OTAKA YOHEI

We aimed to evaluate the applicability of a newly developed joint angle measurement system comprising six-axis inertial measurement unit sensors and tablet-based application for estimating joint angles from angular velocity and acceleration data. The application calculated orientation angles from single sensor data, with relative angles calculated using multiple sensors. In experiment 1, validity and reliability were examined using a test device. In experiment 2, static angles of five joints were calculated in four healthy participants using attached sensors and compared with universal goniometer values. In experiment 3, usability and satisfaction were evaluated using the System Usability Scale (SUS) and Quebec User Evaluation of Satisfaction with Assistive Technology (QUEST)-like scale. In experiment 1, mean difference and root mean squared error (RMSE) between the developed system and test device were < 0.2° and < 1.0°, respectively, across all axes. In experiment 2, when data from all joints were pooled, mean difference and RMSE were 0.2° and 3.8°, respectively. Mean difference and RMSE across each joint were < 5°, indicating the system is comparable to universal goniometer. In experiment 3, median SUS and QUEST-like scores were 73.8 and 4.0, respectively, indicating good usability and satisfaction. The developed system has high accuracy and sufficient validity for human joint angles, with good usability and satisfaction.

OBJECTIVES: A new classification of heart failure based on the effects of medication has recently come into use. According to this classification, heart failure is divided into heart failure with normal ejection fraction (HFnEF; defined as an EF ≥55% for men and ≥60% for women) and non-HFnEF. However, the characteristics of patients with HFnEF are still unclear. Accordingly, in this study, we sought to identify the background characteristics, including non-cardiac factors, of patients with HFnEF. METHODS: We retrospectively divided 304 eligible patients who were hospitalized for worsening heart failure at our institution between December 2020 and December 2022 into an HFnEF group (n=37) and a non-HFnEF group (n=267) and compared their demographic and clinical characteristics. RESULTS: There were more elderly patients in the non-HFnEF group, along with fewer patients with coronary artery disease and low serum hemoglobin and NT-proBNP levels and a higher proportion of patients with a low skeletal muscle index (<7.0 kg/m2 for men and <5.7 kg/m2 for women). Multivariate analysis with addition of patient sex identified a low skeletal muscle index (odds ratio 2.96, p<0.01) to be an independent determinant of HFnEF along with older age and low NT-proBNP. CONCLUSIONS: A low skeletal muscle index was significantly more common in patients with HFnEF than in those with non-HFnEF. Intensive nutrition and exercise therapy to increase skeletal muscle mass may improve the prognosis in patients with HFnEF who respond poorly to standard pharmacological treatment.

BACKGROUND: Various digital biomarkers have been explored to detect cognitive impairment in community-dwelling older individuals, among which electricity consumption (EC) data obtained from smart meters are novel and promising because they pose no burden to the individuals. OBJECTIVE: The study aimed to explore the potential of EC as a digital biomarker to screen older individuals with cognitive impairment living alone. METHODS: We recruited 40 older individuals living alone and recorded their 1-year daily household EC data. We used the Japanese version of the Montreal Cognitive Assessment to categorize participants into 2 groups: those with and without cognitive impairment. As the pattern of daily household EC is different between lower and higher temperature ranges because of the use of heating and cooling equipment, we divided the daily household EC into 3 temperature ranges. Using a linear mixed model, we evaluated the association between daily household EC, daily outside temperature, and the groups. RESULTS: After excluding 12 participants, they were categorized into 2 groups: those with (10/28, 36%) and without cognitive impairment (18/28, 64%). The daily household EC data consisting of 9391 points showed two characteristics: (1) daily household EC was significantly lower in the group with cognitive impairment than in the group without cognitive impairment in the high temperature range (2.158 kWh at 25 °C, P=.02; 3.712 kWh at 30 °C, P<.001). The increase in EC with rising temperature from 25 °C to 30 °C was less in the group with cognitive impairment (2.387 kWh, P<.001) than in the group without cognitive impairment (3.940 kWh, P<.001); and (2) a tendency for lower daily household EC in the group with cognitive impairment was observed in the moderate temperature range (1.795 kWh at 15 °C, P=.06; 1.582 kWh at 20 °C, P=.08). CONCLUSIONS: The group with cognitive impairment may use less cooling equipment in the high temperature range and fewer home appliances in the moderate temperature range. Daily household EC might be useful in screening cognitive impairment in older individuals living alone.