Introduction: This study aimed to quantify the relationship between prosthetic users' emotional response to prosthesis aesthetics and specific product properties.

Methods: Words representing prosthesis users' emotional response (Kansei) to different aesthetic designs of prostheses were identified via interviews and mood boards. A group of experts consolidated the words into thematic groups, each represented by a single, high-level 'Kansei' word. 53 lower limb prosthesis users completed a questionnaire, rating their perception of 13 aesthetic designs using the 'Kansei' words. Quantification Theory Type 1 was applied to explore the relationship between words and product properties. Sub-analyses assessed for differences based on sex, age and level of extroversion.

Results: 5 high-level Kansei words were identified ('Natural', 'Technological', 'Cool', 'Unique' and 'Functional'). The Kansei word 'Natural' had a strong association with realistic looking prostheses while the words 'Technological', 'Cool' and 'Unique' were strongly associated with expressive designs which incorporate hard, colourful covers. The word 'Functional' was not a reliable predictor of product properties. No major differences were observed within sub-grouped categories.

Conclusion: Kansei words identified in this study can be used to help guide clients in their aesthetic design choices and to assist designers in achieving the desired response from their products.