Quantitative examination of taste deficiency due to radiation therapy

A study was carried out with a Rion TR-03 type electro-gustometer for subjective and quantitative expression of the degree of taste deficiency due to radiation therapy and the effects of treatment. The changes of the electro-gustometric threshold due to irradiation were examined in patients who were divided into three groups: those receiving irradiation of the whole oral cavity, those receiving irradiation of the posterior tongue and the soft palate and those receiving irradiation of the gustatory nervous system. In the group receiving irradiation of the whole oral cavity, the threshold showed a tendency to increase when receiving 10 Gy/5 days, and the threshold became unmeasurable when more than 40 Gy/26 days was given. In the group receiving irradiation of the posterior tongue and the soft palate, almost no change of the threshold in the anterior was observed in spite of increasing irradiation doses. In the group receiving irradiation of the gustatory nervous system, the threshold in the intact hemicephalus did not changed even after irradiation, but a change was found on the pathological side. Based on these results, the authors originated a complication scoring system and a treatment scoring system both of which are divided into five stages. An electro-gustometric examination is used in order to provide effective treatment with a preserving function something which has been strongly desired for radiation therapy of cancer.