Kotaro TAKEDA

Background Pulmonary rehabilitation (PR) for patients with chronic obstructive pulmonary disease (COPD) improves exercise tolerance and COPD assessment test score (CAT). Oxygen supplementation during PR facilitates exercise physiological benefits. This study aimed to assess the feasibility of a trial comparing two oxygen supplementation methods, with the hypothesis that both would be effective and produce distinct outcomes. Methods This double-blind, crossover, randomized controlled trial compared two PR programs—Program A (including PR under FiO₂ 0.3) and Program B (including PR under FiO₂ 0.5)—using high-flow nasal cannula oxygen therapy in patients with COPD and exertional dyspnea (n = 6). Data on the 6-minute walk distance (6MWD), CAT, muscle strength, body composition analysis, respiratory function, and joint range of motion were collected. Participants underwent one month of regular PR followed by two months of oxygen-supplemented PR, with data collected again after this period. Statistical significance was set at 0.05 with a power of 0.8, and the required sample size was calculated accordingly. Results The required sample size could not be calculated based on the 6MWD. The improvement in CAT by Program A was greater than that by Program B. The improvements in muscle parameters by Program B were greater than those by Program A. The standardized effect size and the corresponding required sample sizes for the CAT, quadriceps muscle power, lower leg circumference, trunk muscle mass, and leg muscle mass were 0.32/81, 0.66/8, 0.17/114, 0.27/88, and 0.24/56, respectively. Conclusions Given the small number of participants, the 6MWD and CAT were not appropriate primary endpoints for comparing the effectiveness of the two oxygen supplementations during PR in patients with COPD. However, the quadriceps muscle power was identified as the most suitable primary endpoint among all the investigated parameters.

Abstract The hand laterality judgment task requires participants to determine whether a picture of a hand, presented at various rotational angles, depicts a left or right hand. Several strategies have been suggested to be involved in task performance: in particular, palm-view pictures are thought to rely on motor imagery (MI), whereas back-view pictures are thought to rely on ‘nonMI’ (i.e., without motor imagery) strategies, including visual imagery (VI). However, the influence of repeated task execution on performance strategies remains unclear. This study examined the relationship between self-reported strategies and response time (RT) profiles during a 512-trial hand laterality judgment task in 42 healthy adults. Based on post-task self-reports for palm-view pictures, participants were classified into the MI group, consistently using MI throughout the trials, and the MI–nonMI group, switching from MI to nonMI during the repeated trials. In the MI group, RT profiles consistently showed longer RTs for lateral palm-view pictures (outward-pointing fingers) than for medial orientations (inward-pointing fingers), characteristic of MI use, across both halves of the task. The MI–nonMI group showed similar RT patterns initially, but in the second half, RT differences between lateral and medial orientations diminished, suggesting a shift toward VI-like characteristics. These findings suggest that although both groups may have used MI, RT trends varied according to the participants’ self-reported strategies. In the MI group, both explicit self-report and implicit RT profiles indicated sustained MI use, whereas the MI–nonMI group, self-reports indicated a strategy shift to nonMI, and their RT profiles suggest a combined use of MI and nonMI.