F029 Digital-HD: smartphone and smartwatch-based testing to assess the motor, cognitive, and behavioural symptoms of Huntington’s disease

<h3>Background</h3> HD symptoms are primarily assessed during clinical or in-person research visits, which typically occur infrequently. This approach fails to capture day-to-day changes in disease burden for patients and relies on clinically administered tests which are subject to intra and interrater variability and lower ecological validity. <h3>Aims</h3> Digital-HD was a longitudinal observational study which aimed to evaluate the feasibility, tolerability, and validity of smartphone and smartwatch-based testing to monitor HD symptoms. <h3>Methods/Techniques</h3> 120 participants were issued a smartphone and smartwatch pair and asked to complete behavioural, cognitive, and motor tasks on a custom-built Android app. These included: patient reported outcomes on mood, behaviour, and function; digitalised versions of the SDMT and SWR; Speeded Tapping, Draw-a-Shape, Chorea, Balance, U-turn, and Walking tasks. Additionally, participants underwent continuous passive monitoring of gait, chorea, and activity levels for up to 18-months. To assess the validity of the novel digital tasks, participants attended three in-clinic visits where they underwent additional testing using the currently employed clinical counterparts. <h3>Results/Outcome</h3> Baseline cross-sectional analysis indicated that the features derived from digital tasks had good psychometric properties when compared to standard clinical assessments. All motor assessments can differentiate between premanifest and manifest, and some, including Speeded Tapping, differentiate between control and premanifest as well. Longitudinal analysis at cohort level is challenging because adherence was severely impacted by COVID, but insights can be derived from individual patient progression profiles. <h3>Conclusions</h3> The findings provide further insight into the feasibility and validity of using smartphones and smartwatches to remotely study HD symptoms.