title: Analysis of patient and proxy ratings on the Dysexecutive Questionnaire: an application of Rasch analysis.
abstract: BACKGROUND
  We provide an alternate method of analysing self-report and proxy-report data on subjective complaints of dysexecutive symptoms among a group of patients with traumatic brain injury.
  
  
  OBJECTIVE
  The purpose of this study was to examine differences in the ratings of patients and proxies on a measure of the dysexecutive syndrome and further explore the insight impairment problem in patients with traumatic brain injury.
  
  
  METHODS
  Rasch analysis was conducted on the ratings of the Dysexecutive Questionnaire (DEX) by a sample of patients and their proxies.
  
  
  RESULTS
  While the average scores based on patient and proxy ratings were approximately the same (mean patient raw score = 30.12 and mean proxy raw score = 31.32), differential item functioning was found in five DEX items. As a result, the relationship between measures obtained from patient and proxy ratings was only in the moderate range (intraclass correlation = 0.46).
  
  
  CONCLUSIONS
  Identification of differential item functioning in five of the 20 DEX items reflected the different perspectives of patients and their proxies in reporting the frequency of dysexecutive behaviour and suggests that these ratings are not interchangeable.
authors.affiliation: Neuropsychology and Applied Cognitive Neuroscience Laboratory, Institute of Psychology, Chinese Academy of Sciences, Beijing, China. rckchan@psych.ac.cn
authors.forename: R C K
authors.initials: RC
authors.lastname: Chan
authors.forename: R K
authors.initials: RK
authors.lastname: Bode
mesh_terms: D000328:Adult; D001930:Brain Injuries / Q000150:complications; D003072:Cognition Disorders / Q000175:diagnosis* / Q000453:epidemiology* / Q000209:etiology; D003627:Data Interpretation, Statistical; D005260:Female; D006801:Humans; D008297:Male; D015588:Observer Variation; D019727:Proxy; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires