title: The dementia cognitive fluctuation scale, a new psychometric test for clinicians to identify cognitive fluctuations in people with dementia.
abstract: OBJECTIVE
  Cognitive fluctuation (CF) is a common feature of dementia and a core diagnostic symptom for dementia with Lewy bodies (DLB). CF remains difficult to accurately and reliably detect clinically. This study aimed to develop a psychometric test that could be used by clinicians to facilitate the identification of CF and improve the recognition and diagnosis of DLB and Parkinson disease, and to improve differential diagnosis of other dementias.
  
  
  METHODS
  We compiled a 17-item psychometric test for identifying CF and applied this measure in a cross-sectional design. Participants were recruited from the North East of England, and assessments were made in individuals' homes. We recruited people with four subtypes of dementia and a healthy comparison group, and all subjects were administered this pilot scale together with other standard ratings. The psychometric properties of the scale were examined with exploratory factor analysis. We also examined the ability of individual items to identify CF to discriminate between dementia subtypes. The sensitivity and specificity of discriminating items were explored along with validity and reliability analyses.
  
  
  RESULTS
  Participants comprised 32 comparison subjects, 30 people with Alzheimer disease, 30 with vascular dementia, 29 with DLB, and 32 with dementia associated with Parkinson disease. Four items significantly discriminated between dementia groups and showed good levels of sensitivity (range: 78.6%-80.3%) and specificity (range: 73.9%-79.3%). The scale had very good levels of test-retest (Cronbach's alpha: 0.82) and interrater (0.81) reliabilities. The four items loaded onto three different factors. These items were: 1) marked differences in functioning during the daytime; 2) daytime somnolence; 3) daytime drowsiness; and 4) altered levels of consciousness during the day.
  
  
  CONCLUSIONS
  We identified four items that provide valid, sensitive, and specific questions for reliably identifying CF and distinguishing the Lewy body dementias from other major causes of dementia (Alzheimer disease and vascular dementia).
authors: Biomedical Research Building, Institute for Ageing and Health, Newcastle University, Campus for Ageing and Vitality, Newcastle upon Tyne, United Kingdom.
authors: David R
authors: DR
authors: Lee
authors: Biomedical Research Building, Institute for Ageing and Health, Newcastle University, Campus for Ageing and Vitality, Newcastle upon Tyne, United Kingdom.
authors: Ian
authors: I
authors: McKeith
authors: Department of Old Age Psychiatry, University Hospital of Psychiatry, University of Bern, Bern, Switzerland.
authors: Urs
authors: U
authors: Mosimann
authors: Biomedical Research Building, Institute for Ageing and Health, Newcastle University, Campus for Ageing and Vitality, Newcastle upon Tyne, United Kingdom.
authors: Arunima
authors: A
authors: Ghosh-Nodial
authors: Biomedical Research Building, Institute for Ageing and Health, Newcastle University, Campus for Ageing and Vitality, Newcastle upon Tyne, United Kingdom.
authors: Louise
authors: L
authors: Grayson
authors: Biomedical Research Building, Institute for Ageing and Health, Newcastle University, Campus for Ageing and Vitality, Newcastle upon Tyne, United Kingdom.
authors: Barbara
authors: B
authors: Wilson
authors: Biomedical Research Building, Institute for Ageing and Health, Newcastle University, Campus for Ageing and Vitality, Newcastle upon Tyne, United Kingdom. Electronic address: alan.thomas@newcastle.ac.uk.
authors: Alan J
authors: AJ
authors: Thomas
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D003071:Cognition; D003430:Cross-Sectional Studies; D003704:Dementia / Q000175:diagnosis* / Q000523:psychology*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D020961:Lewy Body Disease / Q000175:diagnosis / Q000523:psychology; D008297:Male; D009483:Neuropsychological Tests; D010300:Parkinson Disease / Q000175:diagnosis; D011237:Predictive Value of Tests; D011594:Psychometrics; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
keywords: Cognitive fluctuation; Lewy body; dementia; psychometric