Commercially available products for the digital tracking of biomarkers in Parkinson's Disease

• Biomarkers of Parkinson’s disease are needed for differential diagnosis and earlier treatment. • Wearable devices and smartphone applications have potential to identify biomarkers of Parkinson’s disease. • Current products capture early motor dysfunction through upper limb and eye movements. Parkinson’s Disease (PD) is a debilitating neurological disorder which affects 8.5 million people globally. Diagnosis of PD is made upon presentation of motor symptoms. However, there is a well-recognised prodromal phase of PD, when patients experience non-motor symptoms, and subtle motor symptoms, before the onset of the cardinal motor symptoms. Biomarkers of this prodromal phase can provide a diagnostic window into early disease processes, assisting with differential diagnosis of PD and enabling earlier treatment. Due to increased availability of commercially-available products, both wearable devices and smartphone applications are being explored for potential to identify PD biomarkers. Such products can provide clinicians with early warning of disease progression, and supply researchers with tools for monitoring PD outside of laboratory settings. This systematic review critically examined the academic literature published in the English language to identify currently-available products designed to track biomarkers of PD across 6 databases between January 2000 and March 2025. 27 papers were identified which captured physiological biomarkers in PD patients using commercially-available products. Current products emphasize the capture of early motor dysfunction through both upper limb and eye movements. There is a lack of literature on the validation of commercially-available products for the detection of PD, despite an increase in advanced data analysis algorithms. There is a critical need for validation of devices for the tracking of biomarkers of PD, which may be utilised for detection during the prodromal phase.