title: Brief assessment of delirium subtypes: Psychometric evaluation of the Delirium Motor Subtype Scale (DMSS)-4 in the intensive care setting.
abstract: The management of and prognosis for delirium are affected by its subtype: hypoactive, hyperactive, mixed, and none. The DMSS-4, an abbreviated version of the Delirium Motor Symptom Scale, is a brief instrument for the assessment of delirium subtypes. However, it has not yet been evaluated in an intensive care setting.
  
  
  
  We performed a prospective/descriptive cohort study in order to determine the internal consistency, reliability, and validity of the relevant items of the DMSS-4 versus the Delirium Rating Scale-Revised-98 (DRS-R-98) and the original DMSS in a surgical intensive care setting.
  
  
  
  A total of 289 elderly, predominantly male patients were screened for delirium, and 122 were included in our sample. The internal consistency of the DMSS-4 items was excellent (Cronbach's α = 0.92), and between the DMSS-4 and DRS-R-98 the overall concurrent validity was substantial (Cramer's V = 0.67). Within individual motor subtypes, concurrent validity remained at least substantial (Cohen's κ = 0.65-0.81) and sensitivity high (69.8 to 82.2%), in contrast to those of the no-motor subtype, with less validity and sensitivity (κ = 0.28, 22%). Similarly, total concurrent validity between the DMSS-4 and the original DMSS reached perfection (Cramer's V = 0.83), as did agreement between the subtypes (κ = 0.83-0.92), while sensitivity remained high (88.2-100%). Only in those with delirium with no-motor subtype was agreement moderate (κ = 0.56) and sensitivity lower (67%). Specificity was high across all subtypes (91.2-99.1%). The DMSS-4 yielded very sensitive ratings, particularly for hypoactive and hyperactive motor symptoms, and interrater agreement was excellent (Fleiss's κ = 0.83).
  
  
  
  We found the DMSS-4 to be a most reliable and valid brief assessment of delirium in characterizing the subtypes of delirium in an intensive care setting, with increased sensitivity to hypoactive and hyperactive motor alterations.
authors.affiliation: Department of Psychiatry and Psychotherapy,University Hospital of Zurich, University of Zurich,Zurich,Switzerland.
authors.forename: Soenke
authors.initials: S
authors.lastname: Boettger
authors.affiliation: Department of Psychiatry and Psychotherapy,University Hospital of Zurich, University of Zurich,Zurich,Switzerland.
authors.forename: David Garcia
authors.initials: DG
authors.lastname: Nuñez
authors.affiliation: Institute for Regenerative Medicine, University of Zurich,Schlieren,Switzerland.
authors.forename: Rafael
authors.initials: R
authors.lastname: Meyer
authors.affiliation: Department of Psychiatry and Psychotherapy,University Hospital of Zurich, University of Zurich,Zurich,Switzerland.
authors.forename: Andre
authors.initials: A
authors.lastname: Richter
authors.affiliation: University of Basel, University Hospital of Basel,Basel,Switzerland.
authors.forename: Maria
authors.initials: M
authors.lastname: Schubert
authors.affiliation: Graduate Entry Medical School,University of Limerick,Castletroy,Limerick,Ireland.
authors.forename: David
authors.initials: D
authors.lastname: Meagher
authors.affiliation: Department of Psychiatry and Psychotherapy,University Hospital of Zurich, University of Zurich,Zurich,Switzerland.
authors.forename: Josef
authors.initials: J
authors.lastname: Jenewein
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002983:Clinical Competence / Q000592:standards*; D015331:Cohort Studies; D003693:Delirium / Q000175:diagnosis*; D005260:Female; D006801:Humans; D007362:Intensive Care Units / Q000458:organization & administration; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011594:Psychometrics / Q000295:instrumentation / Q000379:methods* / Q000592:standards*; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D013557:Switzerland
keywords: Classification; Delirium; Delirium Motor Symptom Scale (DMSS); Delirium Rating Scale–Revised-98 (DRS–R-98); Motor subtypes