Reliability of intraoral quantitative sensory testing (QST)

Aim The prevalence of orofacial pain is reported to be around 20%. The most common location is intraoral, including recurrent and persistent pain conditions. Clinical signs and symptoms have been reported to overlap between nociceptive and neuropathic pain conditions, leading to difficulties in differential diagnosis. Somatosensory changes are important clinical features of neuropathic pain, and a comprehensive clinical examination including orofacial as well as qualitative and quantitative somatosensory examinations has been recommended for chronic intraoral pain investigations. The German Research Network on Neuropathic Pain (DFNS) has recommended a protocol with 13 quantitative sensory testing (QST) measures for detecting somatosensory abnormalities. Reliability is an important scientific property and has been adequately tested for cutaneous QST, but not for intraoral sites. The aim of this study was to evaluate the inter-examiner and intra-examiner (test-retest) reliabilities of the DFNS protocol at intra- and extraoral trigeminal sites. Material and methods Twenty-one healthy volunteers from Malmö University, Malmö, Sweden (13 women and 8 men, mean age 40.4 years, range 24–71) participated. Two independent examiners previously trained in the DFNS QST protocol examined the participants using the entire protocol. Each participant was examined twice on the same day, once by each examiner (inter-examiner reliability). After 1–3 weeks, one examiner re-examined all participants (intra-examiner reliability). The measurements were made on the skin of the right cheek, the tip of the tongue, and bilaterally on the gingival mucosa of the upper premolar region. The intraclass correlation coefficient (ICC) or kappa was used to calculate variations. Results Most tests had acceptable to excellent inter-examiner (ICC 0.41–0.89) and intra-examiner (ICC 0.43–0.87) reliability. For each test, inter- and intra-examiner reliabilities at intra- and extraoral sites were similar. No significant differences between right and left sides were found intraorally. Conclusion We conclude that inter- and intra-examiner reliabilities of most QST measures according to the DFNS protocol are acceptable for assessing somatosensory function in the orofacial region