title: Infrared-monitored cold response in the assessment of Raynaud's phenomenon.
abstract: BACKGROUND
  Evaluation of treatments for Raynaud's phenomenon (RP) requires objective response parameters in addition to clinical activity scores. Thermographic monitoring of fingertip re-warming after cold challenge has been widely used but usually requires sophisticated equipment. We have previously shown that fingertip re-warming after cold challenge follows a first-order transient response curve that can be described by a single variable, designated tau.
  
  
  OBJECTIVE
  Here, we describe a novel device termed a duosensor, which records the tau value upon cold challenge in an automated manner.
  
  
  METHODS
  We determined tau values in healthy probands, patients with primary or secondary RP associated with autoimmune disease and patients with scleroderma-associated RP following cold challenge, to determine assay variability, sensitivity and specificity.
  
  
  RESULTS
  Duosensor-based thermography exhibited low intraindividual variability in healthy probands. As expected, tau values in RP patients were significantly increased compared with controls (8.08 +/- 3.65 min vs. 3.23 +/- 1.65 min). The duosensor-determined tau value yielded a specificity of 94.6% and predictive value of 95.3% for the presence of RP in a retrospective analysis of 139 patients. Furthermore, in a cohort of scleroderma patients with RP, patient self-assessment of RP severity correlated with tau values.
  
  
  CONCLUSIONS
  Taken together, the present data suggest that tau value determination provides a suitable outcome measure for clinical studies of novel RP treatments. As the duosensor is a simple stand-alone device requiring no supporting equipment and minimal personnel attention, it should allow RP activity monitoring even in clinical settings with minimal technical infrastructure.
authors.affiliation: Clinic for Dermatology, Charité, Berlin, Germany. john.foerster@charite.de
authors.forename: J
authors.initials: J
authors.lastname: Foerster
authors.forename: S
authors.initials: S
authors.lastname: Wittstock
authors.forename: S
authors.initials: S
authors.lastname: Fleischanderl
authors.forename: A
authors.initials: A
authors.lastname: Storch
authors.forename: G
authors.initials: G
authors.lastname: Riemekasten
authors.forename: O
authors.initials: O
authors.lastname: Hochmuth
authors.forename: B
authors.initials: B
authors.lastname: Meffert
authors.forename: H
authors.initials: H
authors.lastname: Meffert
authors.forename: M
authors.initials: M
authors.lastname: Worm
mesh_terms: D001831:Body Temperature / Q000502:physiology; D015331:Cohort Studies; D003080:Cold Temperature; D005385:Fingers / Q000503:physiopathology*; D006801:Humans; D007259:Infrared Rays; D010991:Plethysmography / Q000295:instrumentation / Q000379:methods; D011237:Predictive Value of Tests; D011928:Raynaud Disease / Q000175:diagnosis* / Q000503:physiopathology; D012039:Regional Blood Flow / Q000502:physiology; D012189:Retrospective Studies; D012595:Scleroderma, Systemic / Q000175:diagnosis / Q000503:physiopathology; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D013817:Thermography / Q000379:methods