The study presents the creation and validation of a tool for evaluating gastrointestinal health in Rett syndrome patients (RTT). The Gastrointestinal Health Questionnaire (GHQ) was expected to be a meaningful clinical outcomes measure of gastrointestinal health in RTT. The study utilised parent interviews, questionnaires, and a literature review to create a questionnaire for people with RTT on their gastrointestinal health and function, mood and behaviours, and parental concerns. Parents of affected and unaffected persons took the GHQ, appraised the relevance and value of items, and completed 5 questionnaires on gastrointestinal health, child-related mood and behaviours, and parent concerns. To investigate the GHQ’s validity, the researchers performed multivariate item analysis, 2-sample t tests, and correlations. In the GHQ, they found satisfactory internal consistency of claims on gastrointestinal health and function, RTT-related mood and behaviours, and parent concerns. They found acceptable external validity based on variations in response scores between affected and unaffected parents, as well as correlations in parental response scores between the GHQ and five validated questionnaires addressing comparable topics.

The GHQ is a viable measure for assessing gastrointestinal health in RTT, and it allows for field testing the safety and efficacy of innovative pharmacological therapies.