title: A study on variability of quantitative sensory testing in healthy participants and painful temporomandibular disorder patients.
abstract: OBJECTIVE
  Quantitative sensory testing has mainly used thresholds to evaluate somatosensory sensitivity so far. The variability of different measures from session to session has also been investigated, but the variability of the single individual measures of a threshold or subject-based reports has not been considered. This study aimed to investigate the potential value of threshold variability in one session as a measure of internal consistency in somatosensory function.
  
  
  METHODS
  The standardized quantitative sensory testing battery developed by the German Research Network on Neuropathic Pain was performed bilaterally over the infraorbital, mental, and hand regions in 70 healthy and 22 temporomandibular disorder pain participants. Somatosensory variability was investigated by calculating the Coefficient of Variation of three to five repeated measures in one threshold determination. The influences of side, gender, site, age, and presence of pain on the somatosensory variability were evaluated.
  
  
  RESULTS
  In the healthy participants, somatosensory variability was region dependent: hand > mental and/or infraorbital for CDT, WDT, HPT, MDT-N, MPT-Y, MPT-N, WUR, and MPS (p ≤ 0.043), infraorbital > hand for VDT (p = 0.001), mental > infraorbital for HPT and WUR (p ≤ 0.001); and age dependent for WDT, TSL, CPT, HPT, MDT-Y, MDT-N, MPT-N, and WUR (p ≤ 0.017). Gender and side had no main effect on variability (p ≥ 0.136). The pain patients presented higher variability compared with healthy participants for TSL, MDT-N, MPT-Y, WUR, and PPT (p ≤ 0.033).
  
  
  CONCLUSIONS
  The somatosensory variability along with the threshold would be a more complete method to investigate the somatosensory disorders and underlying pain mechanisms. The correlation between pain duration and somatosensory variability should be studied further with different pain conditions.
authors.affiliation: Department of Prosthodontics and Center for Oral Functional Diagnosis, Treatment and Research, Peking University School of Stomatology , Beijing , China .
authors.forename: Guangju
authors.initials: G
authors.lastname: Yang
authors.forename: Lene
authors.initials: L
authors.lastname: Baad-Hansen
authors.forename: Kelun
authors.initials: K
authors.lastname: Wang
authors.forename: Qiu-Fei
authors.initials: QF
authors.lastname: Xie
authors.forename: Peter
authors.initials: P
authors.lastname: Svensson
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D017288:Pain Threshold / Q000502:physiology*; D010812:Physical Stimulation; D012684:Sensory Thresholds / Q000502:physiology*; D017603:Signal Detection, Psychological / Q000502:physiology*; D013705:Temporomandibular Joint Disorders / Q000503:physiopathology*; D014732:Vibration; D055815:Young Adult
keywords: Coefficient of Variation; Quantitative sensory testing; somatosensory variability; temporomandibular disorder