title: Pain-associated mild sensory deficits without hyperalgesia in chronic non-neuropathic pain.
abstract: OBJECTIVE
  A mixture of sensory loss and gain is a hallmark of neuropathic pain. But hypesthesia and hyperalgesia also occur with experimentally induced acute pain. Here, we assessed sensory profiles in chronic non-neuropathic pain (osteoarthritis, OA) using the quantitative sensory testing (QST) protocol of the German Research Network on Neuropathic Pain (DFNS).
  
  
  METHODS
  Twenty individuals with OA [mean pain intensity on the numerical rating scale (NRS, 0-10): 5.6±1.5] were tested on the painful and contralateral hand and compared with 20 healthy volunteers matched for age, sex, and handedness.
  
  
  RESULTS
  In the OA group, analysis of variance revealed increased detection thresholds to tactile stimuli bilaterally and to thermal stimuli restricted to the more painful hand (all P<0.05). Pin-prick hypoalgesia was present restricted to the patients' more affected hand. Neither hyperalgesia nor allodynia was found. QST parameters were correlated with average pain intensity (r between 0.48 and 0.51).
  
  
  CONCLUSIONS
  These results suggest that chronic non-neuropathic pain may induce slight sensory impairment for large fiber function (bilateral) and small fiber function (ipsilateral). However, all changes are within the normal range, in contrast to patients with neuropathy. Inhibition of central pathways by nociceptive input and altered sensory processing due to disuse of the hand are possible mechanisms. These functional sensory alterations do not interfere with the diagnosis of neuropathy.
authors.affiliation: Department of Pain Management, Berufsgenossenschaftliches Universitätsklinikum Bergmannsheil GmbH, Bochum, Germany. andrea.westermann@ruhr-uni-bochum.de
authors.forename: Andrea
authors.initials: A
authors.lastname: Westermann
authors.forename: Anne-Kathrin
authors.initials: AK
authors.lastname: Rönnau
authors.forename: Elena
authors.initials: E
authors.lastname: Krumova
authors.forename: Sabrina
authors.initials: S
authors.lastname: Regeniter
authors.forename: Peter
authors.initials: P
authors.lastname: Schwenkreis
authors.forename: Roman
authors.initials: R
authors.lastname: Rolke
authors.forename: Rolf-Detlef
authors.initials: RD
authors.lastname: Treede
authors.forename: Helmut
authors.initials: H
authors.lastname: Richter
authors.forename: Christoph
authors.initials: C
authors.lastname: Maier
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D006233:Persons with Disabilities; D005260:Female; D006801:Humans; D006930:Hyperalgesia / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000150:complications*; D010147:Pain Measurement; D017288:Pain Threshold / Q000502:physiology*; D010812:Physical Stimulation / Q000009:adverse effects; D012678:Sensation Disorders / Q000209:etiology*; D013223:Statistics as Topic; D011795:Surveys and Questionnaires