title: Algometry with a clothes peg compared to an electronic pressure algometer: a randomized cross-sectional study in pain patients.
abstract: BACKGROUND
  Hypersensitivity of the central nervous system is widely present in pain patients and recognized as one of the determinants of chronic pain and disability. Electronic pressure algometry is often used to explore aspects of central hypersensitivity. We hypothesized that a simple pain provocation test with a clothes peg provides information on pain sensitivity that compares meaningfully to that obtained by a well-established electronic pressure algometer. "Clinically meaningful" was defined as a medium (r = 0.3-0.5) or high (r > 0.5) correlation coefficient according to Cohen's conventions.
  
  
  METHODS
  We tested 157 in-patients with different pain types. A calibrated clothes peg was applied for 10 seconds and patients rated the pain intensity on a 0 to 10 numerical rating scale. Pressure pain detection threshold (PPdt) and pressure pain tolerance threshold (PPtt) were measured with a standard electronic algometer. Both methods were performed on both middle fingers and ear lobes. In a subgroup of 47 patients repeatability (test-retest reliability) was calculated.
  
  
  RESULTS
  Clothes peg values correlated with PPdt values for finger testing with r = -0.54 and for earlobe testing with r = -0.55 (all p-values < 0.001). Clothes peg values also correlated with PPtt values for finger testing with r = -0.55 (p < 0.001). Test-retest reliability (repeatability) showed equally stable results for clothes peg algometry and the electronic algometer (all r-values > 0.89, all p-values < 0.001).
  
  
  CONCLUSIONS
  Information on pain sensitivity provided by a calibrated clothes peg and an established algometer correlate at a clinically meaningful level.
authors.affiliation: Department of General Internal Medicine, Division of Psychosomatic Medicine, Inselspital, Bern University Hospital, CH-3010 Bern, Switzerland. niklaus.egloff@insel.ch
authors.forename: Niklaus
authors.initials: N
authors.lastname: Egloff
authors.forename: Nicole
authors.initials: N
authors.lastname: Klingler
authors.forename: Roland
authors.initials: R
authors.lastname: von Känel
authors.forename: Rafael J A
authors.initials: RJ
authors.lastname: Cámara
authors.forename: Michele
authors.initials: M
authors.lastname: Curatolo
authors.forename: Barbara
authors.initials: B
authors.lastname: Wegmann
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Marti
authors.forename: Marie-Louise Gander
authors.initials: ML
authors.lastname: Ferrari
mesh_terms: D000328:Adult; D000368:Aged; D003430:Cross-Sectional Studies; D004568:Electrodiagnosis / Q000295:instrumentation* / Q000379:methods; D005260:Female; D006794:Household Articles / Q000295:instrumentation; D006801:Humans; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000145:classification / Q000175:diagnosis*; D010147:Pain Measurement / Q000295:instrumentation* / Q000379:methods; D017288:Pain Threshold / Q000502:physiology*; D011312:Pressure / Q000009:adverse effects*; D012680:Sensitivity and Specificity