The introduction of a new mobile lifestyle tool in the battle against hypothalamic obesity; the "HAPPYthalamus" application.

Background: Children with hypothalamic dysfunction may experience hypothalamic weight gain, marked by severe hyperphagia, low energy expenditure, and reduced initiative. We developed the mobile app "HAPPYthalamus" to support these children by promoting exercise, providing distraction from hyperphagia, and rewarding healthy behavior. This study evaluated the app's usability and patient satisfaction.

Methods: This was a non-randomized, explorative intervention study. Children (8-18 years) with hypothalamic dysfunction and a suprasellar brain tumor were included. Patients were instructed to use the mobile application (app) for six months. We applied a mixed-methods design evaluating app use and satisfaction through questionnaires and semi-structured interviews.

Results: Of 22 patients, 15 scored positive on learning to use the app. Positive effects on eating distraction were reported by 9 patients. The app was not well adapted to different age groups; some found the challenges motivating while others were indifferent to winning challenges and forgot the app due to limited variety. Overall, 64% of the children indicated the app should be part of the standard of care.

Conclusions: A mobile app as a lifestyle buddy for children with hypothalamic dysfunction is useable but needs improvements. Adapting to age groups and incorporating behavioral change theories, gamification, and reward systems could enhance engagement and support a healthier lifestyle.