Abstract
The purpose of this experiment was to clarify the change of brain blood flow when chewing chewing-gum using NIRS (near infrared spectroscopy).
Twenty healthy subjects in their twenties were asked to chew chewing-gum on their habitual chewing side and on their non-habitual chewing side for 1 minute respectively, and the order was random. The brain blood flow was recorded using NIRS. The measurement was performed about 7 sessions; before chewing (rest), during chewing, and 1, 2, 3, 4, and 5 minutes after chewing. Measuring probe was attached on the skin over the cortical masticatory area. The change in blood flow in the brain caused by chewing was investigated using repeated measures ANOVA. Next the amount of change in blood flow was compared between the habitual side chewing and the non-habitual side chewing using paired t-test.
The brain blood flow increased for both habitual and non-habitual chewing sides during mastication and decreased gradually after mastication and returned the condition prior to the mastication (habitual chewing side; F=127.0, non-habitual chewing side; F=92.9, p<0.01). When comparing the session prior to mastication with all the other sessions significant differences were found except with the session 5 minutes after mastication. In 18 out of 20 cases the amount of change in blood flow was larger for the habitual chewing side than for the non-habitual chewing side and a statistically significant difference was found (t = 3.78, p <0.01).
From these results it was suggested that mastication activated brain activities and that the habitual chewing side had a stronger effect than the non-habitual chewing side.
