森 直樹

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.

Radial extracorporeal shock wave therapy showed immediate spasticity reduction and sustained range of motion improvement in a patient with subacute stroke. However, twice-weekly sessions were insufficient for lasting spasticity control, suggesting that more frequent treatments may be required. Further research is needed to optimize treatment protocols.

To address longstanding challenges in evaluating hip protectors and compliant flooring for preventing hip fractures in the elderly, test systems should replicate hip loading and accurately assess their performance. This study evaluated a thigh impact test system (drop tower) against human body model (HBM) simulations of a sideways fall. A pelvis spring-damper model representing pelvic compliance was incorporated into the system. The test system with the pelvic model reproduced HBM-derived femoral neck forces, whereas systems without it overestimated them. These results highlight the importance of incorporating a pelvic model to improve the biofidelity of thigh impact test systems.