Nonamnestic mild cognitive impairment progresses to dementia with Lewy bodies

Abstract

Objective: To determine the rate of progression of mild cognitive impairment (MCI) to dementia with Lewy bodies (DLB). Methods:We followed 337 patients with MCI in the Mayo Alzheimer's Disease Research Center (range 2-12 years). Competing risks survival models were used to examine the rates of progression to clinically probable DLB and Alzheimer disease (AD). A subset of patients underwent neuropathologic examination.Results: In this clinical cohort, 116 remained as MCI, while 49 progressed to probable DLB, 162 progressed to clinically probable AD, and 10 progressed to other dementias. Among nonamnestic MCI, progression rate to probable DLB was 20 events per 100 person-years and to probable AD was 1.6 per 100 person-years. Among amnestic MCI, progression rate to probable AD was 17 events per 100 person-years, and to DLB was 1.5 events per 100 person-years. In 88% of those who developed probable DLB, the baseline MCI diagnosis included attention and/or visuospatial deficits. Those who developed probable DLB were more likely to have baseline daytime sleepiness and subtle parkinsonism. In 99% of the clinically probable AD group, the baseline MCI diagnosis included memory impairment. Neuropathologic confirmation was obtained in 24 of 30 of those with clinically probable AD, and in 14 of 18 of those with clinically probable DLB. Neurodegenerative conditions can evolve for many years before a threshold of neuronal loss is reached that triggers the emergence of clinical signs. Our ability to detect the earliest stage of these conditions is critical for purposes of intervening while neuronal viability is still present. Mild cognitive impairment (MCI) was initially characterized by isolated memory impairment and preserved activities of daily living. It is now well established that amnestic MCI most often represents an early stage of Alzheimer disease (AD), 1,2 with an annual rate of transition in clinical samples ranging from 10% to 17%.3-5 Although much work has been done to examine the predictive value of MCI as it relates to AD, very little is known about the predementia MCI stage of dementia with Lewy bodies (DLB).6-8 The purpose of this study was to determine the clinical characteristics of patients with MCI at increased risk of DLB, and to quantify the annual rate of progression from MCI to probable DLB in a clinical referral sample.When dementia severity is mild or mild to moderate, cognitive comparisons reveal a consistent dissociation between clinically probable AD and DLB. This is characterized by early memory and naming deficits with relatively preserved attention and visuospatial skills in AD, and impaired attention and visuospatial skills with better memory and naming in DLB. [9][10][11] We From the Departments of Psychiatry and Psychology (T

New Perspectives in the Search for Reliable Prediction of Demen tia with Lewy Bodies

“…He strongly supported the belief that RBD, when diagnosed by Polysomnogram, might be the strongest risk factor for DLB when compared with other signs [6,7]. In a study of patients with non-amnestic mild cognitive impairment (MCI) who progressed to DLB a year later, about half of the patients had RBD which was more common than two other features of DLB, Visual Hallucinations and Parkinsonism [8].…”

IC‐02‐05: Hippocampal volumes predict risk of dementia with lewy bodies in mild cognitive impairment

“…3,4 We have previously demonstrated that the competing risk of progression to probable DLB vs AD is higher in patients with nonamnestic MCI compared to amnestic MCI. 5 Hippocampal volumes on antemortem MRI are preserved in patients with DLB who have little or no additional AD pathology at autopsy. [6][7][8] Hippocampal volumes are lower in patients with DLB with increasing Braak neurofibrillary tangle stage regardless of the severity of Lewy body disease pathology.…”

“…Impairment in nonamnestic cognitive domains, particularly in the attention and visual-spatial processing domains, increases the risk for probable DLB in MCI. 4,5,23 While nonamnestic MCI is characterized by relative preservation of hippocampal volumes, hippocampal atrophy may be present in some patients with nonamnestic MCI. 22 Furthermore, hippocampal atrophy is common in patients with multiple-domain amnestic MCI, and these patients are at risk for both probable DLB and AD dementia.…”

“…22 Furthermore, hippocampal atrophy is common in patients with multiple-domain amnestic MCI, and these patients are at risk for both probable DLB and AD dementia. 3,5,20,23 Thus, the distinction of patients with MCI who will progress to DLB vs AD dementia may not be clear only by the MCI subtype. Data from the current study suggest that hippocampal volumes predict progression to probable DLB along with the MCI subtype.…”

An Integrated Neuroimaging Approach for the Prediction and Analysis of Alzheimer’s Disease and its Prodromal Stages

“…More specifically, this could help in predicting the conversion of MCI as has been reported by Ferman et al that naMCIs were more likely to develop dementia with Lewy body (DLB) while patients with aMCI are more likely to convert to AD (Ferman, et al, 2013).…”