title: Thermal and pressure pain sensitivity in patients with unilateral shoulder pain: comparison of involved and uninvolved sides.
abstract: METHODS
  Cross-sectional.
  
  
  BACKGROUND
  In the examination of patients with unilateral shoulder pain, pain provocation testing to compare the involved and uninvolved sides has been considered useful. However, side-to-side comparisons of experimental pain sensitivity in patients with unilateral shoulder pain are not widely reported in the literature.
  
  
  OBJECTIVE
  To compare experimental pain sensitivity between the involved and uninvolved sides in patients with unilateral shoulder pain.
  
  
  METHODS
  In consecutive patients seeking operative treatment for shoulder pain, sensitivity measures of bilateral pressure pain threshold at the shoulder and forearm, and thermal pain threshold, tolerance, and temporal summation at the forearm, were examined. Pressure sensitivity was tested with a Fischer pressure algometer, and thermal sensitivity with a computer-controlled Medoc neurosensory analyzer. The involved and uninvolved sides were compared with an analysis of variance. Influence of sex and location of testing were considered as covariates in the analysis.
  
  
  RESULTS
  Fifty-nine consecutively recruited participants completed experimental pain sensitivity testing. Participants reported significantly lower pressure pain thresholds in the involved side compared to the uninvolved side (F1,56 = 4.96, P = .030). In addition, female compared to male participants demonstrated lower pressure pain thresholds in the bilateral shoulder regions (F1,56 = 10.84, P = .002). There was no difference in thermal pain sensitivity between sides. Average clinical pain intensity was negatively correlated with pressure pain threshold at the involved local site (r = -0.284, P = .029), indicating an influence of clinical pain intensity on local pressure pain.
  
  
  CONCLUSIONS
  The results of this study provide evidence for higher experimental pressure pain sensitivity in the involved side of patients with unilateral shoulder pain and no difference between sides for thermal pain sensitivity. Females demonstrated higher pain sensitivity than males to pressure stimuli at the local shoulder region but not at the distal regions. Future studies should incorporate multiple stimuli when describing the pain profile of clinical populations.
authors.affiliation: Department of Physical Therapy, University of Florida, Gainesville, FL, USA. rcoronado@phhp.ufl.edu
authors.forename: Rogelio A
authors.initials: RA
authors.lastname: Coronado
authors.forename: Lindsay L
authors.initials: LL
authors.lastname: Kindler
authors.forename: Carolina
authors.initials: C
authors.lastname: Valencia
authors.forename: Steven Z
authors.initials: SZ
authors.lastname: George
mesh_terms: D000704:Analysis of Variance; D003430:Cross-Sectional Studies; D005260:Female; D006358:Hot Temperature; D006801:Humans; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D017288:Pain Threshold; D011312:Pressure; D012737:Sex Factors; D020069:Shoulder Pain / Q000503:physiopathology*