title: The Tourette syndrome diagnostic confidence index: development and clinical associations.
abstract: BACKGROUND
  The clinical characteristics of Tourette syndrome (TS) present challenges for the systematic determination of whether individuals are affected and severity. Vocal and motor tics wax and wane, decrease over time, and may be voluntarily suppressible, and therefore may be absent at interview. Current instruments measure symptoms at interview or rate symptom severity only.
  
  
  METHODS
  To minimize error in case ascertainment and produce an instrument measuring lifetime likelihood of having had TS, clinical members of the American Tourette Syndrome Association International Genetic Collaboration developed the Diagnostic Confidence Index (DCI). The expert group worked collaboratively with progressive revision in consensus workshops using existing diagnostic criteria as guidelines. The DCI produces a score from 0 to 100 that is a measure of the likelihood of having or ever having had TS.
  
  
  RESULTS
  The DCI was administered to 280 consecutive patients with TS attending a TS clinic; 264 (94%) completed it, indicating high feasibility and acceptability. Its correlation with other instruments and associations with psychopathology provide support for its being a lifetime measure of TS.
  
  
  CONCLUSIONS
  The DCI is a useful, practicable instrument in the clinic or research practice allowing an assessment of lifetime likelihood of TS. Further work is needed to test the DCI's psychometric properties, such as its validity and reliability in populations of interest.
authors.affiliation: Department of Neuropsychiatry, Royal Free and University College Medical School, London, UK.
authors.forename: M M
authors.initials: MM
authors.lastname: Robertson
authors.forename: S
authors.initials: S
authors.lastname: Banerjee
authors.forename: R
authors.initials: R
authors.lastname: Kurlan
authors.forename: D J
authors.initials: DJ
authors.lastname: Cohen
authors.forename: J F
authors.initials: JF
authors.lastname: Leckman
authors.forename: W
authors.initials: W
authors.lastname: McMahon
authors.forename: D L
authors.initials: DL
authors.lastname: Pauls
authors.forename: P
authors.initials: P
authors.lastname: Sandor
authors.forename: B J
authors.initials: BJ
authors.lastname: van de Wetering
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D016001:Confidence Intervals; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017410:Practice Guidelines as Topic; D011569:Psychiatric Status Rating Scales / Q000706:statistics & numerical data*; D011594:Psychometrics; D005879:Tourette Syndrome / Q000145:classification / Q000175:diagnosis* / Q000235:genetics / Q000523:psychology