User-Centered Design and Evaluation of a "Lehuo Pingpang" Exergame for Older Adults With Mild Cognitive Impairment: Cross-Sectional Convergent Mixed Methods Study.

Background: Physical activity is one of the preferred interventions for mild cognitive impairment (MCI); however, the physical activity levels and adherence of older adults with MCI are particularly limited. Exergames are expected to be a key strategy to address these issues. However, existing exergames lack usability among the older adult population. Objective: We aimed to design and develop an MCI-centered exergame for older adults and test its usability. Methods: We used a cross-sectional, convergent mixed methods study with a single-group observational design, comprising a user-centered design phase (part 1) and a usability evaluation phase (part 2). In part 1, the "Lehuo Pingpang" virtual reality (VR) table tennis exergame prototype was designed and developed using Unity3D (Unity Technologies) and a PICO 4 Pro system. In part 2, a total of 12 older adults (aged ≥60 years) with MCI were recruited via convenience sampling from community, home-based, and institutional care settings in Changsha, Hunan. Usability was evaluated using a convergent mixed methods approach. Immediately after a supervised, independent gaming session, quantitative usability was measured using the System Usability Scale, while qualitative feedback regarding user experiences and barriers was gathered concurrently through face-to-face semistructured interviews. Data integration occurred at the interpretive level to synthesize the quantitative metrics with qualitative themes. Results: In part 1, an original design framework for MCI exergames was constructed. Group discussions selected table tennis as the core activity and PICO 4 Pro as the hardware platform based on clarity and physical comfort. A multidisciplinary expert meeting (n=8) optimized the preliminary plan across six dimensions, resulting in the final prototype Lehuo Pingpang. In part 2, 12 participants (mean age 69.08, SD 6.08 y) evaluated the prototype. The mean System Usability Scale score was 79.38 (SD 12.89; 95% CI 71.19-87.57), indicating acceptable and reliable usability. Qualitative interviews (data saturation achieved at the 9th interview, with 12 completed) identified 2 main themes and 7 subthemes categorized into positive experiences and deficiencies. Mixed methods integration demonstrated that quantitative usability and learnability indicators strongly converged with qualitative praise for simple operation and safety functions, though complemented by learning friction from controller button complexity and VR unfamiliarity, as well as minor user interface flaws (small buttons). Crucially, while quantitative confidence was high, long-term frequent-use intentions were moderate. Qualitative findings revealed that this was driven by physical discomfort (eg, VR dizziness and facial pressure). Conclusions: Guided by an original evidence-based design framework, this study successfully developed and evaluated a customized MCI-specific VR exergame. Unlike existing research, this work highlights how multidisciplinary co-design and culturally familiar sport themes can optimize digital rehabilitation. It brings to the field of gerontechnology a replicable development workflow and vital mixed methods insights regarding the paradox between quantitative acceptability and qualitative physical discomfort driven by novelty.