Introduction Longitudinal studies on the evolution of autism spectrum disorder (ASD) symptoms are limited and have primarily used repeated measurements performed several months apart. However, measurements of changes in everyday life should more closely reflect the ‘real life’ of the patient and his or her family. We propose to study the child's ASD symptoms and their effect on the quality of life, psychological status and anxiety of the child's parents over a 6-month period using SMARTAUTISM, a smartphone application.

Method and analysis This is a prospective, longitudinal, exploratory, open study with a 6-month follow-up period. Data will be recorded longitudinally over multiple weeks under natural conditions. The factors affecting the quality of life and anxiety of parents of children with ASD and the children's functional symptoms will be examined, and the feasibility of using a smartphone application designed for parents of ASD patients will be assessed. Primary objective: Explore the evolution of a child's behaviour over 6 months and the (psychological and social) effects of these changes on the family. Secondary objective: Assess the feasibility of our application by examining the filling rate and application usage by parents for 6 months. 100 families containing 1 child diagnosed with ASD will be included. At baseline, sociodemographic, psychiatric and medical data will be recorded. The correlations of the general epidemiological variables (primary outcome measure) will be evaluated via multivariate analysis. The application filling rate (relative to the ideal filling rate) will be used to assess the feasibility of the application (secondary outcome measure).

Ethics and dissemination The SMARTAUTISM study has the approval of the local ethics committee, and data security will be ensured via the use of encryption and a secure medical server. The use of this application will be proposed at autism resource centres across France.