title: Can clock drawing differentiate Alzheimer's disease from other dementias?
abstract: BACKGROUND
  Studies have shown the clock-drawing test (CDT) to be a useful screening test that differentiates between normal, elderly populations, and those diagnosed with dementia. However, the results of studies which have looked at the utility of the CDT to help differentiate Alzheimer's disease (AD) from other dementias have been conflicting. The purpose of this study was to explore the utility of the CDT in discriminating between patients with AD and other types of dementia.
  
  
  METHODS
  A review was conducted using MEDLINE, PsycINFO, and Embase. Search terms included clock drawing or CLOX and dementia or Parkinson's Disease or AD or dementia with Lewy bodies (DLB) or vascular dementia (VaD).
  
  
  RESULTS
  Twenty studies were included. In most of the studies, no significant differences were found in quantitative CDT scores between AD and VaD, DLB, and Parkinson's disease dementia (PDD) patients. However, frontotemporal dementia (FTD) patients consistently scored higher on the CDT than AD patients. Qualitative analyses of errors differentiated AD from other types of dementia.
  
  
  CONCLUSIONS
  Overall, the CDT score may be useful in distinguishing between AD and FTD patients, but shows limited value in differentiating between AD and VaD, DLB, and PDD. Qualitative analysis of the type of CDT errors may be a useful adjunct in the differential diagnosis of the types of dementias.
authors.affiliation: Department of Psychiatry,Sunnybrook Health Sciences Centre,Canada;Department of Psychological Medicine,Tan Tock Seng Hospital,Singapore.
authors.forename: Lynnette Pei Lin
authors.initials: LP
authors.lastname: Tan
authors.affiliation: Division of Geriatric Psychiatry,Department of Psychiatry,Sunnybrook Health Sciences Centre,Canada;Department of Psychiatry,University of Toronto,Canada.
authors.forename: Nathan
authors.initials: N
authors.lastname: Herrmann
authors.affiliation: Department of Psychology,Ryerson University,Toronto,Canada.
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Mainland
authors.affiliation: Sunnybrook Health Sciences Centre,Canada;Department of Psychiatry,University of Toronto,Canada.
authors.forename: Kenneth
authors.initials: K
authors.lastname: Shulman
mesh_terms: D000544:Alzheimer Disease / Q000175:diagnosis*; D015140:Dementia, Vascular / Q000175:diagnosis*; D003937:Diagnosis, Differential; D057180:Frontotemporal Dementia / Q000175:diagnosis*; D006801:Humans; D020961:Lewy Body Disease / Q000175:diagnosis*; D008403:Mass Screening; D010300:Parkinson Disease / Q000175:diagnosis*; D011569:Psychiatric Status Rating Scales
keywords: Alzheimer’s disease; Parkinson’s dementia; clock-drawing test; dementia with Lewy bodies; frontotemporal dementia; vascular dementia