In a present aging and stressful society, it is important to conduct a daily health check for detection of disease in early stages. Therefore, the vital sign measurements in daily life attract much attention. In this study, an electrocardiogram (ECG) acquisition system is built into a chair to measure and record ECG with clothes on. A capacitive connection between body and the system consisting of the clothes and a metal plate on a chair was used as an electrode. However, noise arising from mechanical movement of the back caused by respiration and heart beat superimposes on the ECG. Quite a large baseline wander prevents from a detailed observation of the ECG for 20 seconds or more after seating. It is difficult to remove these noises by a fixed-frequency response filter because of noise having unstable and overlapping frequency components on ECG. This study demonstrates the usefulness of adaptive filter approach for removing a movement-related noise from the signal obtained by capacitive electrodes. A separate noise-related signal required for adaptive noise canceller was measured by other capacitive electrodes simultaneously with ECG. The results indicated that the use of an adaptive noise canceller sufficiently removed the noise components in the capacitive ECG. Baseline wander was suppressed immediately after seating by noise cancellation. It is possible to detect ECG in 0.9 seconds. Although this method sufficiently removed noise, it was not yet examined if the quality of the ECG is enough for diagnosis based on such as ST segment changes because waveform was distorted by the filters in the system. As the next step, quality of the waveform must be improved to be acceptable for diagnosis by optimization of the system parameters including analog circuits. After finishing improvement, evaluation on diagnosis and long term test should be performed to show the real usefulness of capacitive ECG measurement system compensated by adaptive filter.
In the present study, we examined the lifestyles of Japanese women whose body shapes had changed in different ways over approximately 20 years. The purpose of this study was to clarify the relationship between body shape change and lifestyle by evaluating daily living based on amount of activity. Using a body shape vector, we classified 24 women in their 40s and 50s into 3 groups with different body shape changes. An experiment was conducted on weekdays for 1 week with 24 healthy women in their 40s and 50s with different body shape changes. The amount of activity of the non-dominant wrist and trunk, subjective evaluation of sleep quality, and subjective state of activity were surveyed for 1 week. For the analysis, the amount of activity was classified on a time series for weekdays during active periods, sleeping periods, and non-measurement periods (e. g., bathing) using a subjective activity state. We then evaluated subjects' activity, sleep, and variation in the pace of life. Women who had maintained the same body shape throughout life were found to have little sedentary time, high trunk movement during active periods, little activity during sleep periods, high subjective sleep scores, and a varied pace of life. In order to identify important lifestyle factors, it is necessary to evaluate the amount of activity throughout the day, including during sleep. In conclusion, the present results suggest that, compared with women who had not maintained the same body shape over 20 years, women who had maintained the same body shape had a consistently sensible diet, had little sedentary time and sustained a high level of trunk movement during the day, slept well at night, and had a varied pace of sleep-wake rhythm.
To determine the organization of the neural system involved in the cognitive process for identifying fragmented letters through visual interpolation, we used near-infrared spectroscopy to examine whether the neural activation of distinct cerebral regions with different blood flows was evoked in 13 healthy young male subjects who were asked to identify complete and fragmented letters. Fragmented letters of the English alphabet (black, 72-point, MSP Gothic) were randomly displayed one by one on the screen of a personal computer in the same method as complete letters. Each of the letters was presented within a square (128 × 128 pixels) against a white background for 1200 ms. Fragmented letters were produced by randomly removing rectangular areas (6 × 12 pixels) that, overall, comprised 90% of the pixels from complete letters. The rectangles removed were randomly rotated. The rates of correct identification in reading letters were 61 ± 7% for fragmented letters and 100% for complete letters in all subjects, which were significantly different (P < 0.05). Concentrations of oxyhemoglobin in the dorsolateral frontal gyrus [at or near Brodmann area (BA) 9], the inferior and middle frontal gyrus (at or near BA 44 and BA 45), and the lateral premotor and primary motor gyrus (at or near BA 6 and BA 4) in the right and left hemispheres were significantly (P < 0.05) greater during fragmented-letter identification than during complete-letter identification. These results demonstrated that fragmented-letter identification was accompanied by greater activation in the bilateral dorsolateral, inferior, and lateral frontal cortices, compared to complete-letter identification. However, this study could not determine any specific locus of the neural substrate that processed the visual interpolation to compensate for the lack of segments in fragmented letters or the generation of mental-imagery letters.
The long term goal of our research is to develop an in-car health screening instrument, based on a novel approach for physiological measurement, in order to contribute to much-needed efforts aimed at achieving safer driving. We describe here a feasibility study in which a system was constructed to derive cardiac indices non-invasively and simultaneously using a finger cuff. Specifically, the instrument measures blood pressure (BP), pulse rate (PR), normalized pulse volume (NPV) reflecting alpha-adrenergic sympathetic activity, and finger-artery elasticity index (FEI). The instrument's measurement process has two phases:firstly, cuff pressure is maintained at 30 mmHg to measure the NPV and PR;secondly, whilst applying a gradual change in counter-pressure, the BP and FEI are measured by application of the volume-oscillometric method. We tested a prototype instrument in 5 healthy male and female volunteers (age 21, 22, 36, 37, 49 years) during two weeks day-to-day living, including a 33-hour period of total sleep deprivation as physiological challenge. The results indicated that with sleep deprivation there appear to be relatively large physiological changes. In conclusion, the prototype system we have developed has allowed the periodic collection of physiological data in a convenient and expeditious way without any failure, demonstrating the possibility to detect an adverse effect on health. Further investigations will be needed in a larger group of subjects with a variety of real environmental conditions.
In this preliminary study, we examined in human volunteers the performance of the developed prototype device for non-invasive quantification of blood alcohol concentration (BAC) by near-infrared light which is highly transparent to the body. We aimed at applying the results to the final goal of developing a novel alcohol-based vehicle ignition-interlock device. Accumulating evidence shows that one of the ethyl alcohol absorption peaks in the near-infrared region is present at 1,185 nm. We combined this with our recent development of a non-invasive optical method for blood glucose measurement, which we call pulse glucometry, using blood volume pulsations in a finger within a cardiac cycle. Thus, we developed a novel method, pulse alcometry, for non-invasive measurement of BAC. We calculated second derivative values of optical density (ODλ”) to remove baseline over a band including three wavelengths, 1,150 nm, 1,185 nm, and 1,220 nm. Then, a simple linear regression analysis was performed with the measured ODλ” to predict BAC levels. In 3 healthy male volunteers, during alcohol intake and washout, periodic optical measurements using the present device were made simultaneously with collection of blood samples for in vitro BAC analysis. In leave-one-out cross validations within an individual, the measured BAC and the predicted BAC correlated well (r = 0.773∼0.846, mean absolute error = 0.134∼0.333mg/ml). We conclude that, from the results of this preliminary study, the new method appears to be able to estimate BAC levels non-invasively. However, further investigations in a larger group of subjects will be needed in order to determine fully the operational performance of this new measurement system.