User-Centered Design and Development of an Electric Nail Clipper for Individuals with Post-Stroke Hemiplegia

Individuals with post-stroke hemiplegia may experience difficulty performing independent nail care because conventional nail clippers require bilateral hand function, grip strength, and fine motor control. Despite its relevance to personal hygiene and independence, nail care remains underexplored in rehabilitation engineering. The aim of this study was to design and develop a user-centered electric nail clipper for individuals with post-stroke hemiplegia and evaluate the preliminary functional suitability of the finalized prototype under supervised conditions. A sequential mixed-methods, user-centered device-development study was conducted following ISO 9241-210 principles. Phase I involved 10 healthy volunteers who participated in semi-structured interviews and controlled prototype testing to identify preliminary operational, ergonomic, and safety considerations. Stroke-specific functional requirements were additionally informed by the clinical context, relevant literature, and subsequent evaluation in the intended user population. These inputs were translated into engineering requirements and four iterative prototype configurations, which were independently evaluated by a five-member multidisciplinary expert panel. In Phase II, the finalized prototype underwent supervised participant-based evaluation in 20 individuals with post-stroke hemiplegia. These participants constituted the same cohort previously reported in a randomized controlled trial; previously published comparative clinical outcomes were not analyzed as new findings in the present study. Five principal functional considerations informed prototype development: one-handed stabilization, reduced operating effort, controlled nail reduction, operational safety, and practical device handling and debris management. The finalized design incorporated a stabilized triangular tabletop structure, silicone suction base, motor-driven rotary filing mechanism, adjustable operating speed, removable buffing head, debris-collection compartment, LED illumination, and rechargeable power. Prototype 4 received the highest overall expert rating (mean = 4.43, SD = 0.48) and was selected for participant-based evaluation. Under short-term supervised conditions, participants with post-stroke hemiplegia were able to perform one-handed nail care using the finalized prototype, with no device-related adverse events or malfunctions observed. The study demonstrates a structured user-centered pathway for translating functional and contextual requirements into an assistive nail-care device for individuals with post-stroke hemiplegia. The finalized prototype showed preliminary functional suitability during short-term supervised use; however, these findings do not establish comparative clinical effectiveness, long-term safety, or performance during unsupervised use. Larger, longitudinal, and home-based studies incorporating objective performance measures and validated user-reported instruments are warranted.