title: Olfactory function and neuropsychological profile to differentiate dementia with Lewy bodies from Alzheimer's disease in patients with mild cognitive impairment: A 5-year follow-up study.
abstract: BACKGROUND
  Mild cognitive impairment (MCI) is a well-known precursor of Alzheimer's disease (AD) but often also precedes dementia with Lewy bodies (DLB). The early differentiation of DLB from AD is important to delay disease progression. Olfactory dysfunction is a well-known early sign of both AD and Lewy body disorders, including Parkinson's disease (PD) and DLB. Thus, the aim of the present study was to determine whether olfactory and neuropsychological tests can aid in the differentiation of DLB from AD at the MCI stage.
  
  
  METHODS
  The present study included 122 MCI patients who were monitored until they developed dementia or until their condition stabilized; the follow-up period averaged 4.9 years (range: 3.9-6.2 years). Baseline olfactory function as measured with the Cross-Cultural Smell Identification (CCSI) test and neuropsychological data were compared.
  
  
  RESULTS
  During the follow-up period, 32 subjects developed probable AD (MCI-AD), 18 had probable DLB (MCI-DLB), 45 did not convert to dementia (MCI-stable), and eight developed a non-AD/DLB dementia. The mean CCSI score (95% confidence interval [CI]) in patients with MCI-DLB (4.6; 95% CI: 4.0-5.3) was significantly lower than that of MCI-AD patients (6.4; 95% CI: 6.0-6.7, p<0.001) and MCI-stable patients (7.3; 95% CI: 6.9-7.8, p<0.001). The area under the curve of the receiver operating characteristic to discriminate MCI-DLB from MCI-AD using CCSI scores was (0.84; 95% CI: 0.72-0.97). Frontal-executive function and visuospatial ability was worse in patients with MCI-DLB, while verbal recognition memory impairment was greater in those with MCI-AD.
  
  
  CONCLUSIONS
  Olfactory and neuropsychological tests can help predict conversion to DLB or AD in patients with MCI.
authors.affiliation: Department of Neurology, Ajou University School of Medicine, Suwon, South Korea. Electronic address: jhyoon@gmail.com.
authors.forename: Jung Han
authors.initials: JH
authors.lastname: Yoon
authors.affiliation: Department of Neurology, Ajou University School of Medicine, Suwon, South Korea.
authors.forename: Min
authors.initials: M
authors.lastname: Kim
authors.affiliation: Department of Neurology, Ajou University School of Medicine, Suwon, South Korea.
authors.forename: So Young
authors.initials: SY
authors.lastname: Moon
authors.affiliation: Department of Neurology, Ajou University School of Medicine, Suwon, South Korea.
authors.forename: Seok Woo
authors.initials: SW
authors.lastname: Yong
authors.affiliation: Department of Neurology, Ajou University School of Medicine, Suwon, South Korea.
authors.forename: Ji Man
authors.initials: JM
authors.lastname: Hong
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000150:complications*; D000704:Analysis of Variance; D060825:Cognitive Dysfunction / Q000175:diagnosis* / Q000209:etiology*; D003937:Diagnosis, Differential; D018450:Disease Progression; D005260:Female; D006801:Humans; D020961:Lewy Body Disease / Q000150:complications*; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D000857:Olfaction Disorders / Q000175:diagnosis* / Q000209:etiology*; D011569:Psychiatric Status Rating Scales; D012372:ROC Curve
keywords: Alzheimer's disease; Cognition; Dementia with Lewy bodies; Mild cognitive impairment; Olfaction