Table 3 Categories of digital biomarkers.

Susceptibility and risk biomarker

A biomarker that indicates the potential for developing a disease or medical condition in an individual who does not currently have clinically apparent disease or medical condition.

^aDetect cognitive changes in healthy subjects at risk of developing Alzheimer’s disease using a video game platform¹³⁹.

Diagnostic biomarker

A biomarker used to detect or confirm the presence of a disease or condition of interest or to identify individuals with a subtype of the disease.

^aDiagnose ADHD in children using eye vergence metrics¹⁴⁰.

^aDetect depression and Parkinson’s disease using vocal biomarkers¹⁴¹.

^aDiagnose asthma and respiratory infections using smartphone-recorded cough sounds¹⁴².

Monitoring biomarker

A biomarker measured serially for assessing the status of a disease or medical condition or for evidence of exposure to (or effect of) a medical product or an environmental agent.

^aQuantify Parkinson’s disease severity using smartphones and machine learning¹⁴³.

^bTrack time and location of short-acting beta-agonist inhaler use through an attached wireless sensor¹⁴⁴.

^aDetection of nocturnal scratching movements in patients with atopic dermatitis using accelerometers and recurrent neural networks¹⁴⁵.

^bMeasurements of sympathetic nervous impulses at the skin and inference of parasympathetic activity from heart rate variation to detect tonic-clonic epileptic seizures and immediately alert care providers¹⁴⁶.

^bPortable electrocardiogram sensor associated to a smartphone app to monitor atrial fibrillation, bradycardia, tachycardia or normal heart rhythm and inform the clinician¹⁴⁷.

^aMeasure adherence in treatment of schizophrenia and bipolar disorder with an ingestible digital pill¹⁴⁸.

Endpoint digital biomarkers in clinical trials

Endpoints generated by the use of mobile technologies in clinical setting.

^aAccelerometer-derived motor abnormalities for use in Parkinson’s disease⁴⁷.

^bMonitoring of multiple sclerosis patients with digital technologies by using active and passive tests (ClinicalTrials.gov Identifiers: NCT03523858; NCT02952911)

^bVirtual Reality Functional Capacity Assessment Tool as co-primary and secondary endpoint in schizophrenia and major depressive disorder¹³⁹.