近藤 輝

BACKGROUND: Although smart insoles have emerged as promising tools for long-term gait analysis, these devices face a trade-off between wearability (where sensor modules are fully accommodated within a compact insole) and data quality (where sensor modules cannot be accommodated within the insole). Integrating an inertial measurement unit (IMU) with pressure sensors and fully embedding all modules may resolve this trade-off; however, the reliability and validity of such a smart insole remain unverified. RESEARCH QUESTION: Can a smart insole with an IMU and pressure sensors provide reliable and valid spatiotemporal gait parameters comparable to an instrumented walkway? METHODS: Twenty-six healthy volunteers (mean age 26.0 ± 5.6 years) performed walking tasks while wearing the smart insole. Reliability was assessed by comparing spatiotemporal parameters between two sessions of walking trials. Validity was evaluated against a gold-standard instrumented walkway positioned along the path. Data were analyzed using intraclass correlation coefficients (ICCs) and Bland-Altman analysis. RESULTS: ICC values indicated good to excellent reliability (0.93-0.95) and validity against the instrumented walkway (0.70-0.99). Although Bland-Altman analysis revealed systematic differences, these deviations were acceptable (<4% of mean difference), with 95% limits of agreement ratios under 8% for all parameters. SIGNIFICANCE: The smart insole incorporating IMU and pressure sensors, characterized by a highly wearable and cable-free design, provides reliable and valid spatiotemporal gait parameters. Future studies involving broader populations and real-world settings are warranted to further validate its applicability.

BACKGROUND: Gait-a frequently performed activity of daily living-is thought to reflect multiple dimensions of an individual's physical and cognitive status. Individuals with frailty or mild cognitive impairment (MCI) show decreased gait speed. However, previous studies have not simultaneously considered both statuses, although they frequently co-occur and may act as confounders. The direct association between frailty and gait is well-understood. In contrast, the association between cognitive decline-independent of physical function-and decreased gait speed, as well as the relationship among these three factors (frailty, cognitive decline, and gait speed), is not fully understood. METHODS: This study examined the effect of MCI on gait speed after accounting for frailty. Older individuals were categorized as (1) frailty with MCI, (2) frailty without MCI, (3) pre-frailty with MCI, (4) pre-frailty without MCI, (5) non-frailty with MCI, and (6) non-frailty without MCI. Frailty was assessed using the Kihon checklist and MCI using the Montreal Cognitive Assessment. Participants completed a 10-m walk test under two conditions: comfortable walking and fast walking. Two types of analyses were conducted: mediation analysis and two-way analysis of covariance (ANCOVA). RESULTS: Mediation analysis supported independent relationships between frailty and MCI status and gait speed, suggesting a direct association between MCI and gait speed, even when accounting for frailty. In addition, two-way analysis of covariance indicated significant main effects of both frailty and MCI on gait speed, with no significant interaction between them under the two walking conditions. CONCLUSIONS: These findings suggest that the observed association between MCI and gait speed is largely independent from frailty status, providing additional evidence supporting the association between cognitive function and gait performance.

Mobile phones are increasingly being proposed as tools to support daily life among older adults with cognitive impairment; however, empirical data on their actual ownership and use in clinical settings remain limited. This study aimed to clarify mobile phone ownership and usage patterns among older adults with cognitive impairment attending memory clinics. Eighty-two older adults with cognitive impairment (mean age: 80.4 y; mean Mini-Mental State Examination score: 18.1 points) were included. Data were collected using caregiver-administered questionnaires and analyzed descriptively. Among the participants, 65 (79.3%) owned a mobile phone, with an almost equal distribution of smartphones (n=33) and featured phones (n=32). Fifteen phone owners did not use their devices. Reported use was largely limited to basic communication functions. These findings indicate limited mobile phone ownership and functional use among older adults with cognitive impairment and underscore the need to consider cognitive limitations when implementing mobile technologies.

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.