Neurological assessment using quantitative sensory test in patient with chronic orofacial pain

Orofacial pain is a challenging problem for the clinician to diagnose and treat and there is little information on the etiology of this condition. The recently developed Quantitative Sensory Testing methods (QST) offer a number of potential tools for the diagnosis and etiological assessment of orofacial pain. \nThe aim of the study was to evaluate responses to thermal stimuli in subjects with different types of orofacial pain using QST. Specifically the response within subjects with these pains between painful and non-painful facial sites \nEighty five adult (30-84 year) diagnosed with different types of orofacial pain were recruited. Sixty of them with unilateral pain were subjected to QST with a neuro-sensory analyser (TSA II 100) to investigate the differences in thermal stimuli (Cold Sensation (CS), Warm Sensation (WS), Cold Pain (CP) and Hot Pain (HP)) between the pain side and the non-pain side. A mini thermode was placed on the area of pain of the painful side and on symmetrical non-pain area. The mean value of a set of experiments (3-5 trials for each modality (i.e. CS, WS, CP and HP)) was calculated and a t test statistical analysis was performed. A p value of less than 0.05 was considered significant. \nThe results indicate that patients with unilateral orofacial pain conditions were more sensitive to cold stimuli and less sensitive to heat stimuli on the pain side. When dividing them into neuropathic pain group and temporomandibular disorders pain group, the results showed that the pattern of QST response towards the four modalities (CS, WS, CP and HP) was different from the original pain group and was also different between the two groups. This suggests that neurosensory mechanisms in patients with different types of orofacial pain conditions are not the same. \nThe study confirms that a QST investigation allows a quick, non-invasive method, to assess the quantitative function and dysfunction of small fibres and nociceptive pathways in orofacial pain conditions.