Single-Domain Amnestic Mild Cognitive Impairment Identified by Cluster Analysis Predicts Alzheimer's Disease in the European Prospective DESCRIPA Study

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.

Section: Discussionsupporting

confidence: 63%

Section: Introductionmentioning

confidence: 99%

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Neurocognitive Deficits and Effects of Cognitive Reserve in Mild Cognitive Impairment

Andrejeva

Knebel²,

Santos³

et al. 2016

“…Amnestic MCI has been suggested to reflect the pathology of the Alzheimer type and non-amnestic MCI to be prodromal dementia of other etiologies [5,37,38,39]. This separation is not entirely clear in our study.…”

Section: Discussionmentioning

confidence: 55%

Prognostic Accuracy of Mild Cognitive Impairment Subtypes at Different Cut-Off Levels

Göthlin

Eckerström

Rolstad

et al. 2017

Background/Aims: The prognostic accuracy of mild cognitive impairment (MCI) in clinical settings is debated, variable across criteria, cut-offs, subtypes, and follow-up time. We aimed to estimate the prognostic accuracy of MCI and the MCI subtypes for dementia using three different cut-off levels. Methods: Memory clinic patients were followed for 2 (n = 317, age 63.7 ± 7.8) and 4-6 (n = 168, age 62.6 ± 7.4) years. We used 2.0, 1.5, and 1.0 standard deviations (SD) below the mean of normal controls (n = 120, age 64.1 ± 6.6) to categorize MCI and the MCI subtypes. Prognostic accuracy for dementia syndrome at follow-up was estimated. Results: Amnestic multi-domain MCI (aMCI-md) significantly predicted dementia under all conditions, most markedly when speed/attention, language, or executive function was impaired alongside memory. For aMCI-md, sensitivity increased and specificity decreased when the cut-off was lowered from 2.0 to 1.5 and 1.0 SD. Non-subtyped MCI had a high sensitivity and a low specificity. Conclusion: Our results suggest that aMCI-md is the only viable subtype for predicting dementia for both follow-up times. Lowering the cut-off decreases the positive predictive value and increases the negative predictive value of aMCI-md. The results are important for understanding the clinical prognostic utility of MCI, and MCI as a non-progressive disorder.

“…In contrast, according to Petersen et al [5], MCI is a memory impairment beyond what is expected for age and education and can be seen as the transitional stage between age-related cognitive decline and dementia, especially regarding Alzheimer disease. Besides patients with pure memory complaints (amnestic MCI), there are also patients in which memory remains intact, but one (single domain) or more (multiple domain) other cognitive abilities (e.g., language, visual-spatial skills, and executive functioning) are significantly impaired (nonamnestic MCI) [8,9,10]. Amnestic MCI is believed to cause Alzheimer disease.…”

Section: Introductionmentioning

confidence: 99%

Cognitive Impairment Is Reflected by an Increased Difference between Real and Imagined Timed Up and Go Test Performance

Ruediger

Stuckenschneider

Vogt

et al. 2017

Background: Recent research suggests using an imaginary version of the Timed Up and Go test (TUG) for a first assessment of cognitive impairment. By using the time difference between a real (TUGr) and an imagined (TUGi) TUG task, the objective of this study was to examine the effect of cognitive impairment on motor imagery ability. Methods: Fifty-two participants (mean age 69.3 ± 4.0 years) with mild cognitive impairment or subjective cognitive impairment were included in this study. The time difference between the TUGr and the TUGi was used as the main outcome. The Trail Making Test part B (TMT B), the ratio between TMT A and TMT B, and the Montreal Cognitive Assessment (MoCA) battery were the main independent variables. Results: The difference between TUGr and TUGi performance time and the TMT B performance time increased with decreasing cognitive function (p < 0.01). There was no relationship between TUGr and TUGi performance time and TMT B/A ratio. There were significant correlations between TUG time differences and the MoCA score (r = -0.489, p < 0.01), the TMT B (r = 0.364, p < 0.01), and the TMT B/A ratio (r = 0.377, p < 0.01). Conclusion: The combination of TUGr and TUGi may have added value in assessing cognitive impairment, which is a possible pre-stage of dementia.