title: Delirium subtype identification and the validation of the Delirium Rating Scale--Revised-98 (Dutch version) in hospitalized elderly patients.
abstract: BACKGROUND
  Delirium is the most common acute neuropsychiatric disorder in hospitalized elderly. The Dutch version of the Delirium Rating Scale-Revised-98 (DRS-R-98) appears to be a reliable method to classify delirium. The aim of this study was to determine the validity and reliability of the DRS-R-98 and to study clinical subtypes of delirium using the DRS-R-98.
  
  
  METHODS
  Patients received the Dutch version of the DRS-R-98, the Mini-Mental State Examination, the Confusion Assessment Method, and a clinical diagnosis of delirium according to DSM-IV criteria, and their relatives the Informant Questionnaire Cognitive Decline in the Elderly.
  
  
  RESULTS
  The DRS-R-98 validation cohort (n=65) consisted of 23 patients with delirium, 22 patients with dementia, and 20 non-psychiatric comparison patients. For the delirium subtype study, a second cohort comprising 54 delirious patients was investigated. Median DRS-R-98 scores significantly distinguished delirium from dementia and no psychiatric disorder. Inter-rater reliability (intra-class correlation 0.97) and internal consistency (Crohnbach's alpha 0.94) were high. Positive scores of DRS-R-98 item 4 (affect liability) and item 7 (motor agitation) predicted the presence of non-hypoactive delirium, with a specificity of 89% and a sensitivity of 57%.
  
  
  CONCLUSIONS
  The results show that the Dutch version of the DRS-R-98 is a valid and reliable measure of delirium severity and distinguishes patients with delirium from patients with dementia and comparison patients. Furthermore, the DRS-R-98 is able to exclude hypoactive delirium.
authors.affiliation: Department of Internal Medicine and Geriatrics, Academic Medical Center, Amsterdam, The Netherlands. s.e.derooij@amc.uva.nl
authors.forename: Sophia E
authors.initials: SE
authors.lastname: de Rooij
authors.forename: Barbara C
authors.initials: BC
authors.lastname: van Munster
authors.forename: Johanna C
authors.initials: JC
authors.lastname: Korevaar
authors.forename: Gerty
authors.initials: G
authors.lastname: Casteelen
authors.forename: Marieke J
authors.initials: MJ
authors.lastname: Schuurmans
authors.forename: Roos C
authors.initials: RC
authors.lastname: van der Mast
authors.forename: Marcel
authors.initials: M
authors.lastname: Levi
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003431:Cross-Cultural Comparison; D003693:Delirium / Q000145:classification / Q000175:diagnosis*; D003704:Dementia / Q000175:diagnosis; D003937:Diagnosis, Differential; D039721:Diagnostic and Statistical Manual of Mental Disorders; D005260:Female; D015577:Geriatric Assessment / Q000379:methods; D006801:Humans; D008297:Male; D009426:Netherlands; D011569:Psychiatric Status Rating Scales; D011594:Psychometrics; D015203:Reproducibility of Results