This paper proposes a method for selecting photoplethysmogram features for estimating systolic blood pressure (SBP), which uses the signal-to-noise ratio (SNR) obtained from the Taguchi method. ...Cuffless estimation of blood pressure using just one photoplethysmograph was carried out based on the photoplethysmogram features. However, these features are highly vulnerable to noise generated by sources such as individual variability, resulting from factors such as age and gender. Therefore, features need to be robust against such noise for accurate estimation of blood pressure. In this study, we used an orthogonal array and the SNR from the Taguchi method for selecting features of multiple regression analysis that are robust against noise. We estimated SBP from two datasets by applying the proposed feature selection method to multiple regression analysis. The obtained results show that the correlation coefficients between the actual measurement values and the estimated values were 0.88 and 0.87 for datasets 1 and 2, which are higher than those of similar methods used for comparison purposes. This confirms the effectiveness of the proposed method in estimating SBP.
This paper proposes a cuff-less systolic blood pressure (SBP) estimation method using partial least-squares (PLS) regression. Level-crossing features (LCFs) were used in this method, which were ...extracted from the contour lines arbitrarily drawn on the second-derivative photoplethysmography waveform. Unlike conventional height ratio features (HRFs), which are extracted on the basis of the peaks in the waveform, LCFs can be reliably extracted even if there are missing peaks in the waveform. However, the features extracted from adjacent contour lines show similar trends; thus, there is a strong correlation between the features, which leads to multicollinearity when conventional multiple regression analysis (MRA) is used. Hence, we developed a multivariate estimation method based on PLS regression to address this issue and estimate the SBP on the basis of the LCFs. Two-hundred-and-sixty-five subjects (95 males and 170 females (Mean ± Standard Deviation) SBP: 133.1 ± 18.4 mmHg; age: 62.8 ± 16.8 years participated in the experiments. Of the total number of subjects, 180 were considered as learning data, while 85 were considered as testing data. The values of the correlation coefficient between the measured and estimated values were found to be 0.78 for the proposed method (LCFs + PLS), 0.58 for comparison method 1 (HRFs + MRA), and 0.62 for comparison method 2 (HRFs + MRA). The proposed method was therefore found to demonstrate the highest accuracy among the three methods being compared.
The locomotive syndrome risk test was developed to quantify the decrease in mobility among adults, which could eventually lead to disability. The purpose of this study was to establish reference ...values for the locomotive syndrome risk test for adults and investigate the influence of age and sex.
We analyzed 8681 independent community dwellers (3607 men, 5074 women). Data pertaining to locomotive syndrome risk test (the two-step test, the stand-up test, and the 25-question geriatric locomotive function scale GLFS-25) scores were collected from seven administrative areas of Japan.
The reference values of the three test scores were generated and all three test scores gradually decreased among young-to-middle-aged individuals and rapidly decreased in individuals aged over 60 years. The stand-up test score began decreasing significantly from the age of 30 years. The trajectories of decrease in the two-step test score with age was slightly different between men and women especially among the middle-aged individuals. The two physical test scores were more sensitive to aging than the self-reported test score.
The reference values generated in this study could be employed to determine whether an individual has mobility comparable to independent community dwellers of the same age and sex.
This paper proposes a method to estimate the vascular age from the reflected photoplethysmogram (PPG) waveform. Mobile devices such as smartphones are rapidly penetrating daily life, and health ...management using them is expected. This paper deals with a method of estimating the vascular age using a reflective PPG sensor attached to a mobile device. In the proposed method, contour lines are drawn on the PPG and the derivative PPG waveform, and features are extracted from them. Since many features are extracted, the influences of multicollinearity are concerned. Therefore, partial least squares regression which is not affected by multicollinearity was used as an estimation method. We compared the estimation accuracy with the conventional method using height ratio feature.
Zoledronic acid (ZOL), a third-generation bisphosphonate, inhibits bone resorption, as well as exhibiting direct antitumor activity. To date, however, the combined effects of ZOL and ionizing ...radiation (IR) have not been assessed in patients with soft tissue sarcoma. We have, therefore, assessed the combined effects of ZOL and IR in fibrosarcoma cells. HT1080 fibrosarcoma cells were treated with ZOL and/or IR, together or sequentially and the antitumor effects were assessed. We found that ZOL significantly enhanced IR-induced apoptosis, especially when cells were treated with ZOL followed by IR. We, therefore, assessed the detailed mechanism of sequential treatment with ZOL and IR. Cells in G2 and M phases, the most radiosensitive phases of the cell cycle, were not increased by low concentrations of ZOL. However, the levels of expression of Akt, ERK1/2 and NF-κB proteins, all of which are related to radioadaptive resistance, were increased within a short time after irradiation with 3 Gy, and this expression was inhibited by a low concentration of ZOL, which blocked the prenylation of small GTPases. This sequential treatment also increased the generation of reactive oxygen species (ROS). These results suggest that the combination of ZOL with IR may be beneficial in treating patients with soft tissue sarcoma.
This paper proposes a contour-line-based feature and analyzes its relationship with blood pressures. The proposed method extracts an existence and a variation property from the contour lines drawn on ...the waveform. The existence property is the total length of the contour line in the waveform. The variation property is the number of intersection points of the waveform and contour lines. The proposed feature is a quite different from the conventional feature, which is extracted from peak wave height. We made a comparative experiment whose participants are 71 females with ages ranging between 18 and 94 years. The result showed that the proposed feature was obtained highly correlation with the blood pressure than the conventional peak feature.
Blood pressure estimation by using pulse wave sensor Suzuki, Arata; Tsuji, Yoshiki; Ue, Mizuki ...
Transactions of Japanese Society for Medical and Biological Engineering,
2014, Volume:
52, Issue:
Supplement
Journal Article
Peer reviewed
Open access
This paper describes a method for estimating blood pressure by using just one pulse wave sensor. Generally, to be able to measure blood pressure, cuffs are required for applying pressure, blood ...pressure measurement is time and effort consuming, and continuous measurements cannot be performed. If we are able to measure blood pressure without the use of cuff, we can solve these problems. However, features that obtained by pulse wave sensor are highly vulnerable to noise generated by various factors. In this paper, we evaluated the features using Taguchi's signal-to-noise ratio, and we extracted the features that are robust against noises. The effectiveness of the proposed method confirmed through the experiment of blood pressure estimation.
This paper proposes a method to estimate the vascular age from the reflected photoplethysmogram (PPG) waveform. Mobile devices such as smartphones are rapidly penetrating daily life, and health ...management using them is expected. This paper deals with a method of estimating the vascular age using a reflective PPG sensor attached to a mobile device. In the proposed method, contour lines are drawn on the PPG and the derivative PPG waveform, and features are extracted from them. Since many features are extracted, the influences of multicollinearity are concerned. Therefore, partial least squares regression which is not affected by multicollinearity was used as an estimation method. We compared the estimation accuracy with the conventional method using height ratio feature.
Introduction
There are approximately 13 million patients with osteoporosis in Japan; however, only 20% of them receive treatment. This study compared the 4‐year continuation rates of osteoporosis ...drugs at different dosing intervals across throughout Japan.
Materials and methods
Receipt data were analyzed to determine the continuation of osteoporosis medication in patients who began treatment at 210 hospitals throughout Japan between October 2016 and September 2017. Continuation rates were compared using Kaplan–Meier curves and log‐rank tests.
Results
The 4‐year continuation rates of daily, weekly, monthly, semi‐annual, and yearly medications nationwide were 8.6%, 16.5%, 13.5%, 31.0%, and 26.0%, respectively. The 4‐year continuation rates for semi‐annual and yearly drugs were significantly higher than daily, weekly, monthly drugs.
Conclusion
Throughout Japan, the 4‐year treatment continuation rates of daily, weekly, monthly, semi‐annual, and yearly osteoporosis drugs all decreased over time. However, the continuation rates of semi‐annual and yearly drugs in the fourth year were significantly higher than those for the other dosing regimens. Therefore, injectable drugs with dosing intervals ≥6 months may improve continuation rates of osteoporosis drugs. Geriatr Gerontol Int 2023; 23: 665–670.
In various regions of Japan, the 4‐year treatment continuation rates of daily, weekly, monthly, semi‐annual, and yearly drugs of osteoporosis drugs with different dosing intervals decreased over time. However, the continuation rates of semi‐annual and yearly drugs in the fourth year were significantly higher than those of the other drugs.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
This paper proposes a contour-line-based feature and analyzes its relationship with blood pressures. The proposed method extracts an existence and a variation property from the contour lines drawn on ...the waveform. The existence property is the total length of the contour line in the waveform. The variation property is the number of intersection points of the waveform and contour lines. The proposed feature is a quite different from the conventional feature, which is extracted from peak wave height. We made a comparative experiment whose participants are 71 females with ages ranging between 18 and 94 years. The result showed that the proposed feature was obtained highly correlation with the blood pressure than the conventional peak feature.
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