This study was conducted as a single-center, prospective feasibility study at a Japanese convalescent rehabilitation hospital between April 2022 and March 2024. Participants were recruited using convenience sampling. Research staff periodically screened electronic medical records of newly admitted patients and invited those who met the eligibility criteria during the recruitment period. Because this was a feasibility study, no formal sample size calculation was performed. We aimed to recruit approximately 20 participants based on published methodological recommendations for pilot and feasibility studies, while also considering the feasibility of recruitment and intervention delivery within our clinical setting [14]. The inclusion criteria were as follows: (1) age ≥65 years, (2) a diagnosis of stroke, and (3) independent in self-care except bathing. The exclusion criteria were severe communication impairment due to aphasia or disturbance of consciousness, severe visual or hearing impairment, serious comorbidities (eg, heart disease or cancer), severe psychiatric disorders (eg, depression or schizophrenia), and planned discharge within 14 days. The criterion requiring independence in self-care except bathing was used to focus on patients whose functional status was compatible with anticipated home discharge and potential postdischarge DHT use, thereby allowing evaluation of the feasibility of the instructional program in the intended target population.

This study was conducted in accordance with the Declaration of Helsinki and was approved by the Ethics Committee of Tokyo Bay Rehabilitation Hospital (approval number 275). All participants provided written informed consent before study participation. Study data were deidentified before analysis and stored securely with access restricted to authorized study personnel. No personally identifiable information is reported in this manuscript. Participants did not receive financial compensation for participation.

Each task was assessed using a 5-point ordinal scale based on daily therapist observation or device logs. The scoring system was 5 (independent without assistance), 4 (independent with reference to a manual), 3 (possible with verbal cueing), 2 (possible after modeling), and 1 (unable to perform). For this feasibility study, independence was defined as the ability to complete a task without direct human assistance. Therefore, scores of 4 and 5 were classified as indicating independence because participants were able to complete the task without direct human assistance, with the manual serving as an external reference tool that could also be used after discharge. In addition to task performance, participants’ perceived usability of the integrated digital device environment was assessed after the 14-day intervention using the System Usability Scale (SUS).

The SUS is a widely used tool for evaluating the perceived usability of a system or product [15], consisting of 10 statements that are scored on a 5-point Likert scale (from 1 “strongly disagree” to 5 “strongly agree”). To calculate the total SUS score, the score contribution of each item is first converted to a 0 to 4 scale: for positively worded items (1, 3, 5, 7, and 9), the contribution is the selected scale point minus 1; for negatively worded items (2, 4, 6, 8, and 10), it is 5 minus the selected scale point. The sum of these converted values is then multiplied by 2.5, yielding a composite usability score ranging from 0 to 100. A higher SUS score is associated with greater usability. SUS scores were interpreted with reference to previously reported adjective ratings [16]. The SUS was used to assess participants’ perceived usability of the integrated digital device environment used throughout the study. The integrated digital device environment comprised the preconfigured tablet, chat app, video calling system, and wearable device, which participants evaluated as a single integrated environment rather than as individual devices or apps. Individual SUS items were not interpreted separately, as the SUS is designed to be evaluated as a composite score.

Medical records were reviewed to collect general characteristics, including age, sex, type of stroke, side of paralysis, duration from stroke onset to admission, and length of hospital stay. Clinical assessments included the Mini-Mental State Examination (MMSE), Fugl-Meyer Assessment-Upper Extremity (FMA-UE), and Functional Independence Measure (FIM).

The MMSE is a questionnaire for evaluating cognitive function [17]. It consists of 11 items as follows (maximum score for each item): orientation to time (score: 5), orientation to place (score: 5), registration of 3 words (score: 3), attention and calculation (serial sevens or spelling; score: 5), recall (score: 3), naming (score: 2), repetition (score: 1), verbal comprehension (score: 3), written comprehension (score: 1), writing (score: 1), and construction (score: 1). The maximum score is 30 points, with a higher score representing greater cognitive function.

The FMA-UE score was used to measure upper extremity impairment [18]. The FMA-UE includes 30 motor function items and 3 reflex function items, scored on a 3-point ordinal scale (0=cannot perform, 1=partially performs, and 2=completely performs), with higher scores indicating better motor function (total score: 0‐66 points). The FMA-UE total score classified the severity of upper extremity paralysis, with scores ≤19 classified as severe, 20 to 47 as moderate, and ≥48 as mild [19].

The FIM is an observational evaluation tool for functional disability [20]. The FIM consists of 13 motor items and 5 cognitive items. The motor items consist of the following 4 categories: self-care (eating, grooming, bathing, upper body dressing, lower body dressing, and toileting), sphincter control (bladder management and bowel management), transfers (bed, chair, and wheelchair; toilet; and tub and shower), and locomotion (walking and wheelchair use and stairs). The cognitive items consist of 2 categories: communication (comprehension and expression) and social cognition (social interaction, problem-solving, and memory). Each item is scored on a 7-point scale ranging from 1 (total assistance or not testable) to 7 (complete independence) points. The total score ranges are 18 to 126 points, 13 to 91 points, and 5 to 35 points for the total score, motor score, and cognitive score, respectively, with a higher score representing greater functional independence.

Characteristics were summarized according to variable type and distribution. Categorical variables were summarized using frequencies and percentages. Task performance scores were summarized using frequencies and percentages for each score category. Clinical assessment scores were summarized using means (SDs) or medians (IQRs), as appropriate, after checking their distributions using Q-Q plots. SUS scores were summarized using the mean and SD. The number and percentage of participants achieving independence in each task and across all 7 tasks were summarized for days 1 and 14. Participants who achieved independence in all 7 tasks on day 14 were considered to have achieved mastery of digital device use.

This study investigated the feasibility and usability of a structured digital device instruction program for older adults with stroke in a convalescent rehabilitation ward. Following a 14-day protocol, most participants achieved independence across all predefined digital tasks, and the integrated digital device environment demonstrated moderate perceived usability. These findings suggest that a structured, stepwise instructional approach can be implemented in this population and highlight the importance of usability when implementing DHTs.

Most participants in this study successfully acquired digital device operation, which may be attributed to the structured learning opportunities and support system provided. In the context of poststroke rehabilitation, the implementation of DHT requires attention not only to individual characteristics such as physical and cognitive limitations but also to contextual factors, including instructional opportunities and support infrastructure [10]. Previous studies have reported that the presence or absence of support is a critical factor in DHT implementation [9], particularly emphasizing the facilitating role of active involvement by health care professionals [11]. Additionally, previous studies have shown that for older adults, providing tutorials and stepwise instructions at the initial stage of mHealth introduction is necessary to reduce learning barriers [21]. Similarly, structured digital skills training has been shown to improve digital device proficiency among older adults [22]. In this study, the instructional protocol was deliberately designed to incorporate these facilitating factors, which may have contributed to digital skill acquisition. These findings suggest that simplifying user interfaces alone is not sufficient; rather, successful adoption may require an integrated design that addresses the full learning process through both structured instruction and ongoing support. This point may be particularly important in convalescent rehabilitation, where patients have a limited yet structured opportunity to acquire digital skills before discharge. Beyond its role as an educational approach, this structured instructional protocol may inform future implementation strategies for integrating DHTs into routine convalescent rehabilitation practice. Nevertheless, video calling had the lowest mastery rate among all tasks, which is likely attributable to the procedural complexity involved. A previous study has identified complexity as a major barrier to technology use among older adults [23]. In our protocol, video calling involved multiple distinct steps—including launching a specific app, enabling microphone and camera functions, and adjusting settings—which may have posed additional challenges. Therefore, in addition to structured support, further simplification strategies, such as consolidating platforms and limiting the number of technologies used, may also be essential.

In addition to demonstrating the feasibility of the instructional protocol, the integrated digital device environment showed moderate perceived usability, as assessed by the SUS. A previous study has underscored the importance of usability—defined by ease of use and intuitive interface design—in the implementation of DHT in rehabilitation settings [10]. In older populations, incorporating age-inclusive design principles has been shown to improve digital accessibility, satisfaction, and autonomy [24]. Moreover, mobile app guidelines emphasize the importance of simplifying interactions and enlarging visual elements to accommodate age-related physical and cognitive changes [25]. In this study, usability was enhanced through preconfiguration of large text displays and the development of a minimal, image-based manual tailored to older users. These findings highlight that effective DHT implementation requires not only technical deployment but also attention to users’ subjective experience and perceived ease of use. Taken together, these findings suggest that attention to usability should be an important consideration when implementing DHT for older adults with stroke, particularly in poststroke rehabilitation settings where age-related and neurological factors may influence technology adoption.

This study provides one of the few detailed reports of a clinically applicable protocol for implementing DHT among older adults with stroke admitted to a convalescent rehabilitation ward. Previous research has often lacked systematic use of implementation frameworks, highlighting the need for more structured implementation studies in rehabilitation contexts [10]. In contrast, our study describes a structured implementation approach, including a stepwise instructional protocol, device specifications, age-inclusive preparatory measures, and usability considerations, which may provide a practical framework for future implementation studies. The feasibility of this approach was likely enhanced by the unique characteristics of the convalescent rehabilitation ward system in Japan. The relatively long inpatient stays and structured daily schedules in this setting allowed for gradual exposure to DHT and integration of support into routine rehabilitation activities. Furthermore, as convalescent rehabilitation wards are designed to support discharge planning, skill acquisition during hospitalization may facilitate postdischarge self-management and community-based DHT use. Implementation models such as the one described in this study may provide a practical framework for future implementation efforts aimed at supporting DHT use after discharge. Future studies are needed to evaluate their effects on long-term DHT adoption and integrated community care. However, in this study, the instructional sessions were conducted outside of regular clinical hours by research staff. In addition, device preparation and preconfiguration were performed specifically for the study and may require further simplification for routine clinical implementation. Thus, practical challenges remain regarding who should deliver such support, when it should be provided, and how it can be operationalized in routine clinical workflows. Therefore, future implementation efforts must focus on developing and evaluating sustainable implementation models that can be integrated into existing clinical operations. These may include role-sharing among interdisciplinary staff, streamlined device preparation and configuration procedures, and practical tools to support DHT instruction in resource-constrained environments.

This study has several limitations. First, this was a single-center, single-arm feasibility study with a short duration, no comparator group, and a small sample size (n=19), which limits the ability to attribute the observed findings to the instructional program and restricts the generalizability of the results. Second, participants were required to be independent in self-care except bathing, resulting in a study population with relatively high functional independence. Accordingly, the findings may not be generalizable to stroke survivors with more severe physical or cognitive impairments. However, this eligibility criterion was intentionally adopted to evaluate the feasibility of digital device instruction in patients considered potential users of DHTs after discharge, thereby reflecting the intended target population for implementation in convalescent rehabilitation. Third, because the study assessed only short-term acquisition of digital skills and did not include a follow-up assessment, the long-term retention of these skills, actual use after discharge, and potential effects on health-related outcomes remain unclear and warrant further investigation. In addition, independence was operationally defined as task completion without direct human assistance, including completion with reference to the manual. This definition may overestimate unaided real-world autonomy because some participants still relied on the manual to complete certain tasks. Therefore, the reported independence should be interpreted as the ability to perform tasks without direct human assistance rather than complete mastery without external support. Fourth, the SUS is a subjective measure and may be influenced by cognitive function in older adults. Future research should incorporate additional objective usability measures, such as task completion time, error rates, and device use logs, to complement subjective assessments. In addition, because the SUS was originally developed to evaluate a single system, its application to the integrated digital device environment should be interpreted cautiously. Accordingly, the SUS score reflects participants’ overall perception of the integrated digital device environment rather than the usability of any individual device or app. Finally, the devices and instructional methods used in this study were specific to the intervention and context; therefore, future studies should explore the applicability of the approach using different technologies, software, or remote support models. Despite these limitations, this study presents one of the few systematically described protocols for supporting DHT adoption in convalescent rehabilitation settings, offering valuable insights from an implementation science perspective. Moving forward, the development and evaluation of long-term operational models will be essential to determine how skills acquired during inpatient rehabilitation can be maintained and applied in home environments, contributing to self-management and remote care in older adults with stroke.

This study demonstrated the feasibility of implementing a structured digital device instruction program for older adults with stroke in a convalescent rehabilitation ward. Most participants achieved independence across the predefined digital tasks during the 14-day program, and the integrated digital device environment demonstrated moderate perceived usability. These findings suggest that structured instruction delivered during inpatient rehabilitation may facilitate the acquisition of basic digital competencies before discharge. However, because this was a single-center feasibility study with a small sample and no comparator group, the findings should be interpreted cautiously. Future controlled studies should evaluate the long-term retention of digital skills, postdischarge DHT use, clinical outcomes, and the scalability of this implementation approach across different rehabilitation settings.