Design and Development of an Android App (HanDex) to Enhance Hand Dexterity in Children With Poor Handwriting

According to the oscillation theory of handwriting, letters are formed by the coupled modulation of horizontal and vertical oscillations of the hands. This modulation-oscillation scheme requires human motor control. Hence, one of the reasons for poor handwriting is a lack of fine motor skills. The main objective of this study was to design, develop, and evaluate a hand therapeutic application (HanDex) for children with writing difficulties to enhance their hand dexterity. This paper describes the design, development, and evaluation of the HanDex app. It has mainly six activities for improving tripod grip, hand-eye coordination, spatial organization, letter formation, and fine motor skills. The main principle underlying the design of these activities is the oscillation theory of handwriting. A set of user interface (UI) guidelines have been followed in the UI design for simplicity, user motivation, easy navigation, etc. User evaluation of the prototype was conducted by ten participants in five iterations, and the final product was built by considering their feedback. Subsequently, we conducted case studies on two primary school children with poor handwriting skills to test the effectiveness of the application. This study used a single-subject pretest-posttest design to observe and measure the efficacy of the HanDex application. The posttest results showed a positive impact on letter formation, size of letters, spacing of letters and words, placement, speed, and legibility in these children. Hence, the HanDex app is promising and warrants further investigation in more children with different levels of handwriting difficulty.