Neuropsychological Comparison of Patients With Alzheimer’s Disease and Dementia With Lewy Bodies
Sung Woo Kang, So Hoon Yoon, Han Kyu Na, Young‐gun Lee, Seun Jeon, Kyoungwon Baik, Young H. Sohn, Byoung Seok Ye
Abstract
Background and Purpose This study aimed to determine the neuropsychological differences between patients with early-stage Alzheimer's disease (AD) and dementia with Lewy bodies (DLB) with a Clinical Dementia Rating (CDR) score of 1. MethodsWe examined 168 patients with AD (126 with CDR score=0.5, 42 with CDR score=1) and 169 patients with DLB (104 with CDR score=0.5, 65 with CDR score=1) whose diagnoses were supported by 18 F-flobetaben positron-emission tomography (PET) and 18 F-N-(3fluoropropyl)-2-carbon ethoxy-3-(4-iodophenyl) nortropane PET.Neuropsychological test scores were compared after controlling for age, sex, and education duration.Using a cutoff motor score on the Unified Parkinson's Disease Rating Scale of 20, patients with AD were further divided into AD with parkinsonism (AD P+ , n=86) and AD without parkinsonism (AD P-, n=82).Results At CDR scores of both 0.5 and 1, the DLB group had lower scores on the attention (digit-span forward at CDR score=0.5 and backward at CDR score=1), visuospatial, and executive (color reading Stroop test at CDR score=0.5 and phonemic fluency test, Stroop tests, and digit symbol coding at CDR score=1) tests than the AD group, but higher scores on the memory tests.The AD P-and AD P+ subgroups had comparable scores on most neuropsychological tests, but the AD P+ subgroup had lower scores on the color reading Stroop test.Conclusions Patients with DLB had worse attention, visuospatial, and executive functions but better memory function than patients with AD.Parkinsonism was not uncommon in the patients with AD and could be related to attention and executive dysfunction.