Many patients with tongue pain are frequently found in clinics of oral medicine and surgery. There is a possibility that they include various diseases such as glossitis, tongue tumor, tongue trauma, anemia, neuralgia, oral infection, xerostomia, temporomandibular disorder, galvanism, irritant substance and glossodynia. We conducted a survey on the clinical status of 58 patients with tongue pain, and found that they consisted of 30 cases of oral candidiasis, 17 cases of oral xerostomia, 16 cases of glossodynia, 13 cases of glossitis and so on in order of prevalence. Further survey on these patients with oral candidiasis and xerostomia revealed that a large number of patients suffering from oral candidiasis had no clinical appearance in their tongues, and those of xerostomia didn't complain of thirst. Thus, because all these patients without any symptoms except for tongue pain might be diagnosed and treated as glossodynia, thorough examination such as cultivation and salivation tests should be performed in these patients. Next, we employed a novel approach to diagnose glossodynia based on heart rate variability. We examined whether or not heart rate variability reflects curative effects of linear polarized near-infrared light irradiation near stellate ganglion. The result showed that a time-dependent change of autonomic activity correlated with that of VAS value. These findings suggest that heart rate variability is useful for monitoring curative effects and estimation of prognosis
