Characteristics of mild cognitive impairment tending to convert into Alzheimer's disease or dementia with Lewy bodies: A follow-up study in a memory clinic

Abstract

Aim: To determine characteristics of MCI that can predict whether patients will go on to develop AD or DLB.

Methods: Ninety-three patients diagnosed with MCI underwent neuropsychological and neuroimaging examinations, and were followed-up for a mean of 44.9±19.3months. They were divided into four MCI subtypes (amnestic/non-amnestic MCI, single/multiple domain) according to neuropsychological findings, and into three other MCI categories (AD-type PET, DLB-type PET, and unknown-type PET) based on (18)F-fluorodeoxyglucose PET findings. Patients who were eventually diagnosed with AD, DLB, other dementia, or remained MCI were analyzed in relation to the groups to which they had initially been allocated at the MCI stage.

Results: Clinical diagnosis after follow-up determined AD in 21 patients (22.6%), DLB in 12 patients (12.9%), other dementia in 2 patients (2.2%), and non-converter in 58 patients (62.3%). Amnestic single-domain MCI and AD-type PET tended to convert into AD. Amnestic multiple-domain MCI and DLB-type PET tended to convert into DLB. A few patients with AD-type PET later developed DLB, and some with DLB-type PET later developed AD.

Conclusions: Predicting which type of dementia a person with MCI will later develop might be possible based on early assessment with clinical symptoms in conjunction with neuropsychological and (18)F-fluorodeoxyglucose PET findings.

Keywords: (18)F-fluorodeoxyglucose PET; Alzheimer's disease; Cingulate island sign; Dementia with Lewy bodies; Mild cognitive impairment; Primary visual cortex.