Neuropsychological Impairments and Their Cognitive Architecture in Mild Cognitive Impairment (MCI) with Lewy Bodies and MCI-Alzheimer’s Disease

Abstract

Objective: The present study aimed to clarify the neuropsychological profile of the emergent diagnostic category of Mild Cognitive Impairment with Lewy bodies (MCI-LB) and determine whether domain-specific impairments such as in memory were related to deficits in domain-general cognitive processes (executive function or processing speed). Method: Patients (n = 83) and healthy age- and sex-matched controls (n = 34) underwent clinical and imaging assessments. Probable MCI-LB (n = 44) and MCI-Alzheimer’s disease (AD) (n = 39) were diagnosed following National Institute on Aging-Alzheimer’s Association (NIA-AA) and dementia with Lewy bodies (DLB) consortium criteria. Neuropsychological measures included cognitive and psychomotor speed, executive function, working memory, and verbal and visuospatial recall. Results: MCI-LB scored significantly lower than MCI-AD on processing speed [Trail Making Test B: p = .03, g = .45; Digit Symbol Substitution Test (DSST): p = .04, g = .47; DSST Error Check: p < .001, g = .68] and executive function [Trail Making Test Ratio (A/B): p = .04, g = .52] tasks. MCI-AD performed worse than MCI-LB on memory tasks, specifically visuospatial (Modified Taylor Complex Figure: p = .01, g = .46) and verbal (Rey Auditory Verbal Learning Test: p = .04, g = .42) delayed recall measures. Stepwise discriminant analysis correctly classified the subtype in 65.1% of MCI patients (72.7% specificity, 56.4% sensitivity). Processing speed accounted for more group-associated variance in visuospatial and verbal memory in both MCI subtypes than executive function, while no significant relationships between measures were observed in controls (all ps > .05) Conclusions: MCI-LB was characterized by executive dysfunction and slowed processing speed but did not show the visuospatial dysfunction expected, while MCI-AD displayed an amnestic profile. However, there was considerable neuropsychological profile overlap and processing speed mediated performance in both MCI subtypes.

Predicting conversion to Alzheimer’s disease in individuals with Mild Cognitive Impairment using clinically transferable features

“…This may indicate that these patients would be diagnosed with AD in a longer time perspective. Together with the most severe impairment in the group correctly allocated to the cAD group, the results gave some support to include impairment of EF processes as prodromal symptoms of AD 30 , even when a patient originally was defined within the 31 , and that other fractions may be more specific to other neurodegenerative diseases (see e.g., 32 ). The highest number of APOE positive subjects were recognised in the true and false positive subgroups, in line with conclusions from previous studies [9][10][11] .…”

“…Together with the most severe impairment in the group correctly allocated to the cAD group, the results gave some support to include impairment of EF processes as prodromal symptoms of AD 30 , even when a patient originally was defined within the amnestic subgroup of MCI. It must, however, be underscored that a test of EF selected for the present study—the B version of the Trail Making Test—assesses only a fraction of the cognitive processes involved in EF 31 , and that other fractions may be more specific to other neurodegenerative diseases (see e.g., 32 ). The highest number of APOE positive subjects were recognised in the true and false positive subgroups, in line with conclusions from previous studies 9 – 11 .…”

Patterns of structure-function association in normal aging and in Alzheimer's disease: Screening for mild cognitive impairment and dementia with ML regression and classification models

“…5. DSST identifies early stages of dementia (Proust-Lima et al, 2007) and MCI by detecting working memory impairment and multimodal amnesia (Ciafone et al, 2021). The test also shows significantly impaired performance in early dementia with Lewy Bodies (Botzung et al, 2019).…”

Predicting conversion to Alzheimer’s Disease in individuals with Mild Cognitive Impairment using clinically transferable features

“…Together with the most severe impairment in the group correctly allocated to the cAD group, the results gave some support to include impairment of EF processes as prodromal symptoms of AD 32 . It must, however, be underscored that a test of EF selected for the present study -the B version of the Trail Making Test -assesses only a fraction of the cognitive processes involved in EF 33 , and that other fractions may be more specific to other neurodegenerative diseases (see e.g., 34 ). The highest number of APOE positive subjects were recognised in the true and false positive subgroups, in line with conclusions from previous studies [10][11][12] .…”