title: Utility of testing for apraxia and associated features in dementia.
abstract: BACKGROUND
  Existing literature suggests that the presence or absence of apraxia and associated parietal deficits may be clinically relevant in differential diagnosis of dementia syndromes.
  
  
  OBJECTIVE
  This study investigated the profile of these features in Alzheimer's disease (AD) and frontotemporal dementia (FTD) spectrum disorders, at first presentation.
  
  
  METHODS
  Retrospective case note analysis was undertaken in 111 patients who presented to the Oxford Cognitive Disorders Clinic, Oxford, UK, including 29 amnestic AD, 12 posterior cortical atrophy (PCA), 12 logopenic primary progressive aphasia (lvPPA), 20 behavioural variant FTD (bvFTD), 7 non-fluent variant PPA (nfvPPA), 6 semantic variant PPA (svPPA) and 25 patients with subjective cognitive impairment (SCI). The clinical features of interest were: limb apraxia, apraxia of speech (AOS), and left parietal symptoms of dyslexia, dysgraphia, and dyscalculia.
  
  
  RESULTS
  The prevalence of limb apraxia was highest in PCA, amnestic AD, lvPPA and nfvPPA. AOS was only observed in nfvPPA. Associated parietal features were more prevalent in AD spectrum than FTD spectrum disorders. Group comparisons between key differential diagnostic challenges showed that lvPPA and nfvPPA could be significantly differentiated on the presence of left parietal features and AOS, and amnestic AD could be differentiated from bvFTD, svPPA and SCI by limb apraxia. Regression analysis showed that limb apraxia could successfully differentiate between AD and FTLD spectrum disorders with 83% accuracy.
  
  
  CONCLUSIONS
  Disease-specific profiles of limb apraxia and associated deficits can be observed. FTD and AD spectrum disorders can be difficult to differentiate due to overlapping cognitive symptoms, and measures of apraxia, in particular, appear to be a promising discriminator.
authors.affiliation: Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, UK.
authors.forename: Samrah
authors.initials: S
authors.lastname: Ahmed
authors.affiliation: Russell Cairns Unit, Oxford University Hospitals NHS Trust, John Radcliffe Hospital, Oxford, UK.
authors.forename: Ian
authors.initials: I
authors.lastname: Baker
authors.affiliation: Department of Clinical Neurology, Oxford University Hospitals NHS Trust, Oxford, UK.
authors.forename: Sian
authors.initials: S
authors.lastname: Thompson
authors.affiliation: Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, UK Department of Experimental Psychology, University of Oxford, John Radcliffe Hospital, Oxford, UK.
authors.forename: Masud
authors.initials: M
authors.lastname: Husain
authors.affiliation: Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, UK.
authors.forename: Christopher R
authors.initials: CR
authors.lastname: Butler
mesh_terms: D000368:Aged; D000544:Alzheimer Disease / Q000175:diagnosis*; D001072:Apraxias / Q000145:classification / Q000175:diagnosis*; D003937:Diagnosis, Differential; D005260:Female; D005500:Follow-Up Studies; D057180:Frontotemporal Dementia / Q000175:diagnosis*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies