This app is for the use of the researchers and participants of the NOAH clinical study at Imperial College London. The app was developed by the Brain & Behaviour Lab (https://faisallab.org/) at Imperial College London (Prof. Aldo Faisal). The research study has been approved by the Imperial College London research ethics committee (Health Research Authority IRAS Project ID: 251774). The app integrates with the health app (HealthKit) and collects the readings from the inertial measurement unit (IMU) sensor on the watch (which records the linear and rotational acceleration), the heart-rate sensor data (blood oxygen level, heart rate, heart rate variability), step count, distance walked, fall detection information and sends the data to a secure clinical research server for analysis. No other personal information is recorded. No data collected is shared with Apple or other third parties.