Hirotoki Kawasaki

Effect on electroencephalogram of chewing flavored gum.

Abstract The objective of the present study was to evaluate the effect on the electroencephalogram (EEG) of a chewing gum with and without our prepared new flavor. Electroencephalograms were obtained after the following three tests: chewing pure gumbase with sucrose (standard gumbase), chewing flavored standard gum and the inhalation of flavored aromatic oil. As the control, we used the pre‐stimulus control EEG record without a stimulus. We examined the relationship between the pre‐stimulus control record and the post‐stimulus record using the changes of power in four bands. Chewing the standard gumbase led to an increase in the alpha wave and a decrease in the beta wave. Chewing the flavored standard gum and inhaling the flavored aromatic oil each increased the alpha and beta waves. In addition, chewing the flavored standard gum led to a change in the ratio of theta wave in the frontal area. The difference in the theta, alpha and beta bands in chewing gum with and without the added flavor suggested that the flavor as well as chewing could induce concentration with a harmonious high arousal state in brain function.

Effects of three principal constituents in chewing gum on electroencephalographic activity

The effects of three principal constituents (sugar, spearmint, and gumbase) in chewing gum on EEG findings in 20 normal subjects were investigated. After they chewed the gumbase, theta activity decreased significantly at Fp2, O1, T3, T4, F4, P3, and Pz; alpha activity increased significantly at O1 and decreased significantly at Fp1, and beta activity increased significantly at Fp1, Fp2, O1, T3, T4, P3 and Pz. After they inhaled the spearmint, alpha activity decreased significantly at 02, F3, P4, and Fz, and beta increased significantly at 02, F3, P4, and Fz. The mean frequency of the alpha band was significantly higher than after 1 min at rest without inhalation. After the subjects chewed the gumbase with sucrose, theta activity increased at Fp2 and Fz; alpha activity increased significantly at T3; and beta activity decreased significantly at Fpl, Fp2, F4, P3, P4, Fz, and Pz. The mean frequency of the alpha band was significantly lower than after 1 min at rest without it at almost all the positions. These results suggest that the gumbase with sucrose induced relaxed concentration effects while inhalation of spearmint induced arousal effects. The chewing of gumbase showed arousal tendency.

Spectral analysis of changes in electroencephalographic activity after the chewing of gum

Abstract  The present study aimed to examine the psychosomatic effect in the chewing of marketed gum using eletroencephalogram (EEG) as an index. The EEG were taken in two sets: (i) a resting period before chewing (control recording) and a resting record (post‐resting recording) for examining reproducibility; and (ii) a control recording and resting period after gum‐chewing for 3 min (post‐chewing recording). The ratio of each frequency band to the total frequency power, the mean frequency of the alpha band and laterality of the frequency power was calculated. In the examination of the reproducibility, no statistically significant differences were observed between control recording and post‐resting recording in all indices. In the reflection of EEG after gum‐chewing, there were no significant differences between control recording and the post‐chewing recording. However, a significant interaction was observed among these indices by analysis of variance. In addition, the alpha power in the post‐chewing recording was significantly higher than that in the control recording at almost all the positions. In conclusion, the intra‐individual reproducibility of EEG was confirmed in the recording method. Furthermore, it was suggested that a significant interaction and a rising trend of the mean frequency of the alpha band after gum‐chewing reflected ‘arousal’ psychosomatic responses by the chewing of marketed gum.

EEG analysis of epilepsy by directed coherence method a data processing approach

Directed coherence (DCOH) was proposed in our previous work as a measure of the correlation between the EEGs of different sites of human brain. In the present research, we applied this method to the interpretation of intrahemispheric information flow in the EEGs of thirteen epileptic patients. This paper discusses the bidirectional communication pattern with DCOH between the frontal and the occipital cortex in the EEGs of epileptics. Comparing with the high values in the alpha-band for the controls, significantly (P < 0.001) small DCOH values were found in the thirteen epileptic patients. The DCOH values of epileptic patients were scattered over the beta-, theta- and delta-bands. This may suggest that the dysfunction of the epileptic brain may be due to an abnormality of the neural networks in the brain.

Nonlinear dynamical analysis of the effect by six stimuli on electroencephalogram.

The present study investigated the search by correlation dimension (D2) for the effect of six stimuli (sucrose, spearmint, gum-base chewing as a voluntary movement, and three combinations of these stimuli) on EEG findings. Twenty normal adult subjects received sucrose, spearmint oil, gum-base alone, and three combinations of these stimuli. EEG recordings were obtained while the subjects rested quietly with their eyes closed, as the following procedure: section I, 1 minute at rest; section II, first 5-minute recording (control record); session III, each stimulus affecting for 3 minutes; session IV, 1 minute at rest; session V, 5-minute recording (poststimulus record). The EEG activity was filtered with a 0.5 Hz high pass and a 30 Hz low pass filter. The final data (epoch) for analysis were selected from all data by our epoch inducing system, and D2 was calculated using a novel analytical program. D2 was found to increase after subjects inhaled spearmint. In contrast, D2 decreased after subjects chewed gum-base and after the combination stimuli with chewing. Furthermore, the D2 change observed after each stimulus was similar to the observed D2 changes in the theta band. These findings suggest that D2 expressed the change in EEG as a brain response after each stimulus. It was also demonstrated that the change of EEG complexity as a brain response to stimulation is related to theta rhythm that might be able to produce at the cortical limbic area. We confirmed that the change observed in the complexity in response to which the chewing stimulus relates in our present study is the model that best fits that theory of the change on complexity suggested by Stam CJ.