Better4All Personalized Intervention Pilot Study

The BETTER4All Pilot Study is a multicenter, longitudinal, observational study designed to assess the usability, feasibility, and acceptability of the BETTER4U App and BETTER4U Intervention Platform, both of which integrate real-time behavioral monitoring and artificial intelligence (AI)-driven decision support tools. Conducted in seven European countries (Cyprus, France, Greece, Poland, Portugal, Spain, and Sweden), the study includes approximately 490 adult participants split into two groups: (a) "end-users" from the general population, who will use wearable devices and the mobile App for 21 days, and (b) "implementers," healthcare professionals who will test the intervention platform for 7 days using synthetic and self-recorded data.

The BETTER4U system employs Bluetooth Low Energy (BLE) smartwatches for passive data collection, including accelerometer signals, heart rate variability, sleep structure, and geolocation data. Data from the wearables and smartphone sensors are processed using AI and machine learning algorithms to derive behavioral indicators such as physical activity, eating, sleep patterns (termed BETTER4U Core Behavioral Indicators - BCBIs), and contextual environmental factors (Living Environment Indicators - LEIs). These indicators are calculated both locally and on secure servers via structured data pipelines, ensuring privacy and GDPR compliance.

Data collection comprises three sources: (1) passively collected wearable/App data, (2) online questionnaires via RedCap (e.g., IPAQ, GAD-2, PHQ-2, EQ-5D-5L, PSQI, Mini-EAT), and (3) "ground truth" data logged by implementers to validate algorithmic outputs. Engagement metrics, such as app usage duration and feature interaction frequency, are also automatically recorded. Feedback on usability and feasibility is collected via validated tools, including the System Usability Scale (SUS), MAUQ, AIM, IAM, and FIM.

The primary technical aim is to verify and refine the causal AI models developed in earlier project phases (WP5), ensuring the system is optimized for personalized intervention delivery in the upcoming BETTER4ALL randomized controlled trial (WP7).

Inclusion criteria

• Age: Participants aged 18-65 years to represent the adult general population.
• Body Mass Index (BMI):

• Overweight or obesity group: BMI ≥ 25 kg/m².
• Normal weight group: BMI 18.5-24.9 kg/m².
• Technology Use:

• Willingness and ability to use wearable devices and an Android mobile application for the duration of the study.
• Owning a smartphone device with the Android operating system.
• Eating utensil technique: dominant hand gestures that correspond to handling of food via a fork or a spoon.
• Language Proficiency: Ability to read and understand the language in which the mobile app and study materials are provided.
• Consent: Willing to provide informed consent to participate in the study.
• Residency: Must be a resident of one of the seven participating countries.
• Availability: Able to participate for the full three-week duration of the study and comply with the study protocol.

Exclusion criteria

• Health Conditions: Pregnant or breastfeeding women, as they might have different lifestyle behaviours or health needs.
• Physical Limitations: Any physical or mental condition that would prevent the participant from using the wearable device or mobile application as intended.
• Eating utensil technique: eating food with chopsticks on a daily or regular basis.
• Technical Incompatibility: Individuals who do not own a compatible smartphone or are unable to use the provided wearable devices for technical reasons.