Neurocognitive Deficits and Effects of Cognitive Reserve in Mild Cognitive Impairment.

BACKGROUND/AIMS: Mild cognitive impairment (MCI) is a frequent syndrome in the older population, which involves an increased risk to develop Alzheimer's disease (AD). The latter can be modified by the cognitive reserve, which can be operationalized by the length of school education. MCI can be differentiated into four subtypes according to the cognitive domains involved: amnestic MCI, multiple-domain amnestic MCI, non-amnestic MCI and multiple-domain non-amnestic MCI. While neurocognitive deficits are a constituent of the diagnosis of these subtypes, the question of how they refer to the cognitive reserve still needs to be clarified. METHODS: We examined neuropsychological deficits in healthy controls, patients with MCI and patients with mild AD (n = 485) derived from a memory clinic. To reduce the number of neuropsychological variables, a factor analysis with varimax rotation was calculated. In a second step, diagnostic groups including MCI subtypes were compared with respect to their clinical and neuropsychological characteristics including cognitive reserve. RESULTS: Most MCI patients showed the amnestic multiple-domain subtype followed by the pure amnestic subtype, while the non-amnestic subtypes were rare. The amnestic subtype displayed a significantly higher level of cognitive reserve and higher MMSE scores than the amnestic multiple-domain subtype, which was in most cases characterized by additional psychomotor and executive deficits. CONCLUSIONS: These findings confirm earlier reports revealing that the amnestic multiple-domain subtype is the most frequent one and indicating that a high cognitive reserve may primarily prevent psychomotor and executive deficits in MCI.

The Positivity Effect on the Intensity of Experienced Emotion and Memory Performance in Mild Cognitive Impairment and Dementia.

AIMS: We examined the 'positivity effect' on memory performance in mild cognitive impairment (MCI) and dementia patients. METHODS: In 109 subjects (28 controls, 32 with MCI, 27 with mild and 32 with moderate dementia), we investigated free recalls (immediate and delayed) and recognition of 12 pictures. Moreover, the emotional valence of the pictures perceived and the emotions evoked in the subjects were evaluated. RESULTS: Patients with mild and moderate dementia recalled fewer pictures than those with MCI or the healthy controls. Across the groups, the positive pictures were better memorized and induced a higher arousal than the negative or neutral ones. CONCLUSIONS: Our findings indicate a positivity effect on memory performance and intensity of experience not only in healthy elderly patients but also in those with MCI or mild and moderate dementia. This effect does not refer to the compliance of the patients investigated since they perceived and experienced the pictures in the expected way.