In this study, we evaluated the mental stress due to corner entry speed while riding a mobility scooter by measuring skin conductance. A mobility scooter is a four-wheel electric wheelchair with a steering bar-handle. These scooters, known as “senior cars” in Japan, are generally sold for use by elderly people. Some of these scooters have a system that automatically reduces their speed to approximately 70% of the maximum depending on the steering angle at corners. However, because of mismatch with the intention of the driver, the preset deceleration rate may be uncomfortable for the driver. With the objective of providing appropriate assistance without any discomfort in such circumstances, we evaluated the mental stress of the driver. Skin conductance (SC) is one index for measuring mental sweating related to sympathetic nerve activity. First, we modified a commercially available mobility scooter for use as an experimental scooter such that it can be controlled using an external personal computer. Then, we measured SC in a task that involved turning right into a corner at a constant speed using the experimental scooter, and evaluated the mental stress due to the corner entry speed. A positive correlation between the amplitude of SC and entry speed was obtained. Further, the results of a questionnaire used to evaluate the ride discomfort after each experimental task indicated that “No Fear” and “Safety” decreased as the speed increased. As these results are consistent with the measurement results of the SC amplitude, we concluded that fear due to corner entry speed can be evaluated using SC.

Currently, visually impaired people find it difficult to use mobility support facilities because they depend on properties of the ambient environment, such as ambient sound and snow cover. Furthermore, people who became visually impaired in later life also find it difficult to use these facilities. Therefore, in this study, we aimed to develop a walking guidance system, using three-dimensional (3D) sound, that is not influenced by the surrounding environment and is easy to use. We verified the characteristics of the guidance sound produced by 3D sound. This system was implemented with a head-mounted display that is capable of producing 3D sound. In a visual restriction environment, blindfolded participants were asked to indicate toward a real or 3D guiding sound with two conditions: with head fixed or free, and using a tweet-like or water sound. We also collected subjective evaluations of the sounds. As a result, we found that a stationary sound including frequency components in a wide band, like a water sound, was able to be localized with a higher accuracy than a tweet-like sound, and was suitable as a guidance sound, according to subjective evaluations.

Fragrance influences the psychophysiological state of a person; the volume of fingertip plethysmography is consequently affected by the aspiration of aroma. Further, it may be uncomfortable depending on the amount of odor that you inhales. In this study, to observe changes in emotions during aroma aspiration, the flow of scent was continuously directed into the nose of participants quantitatively and directly. Subsequently, the stimulation threshold during aroma inhalation and change in emotions were evaluated through a questionnaire and fingertip plethysmography. We developed a fragrance generator to ensure quantitative aroma flow and participants were asked to subjectively evaluate aroma intensity and the level of comfort in real time. The results confirmed the chaotic nature of the time series data of fingertip plethysmographs. Moreover, it was confirmed that the Largest Lyapunov Exponent (LLE), which provides an indication of the amount of fluctuation, corresponds to the subjective evaluation of comfort/discomfort. The value of the index decreases during pleasure and increases during discomfort. In other words, it was confirmed that the pulse wave fluctuated when the participants were experiencing discomfort.

In the recent years, research on intelligent educational systems has attracted significant interest in exploring data from educational settings to understand learners' behavior and mental states. Hence, the means to deduce the mental state of a learner has been obtained from a variety of physiological indices. The current study aims to understand how a learner answers a question with confidence. By measuring the brain activity and eye movement by using a set of multiple-choice questions, this study analyzes the relationships between the confidence of answering the question, brain activation and eye movement at the time of answering. When there was a high confidence of answering, oxyHb tended to increase near the prefrontal cortex frontal pole and sight line movement to reread question text tended to decrease. The results show that this technique may be able to capture the mental state of the learner by measuring a combination of the change of oxyHb and sight line movement.

This study focuses on the acute influence of non-thermal alternating current (AC) electromagnetic field (EMF) exposure (50 Hz, peak magnetic flux density Bmax180 mT, 15-min duration of exposure) on blood flow velocity and electromyography (EMG) in healthy human subjects. The values of the blood flow velocity were significantly increased by the EMF exposure during and after exposure periods compared with the sham control exposure. In contrast, the mean power frequency values in EMG were not significantly changed from the baseline value in the presence of EMF exposure. These results imply that the physiological role of an EMF-enhanced blood circulation might help eliminate the metabolic waste products and endogenous pain producing substances inducing muscle stiffness and pain.

We developed a walking assistance apparatus which can be used for gait training of neuro-rehabilitation for patients and for the promotion of exercise for the elderly. This apparatus assists only the ankle joints of the equipped person according to the posture of him/her while not only walking, but also getting up, sitting, and standing. By using this apparatus, the dorsiflexion and plantarflexion of the ankle joint of the equipped person can increase while walking. This apparatus can improve of the equipped person's gait.

Methods such as the Predicted Mean Vote and Standard New Effective Temperature were developed to evaluate thermal comfort. However, radiation and convection of heat due to factors such as sunlight or air cycle are stronger in automobiles than in indoor environments. Moreover, the thermal environment in automobiles is non-uniform and locally inhomogeneous, which makes evaluating thermal comfort in automobiles difficult. We aim to evaluate the local thermal environment by analyzing brain activity. The final goal is to develop an air conditioning control system in automobiles using a brain machine interface. Herein, we describe analysis of brain activity during local hot stimulation. We measured oxyhemoglobin (oxyHb) levels in the prefrontal cortex and the primary somatosensory cortex while subjects touched aluminum plates that were heated or cooled to different temperatures. The results show that oxyHb changes in the prefrontal cortex vary according to the temperature of the aluminum plates.

Driving assist systems, which are based on biological information, have been investigated in recent years. In this paper, we measured brain activity during simulated driving using near-infrared spectroscopy. Driving is a complex behavior that requires multiple cognitive elements. Therefore, we conducted two experiments to monitor driving behavior in an unvarying road environment and a road environment including an intersection. In the first experiment, the concentration of oxygenated hemoglobin (oxy-Hb) in the prefrontal cortex changed slightly during driving in an unvarying road environment. However, oxy-Hb in the prefrontal cortex increased significantly in a situation in which the subject was unsettled by unexpected vehicle behavior. In the second experiment, oxy-Hb decreased in the prefrontal cortex during driving that required more in-depth thinking, and this decrease in oxy-Hb was associated with the complexity of thinking. Our results demonstrate that the depth of thinking during driving is responsible for changes in oxy-Hb concentration in the prefrontal cortex.

Analyses of the process of learning embodied control were carried out by observing brain activation during the learning process using near-infrared spectroscopy (NIRS) to find ways to further improve skills. Embodied knowledge is the accumulation of comprehensive learning outcomes such as experience and intuition. Fundamental knowledge is associated with operation methods of converting machineries and procedures for embodied control. Accordingly, acquired memory as an object of the analysis is procedural memory of embodied control. NIRS has the advantages of being portable, low-restraint, continuously monitorable, and it has a higher spatial resolution than other methods. In this study, analyses of brain function during embodied control and learning are reported.