Tadahiko Yuji

A fully automated health-care monitoring at home without attachment of any biological sensors and its clinical evaluation

Daily monitoring of health condition is important for an effective scheme for early diagnosis, treatment and prevention of lifestyle-related diseases such as adiposis, diabetes, cardiovascular diseases and other diseases. Commercially available devices for health care monitoring at home are cumbersome in terms of self-attachment of biological sensors and self-operation of the devices. From this viewpoint, we have been developing a non-conscious physiological monitor installed in a bath, a lavatory, and a bed for home health care and evaluated its measurement accuracy by simultaneous recordings of a biological sensors directly attached to the body surface. In order to investigate its applicability to health condition monitoring, we have further developed a new monitoring system which can automatically monitor and store the health condition data. In this study, by evaluation on 3 patients with cardiac infarct or sleep apnea syndrome, patients’ health condition such as body and excretion weight in the toilet and apnea and hypopnea during sleeping were successfully monitored, indicating that the system appears useful for monitoring the health condition during daily living.

Dysfunctional Cortical Connectivity During the Auditory Oddball Task in Patients with Schizophrenia

Background: We studied the imaginary coherence (IC) of gamma frequency oscillations between brain regions of male schizophrenia patients during an auditory oddball task using magnetoencephalography (MEG) and electroencephalography (EEG). Methods: Subjects were 10 right-handed male schizophrenia patients, evaluated by the positive and negative symptom scale (PANSS), and 10 healthy controls. Functional connectivity during the auditory oddball task was reconstructed in low (30-50 Hz) and high (50-100 Hz) gamma bands, and represented by imaginary coherence (IC) based on significant oscillatory power changes. We calculated correlations between PANSS scores and IC. Results: In the high gamma band, IC between left occipital and right prefrontal lobe areas during the time window 750-1000 ms from stimulus onset showed negative correlations with total negative scores, total positive scores, the sum of positive and negative scores in PANSS, conceptual disorganization, and social avoidance scores. In the low gamma band, IC between the same areas from 250-500 ms also showed a negative correlation with the conceptual disorganization score. In the same time window, IC between left occipital and right frontoparietal lobe areas in the low gamma band showed a positive correlation with hallucinatory behavior; IC between right temporal pole and left prefrontal lobe areas showed a positive correlation with delusion scores, although these ICs were decreased relative to controls. Conclusions: Functional disconnection of high and low gamma bands in auditory oddball task may play an important role in the auditory processing in schizophrenia patients.

Development of a Wearable Device Capable of Monitoring Human Activity for Use in Rehabilitation and Certification of Eligibility for Long-Term Care

The importance of human posture monitoring is well recognized in the field of rehabilitation, in order to evaluate quantitatively the effectiveness of rehabilitation by a physical therapist. The activity monitoring is also well recognized as being useful in the field of certification of eligibility for long-term care. Assessment of the actual physical condition of the applicant tends to be difficult when determining the level of need for long-term care. Taking these circumstances in consideration, we attempted to measure the activities of patients in rehabilitation using a wearable device for monitoring human activity. The results clearly demonstrated that detailed motion characteristics could be detected during standing up, walking and sitting up as angle changes between specific body segments and as trunk motion acceleration

Development of a Wearable Sensor System for Monitoring Static and Dynamic Posture together with Walking Speed for Use in Rehabilitation

We have developed a wearable system for monitoring static and dynamic posture in sagittal plane together with walking speed, and reported its usefulness in the rehabilitation field. However, in the previous system, there still remain several drawbacks for practical use such as accuracy in angle measurement, cumbersome cable arrangements, and so on. In order to improve these practical drawbacks, a new sensor system was designed, and its availability was evaluated. Using 11 healthy subjects (21 to 75 yrs) and 14 patients with hemiplegia (61 to 87 yrs) under their informed consent, the measuring accuracy of the improved system was evaluated by simultaneous recordings of a digital video. The results demostrated that the accuracy of this system (angle change; r=0.997, walking speed; r=0.992) showed superior to that of the previous system (angle change; r=0.986, walking speed; r=0.960). It is clearly shown through the practical monitoring that this system appears to be a useful and significant means for quantitative assessment of the human motion during rehabilitation programs.

Development of an ambulatory device for monitoring posture change and walking speed for use in rehabilitation.

Monitoring of posture change in sagittal plane and walking speed is important for evaluate the effectiveness of rehabilitation program or brace. We have developed a wearable device for monitoring human activity. However, in the previous system, there still remain several drawbacks for practical use such as accuracy in angle measurement, cumbersome cable arrangements, and so on. In order to improve these practical drawbacks, a new sensor system was designed, and its availability was evaluated. The results demonstrated that the accuracy of this system showed superior to that of the previous, and this system appears to be a significant means for quantitative assessment of the patients motion

Monitoring rehabilitation training for hemiplegic patients by using a tri-axial accelerometer

In rehabilitation training for hemiplegic patients, bed-to-wheelchair transfer is most important and allows a patients early independence. We developed a monitoring system for transfer training that is quantitative and uses accelerometry. Two tri-axial accelerometers were attached to the subjects, at the head and waist. Subjects were trained in moving from a sitting position to standing, then turning through, about 90 degrees, and then sitting on the bed. The acceleration signals at the two sites were recorded via a multi-telemeter system, converted to a digital signal, and stored in a computer. Data were analysed by LabView and displayed on the computer screen as real time motion. The system can be operated by one staff member, and the patients did not feel restricted. We were able to evaluate the time course of the signals, and phase-plane locus of the vertical, lateral and horizontal directions of the signals. The transfer of hemiplegic patients occurred in two motions: a standing-up motion, and a sitting-down motion. Accordingly, we observed twin peaks in the plot of the original signal. In contrast, healthy volunteers moved smoothly and twin peaks were not present.

Development of a ubiquitous healthcare monitoring system combined with non-conscious and ambulatory physiological measurements and its application to medical care

The demand for ubiquitous healthcare monitoring has been increasingly raised for prevention of lifestyle-related diseases, acute life support or chronic therapies for inpatients and/or outpatients having chronic disorder and home medical care. From these view points, we developed a non-conscious healthcare monitoring system without any attachment of biological sensors and operations of devices, and an ambulatory postural changes and activities monitoring system. Furthermore in this study, in order to investigate those applicability to the ubiquitous healthcare monitoring, we have developed a new healthcare monitoring system combined with the non-conscious and the ambulatory measurements developed by us. In patients with chronic cardiovascular disease or stroke, the daily health conditions such as pulse, respiration, activities and so on, could be continuously measured in the hospital, the rehabilitation room and subjects own home, using the present system. The results demonstrated that the system appears useful for the ubiquitous healthcare monitoring not only at medical facility, but also during daily living at home.

Analysis of interaction between therapist and hemiplegic patient for control of lateral pelvic motion during robotic gait training

Robotic gait training has been introduced recently in rehabilitation, and the related researches have been conducted to propose more effective mechanism and control. To automate gait training, position control with reference trajectory has been adopted in many researches. However, there remain problems such as enhancing self-dominated gait or adapting to asymmetry or individual difference to apply robotic gait training to moderately affected hemiplegia patient. To solve this problem, we quantified the manual pelvic assistance (handling) provided by physical therapy, which can enhance patients self dominated gait individually. In this paper, the physical model of handling was proposed based on the measurement and verified by multiple regression analysis.

PC-based rehabilitation tool for the elderly

The elderly can sometimes find rehabilitation training to be very boring, but if the participants are motivated or having fun, they will continue to exercise. Prevention is the most important issue for health care insurance in Japan, and since suitable training will improve the quality of life, we developed personal computer (PC)-based rehabilitation tools to help the elderly maintain balance and muscle strength. After using the balance-training device, the subjects were able to keep better balance, and the muscle-training device resulted in an energy expenditure of around 2 METs fewer than walking. The results indicate that PC-based rehabilitation tools are effective for maintaining physical exercise.

The influence of floor material on standing and walking by hemiplegic patients

In this study, we evaluated the influence of floor materials on standing and walking in hemiplegic patients. To monitor body motion during standing and walking without any constraint, we used a measurement system that consisted of an accelerometer device, a telemeter system, and a personal computer. The posture angles in the antero-posterior and lateral directions were calculated from the low frequency component of the acceleration signal to evaluate body motion. Experiments were performed with six poststroke hemiplegic patients. We modified the time up and go test introduced by Podsiadle. The patients executed the task on three different floor materials: wooden flooring, linoleum, and carpet. The posture angle pattern on carpet differed from those on wooden flooring and linoleum. Therefore, the floor material influenced body motion. We suspect that this difference in movement corresponds to the hardness of the material.