Neuropsychological Impairments and their cognitive architecture in Mild Cognitive Impairment (MCI) with Lewy Bodies and MCI-Alzheimer’s Disease

This is the final version. Available on open access from Cambridge University Press via the DOI in this recordObjective: 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-AD (n=39) were diagnosed following National Institute on Aging-Alzheimer’s Association (NIA-AA) and 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=0.03, g=0.45; Digit Symbol Substitution Test [DSST]: p=0.04, g=0.47; DSST Error Check: p.05) Conclusions: MCI-LB was characterised by executive dysfunction and slowed processing speed but did not show the visuospatial dysfunction expected, whilst MCI-AD displayed an amnestic profile. However, there was considerable neuropsychological profile overlap and processing speed mediated performance in both MCI subtypes.Alzheimer’s Research UKMedical Research Council (MRC)GE HealthcareAlzheimer’s SocietyNational Institute for Health Research (NIHR