immediate recall, fluency tests, and Stroop color naming in the color-word incongruent condition than the CN group (p < 0.05). Most of these executive function measures were significantly correlated with episodic memory (p < 0.05). There were no significant group-differences in other tests assessing attention, verbal memory, visuospatial ability, and language.

CONCLUSION: Our findings indicate that poor executive function especially demanding inhibition and goal-directed behaviors within time limit could be the characteristics of the very early cognitive sign in the course of AD.