title: An increased response to experimental muscle pain is related to psychological status in women with chronic non-traumatic neck-shoulder pain.
abstract: BACKGROUND
  Neck-shoulder pain conditions, e.g., chronic trapezius myalgia, have been associated with sensory disturbances such as increased sensitivity to experimentally induced pain. This study investigated pain sensitivity in terms of bilateral pressure pain thresholds over the trapezius and tibialis anterior muscles and pain responses after a unilateral hypertonic saline infusion into the right legs tibialis anterior muscle and related those parameters to intensity and area size of the clinical pain and to psychological factors (sleeping problems, depression, anxiety, catastrophizing and fear-avoidance).
  
  
  METHODS
  Nineteen women with chronic non-traumatic neck-shoulder pain but without simultaneous anatomically widespread clinical pain (NSP) and 30 age-matched pain-free female control subjects (CON) participated in the study.
  
  
  RESULTS
  NSP had lower pressure pain thresholds over the trapezius and over the tibialis anterior muscles and experienced hypertonic saline-evoked pain in the tibialis anterior muscle to be significantly more intense and locally more widespread than CON. More intense symptoms of anxiety and depression together with a higher disability level were associated with increased pain responses to experimental pain induction and a larger area size of the clinical neck-shoulder pain at its worst.
  
  
  CONCLUSIONS
  These results indicate that central mechanisms e.g., central sensitization and altered descending control, are involved in chronic neck-shoulder pain since sensory hypersensitivity was found in areas distant to the site of clinical pain. Psychological status was found to interact with the perception, intensity, duration and distribution of induced pain (hypertonic saline) together with the spreading of clinical pain. The duration and intensity of pain correlated negatively with pressure pain thresholds.
authors: Rehabilitation Medicine, Department of Clinical and Experimental Medicine, Linköping University, SE-581 85 Linköping, Sweden.
authors: Anna
authors: A
authors: Sjörs
authors: Britt
authors: B
authors: Larsson
authors: Ann L
authors: AL
authors: Persson
authors: Björn
authors: B
authors: Gerdle
mesh_terms: D000328:Adult; D001007:Anxiety / Q000523:psychology; D058443:Catastrophization / Q000523:psychology; D003863:Depression / Q000523:psychology; D004185:Disability Evaluation; D005239:Fear / Q000523:psychology; D005260:Female; D006801:Humans; D006941:Hyperesthesia / Q000503:physiopathology* / Q000523:psychology; D008875:Middle Aged; D009334:Neck Muscles / Q000503:physiopathology*; D019547:Neck Pain / Q000503:physiopathology* / Q000523:psychology; D010147:Pain Measurement; D017288:Pain Threshold / Q000502:physiology; D020069:Shoulder Pain / Q000503:physiopathology* / Q000523:psychology; D012890:Sleep; D011795:Surveys and Questionnaires