Kento Katagiri

PURPOSE: Adjusting the tilt and recline angles of a wheelchair is recommended as one of the approaches for preventing pressure injuries associated with mechanical loading in wheelchair users. However, maintaining a fixed inclination may increase pressure on other body areas, raising concerns about the time-dependent risk of ulcers. To address this issue, we proposed an electrically powered wheelchair equipped with a mechanism that continuously changes the tilt angle, similar to the motion of a rocking chair, and developed a prototype as a proof of concept. This cross‑sectional study aimed to evaluate the effectiveness of the prototype wheelchair in reducing and redistributing interface pressure. MATERIALS AND METHODS: Eight healthy participants were enrolled in this study. The electrically controlled tilt angle was programmed to cycle from 0° to 30° in 50 s. Reclining angles were set at 0°, 10°, 20°, and 30°. The pressure at the head, back, and buttocks was recorded. RESULTS: The peak pressure in these areas changed dynamically with tilt variation; increasing the tilt angle raised the peak pressure at the head and back while reducing it at the buttocks. Increasing the reclining angle amplified these changes in the head and buttocks but had no effect on the back. CONCLUSION: Our findings suggest that continuous tilt variation may reduce prolonged exposure to excessive pressure, potentially reducing the risk of ulcers in the buttocks associated with mechanical loading in wheelchair users.

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.

PURPOSE: In real-world care settings, wheelchair operation from multiple directions would be optimal. This study aimed to determine how caregivers operate the omni-directional accessible (OA) wheelchair, which features four swivel casters to achieve omni-directional movement and two vertical handles for caregivers located at the front of the armrest and its effectiveness for reducing time of wheelchair operations. METHOD: Twenty healthy volunteers were randomly assigned to either the OA (n = 10) or conventional (n = 10) wheelchair group. Participants performed a wheelchair operation task in a simulated care setting. We measured the caregiver's position during wheelchair operation and the task completion time required for the wheelchair operation task. RESULT: The results showed that all participants in OA group operated the wheelchair from positions other than the rear. This tendency became more pronounced as the trial number increased, contributing to shorter task completion time than conventional wheelchair. CONCLUSION: These findings suggest that OA wheelchairs are suitable and effective for use in real-world care settings.

Constipation is a prevalent condition that negatively impacts health and quality of life. Inadequate physical activity is a known contributing factor, often associated with reduced gut motility. However, the physiological mechanism linking physical activity and constipation remains unclear. Particularly research on the immediate effects of physical activity on peristalsis is scarce. Therefore, we aimed to elucidate this mechanism by examining the immediate effects of physical activity on gut motility in healthy adults. Twenty-one participants were instructed to walk on a treadmill for 20 min. Bowel sounds were assessed at rest and at intervals up to 15 min after walking. Bowel sounds were used as indirect markers of gut motility. We calculated the sum of the absolute signal amplitudes of bowel sounds, the percentage of bowel sounds duration, and number of discrete bowel sounds, which have been proposed as indices of gut motility. All the indices increased significantly 1-2 min post-exercise compared to resting values. This increase may be attributed to changes in the autonomic nervous system and local reflexes caused by biomechanical oscillations. In addition, gut motility activation might explain the effects of physical activity intervention on constipation and offer insights into its potential role in managing the condition.