Portable device allows monitoring Parkinson's symptoms at home

Npj Parkinson's Disease showed that a compact digital test, Quantitative Digitography (QDG), can provide a doctor with objective data on the motor symptoms of Parkinson's disease every day - right from the patient's home. For 30 seconds, a person alternately presses two spring-loaded levers, and the algorithm collects real, quantitative metrics of speed, amplitude, rhythm, etc., reducing them to a QDG Mobility Score (0-100; ≥92 is normal). Such monitoring closes the "gap" between rare visits, where the patient's memory and subjective scales are usually relied upon. Moreover, the system is integrated into the EHR and has already received the FDA's Breakthrough Device status.

Background of the study

Parkinson's disease is a chronic, undulating disease: within one day, the patient's speed and amplitude of movements may change, tremors and "freezing" may appear and disappear, and gait may fluctuate. In real practice, the doctor sees only rare "snapshots" of the condition - visits once every few months and subjective scales that depend on the patient's memory and the time of taking medications. Such "sparse" monitoring makes it difficult to accurately titrate therapy and leaves some problems unaddressed between visits.

An attempt to close this gap is diaries and wearables. But diaries are imprecise and labor-intensive, and wearables produce massive amounts of “black box” data: interpretation is unclear, it is difficult to integrate into clinical workflow, and compliance suffers (battery, straps, interfaces). Clinics need a tool that provides objective, reproducible motor metrics, can be done at home in minutes, and is easily mapped to everyday function.

Quantitative finger digitography is exactly that: short, serial presses allow us to calculate the speed, amplitude, and rhythm of movements, hand asymmetry, the “sequence effect,” and markers of freezing episodes. If such a test is done daily and remotely, the doctor gets a trajectory of symptoms in relation to the time of levodopa intake, on/off “windows,” and DBS settings - and can change the dose more accurately between visits. For the patient, this is a chance for a more stable day without the “roller coaster.”

For this approach to take hold, three conditions are important: high convenience/adherence (literally 30 seconds from home), reliable metrics (reproducibility and connection to functional scales), and integration into the EHR with a clear summary score for quick assessment. Then digital monitoring becomes not “gamification” but part of standard care - especially valuable where access to a movement disorder specialist is limited.

What did they do?

• A 30-day remote observation was conducted in patients with suspected Parkinsonism and with an established diagnosis (from “prediagnosis” to 20 years of illness).
• The main goal is compliance: will it be possible to perform at least 1 test per day in ≥16 out of 30 days (a threshold that is also important for reimbursement under RPM codes).
• Additionally, the following were assessed: convenience, reliability (test-retest), relationship of QDG with daily functionality (ADL, MDS-UPDRS II) and sensitivity to minor adjustments to therapy.

Main results

• 100% of participants completed the minimum 16/30 days; average adherence was 96.2% for 1 test/day and 82.2% for 2 tests/day (morning "off" and "on" on dopaminergics). Most rated the test as "easy".
• The QDG Mobility Score was consistently correlated with ADL (MDS-UPDRS II): ρ = −0.61; the better the QDG score, the fewer limitations in everyday life.
• Reliability is excellent: ICC > 0.90 in test-retest analyses.
• The QDG tracked a range of progression from the first hints (asymmetry and 'sagging' of one arm before diagnosis) to the phenomenon of succession and freezing episodes in the later stages.

What does this look like in a patient's life?

Smartphone + compact device with two levers (KeyDuo): sit comfortably, connect Bluetooth, and on command from the app, quickly and evenly “click” the index and middle fingers for 30 seconds (right hand, then left). The data goes to the cloud, the doctor sees the motor trajectory, the time relative to taking medications and DBS, and can change doses between visits. And all this is recorded in the EHR in real time.

• What exactly is measured:
  • speed/frequency/amplitude of movements;
  • variability and rhythm;
  • asymmetry of the hands and “dissociation of the fingers”;
  • sequence effect features and freezing moments.
    These metrics are summarized in the QDG Mobility Score and individual sub-indicators.

Why does this close the aid gap?

Today, many patients visit a neurologist once every 3-6 months, the MDS-UPDRS III scale is subjective and labor-intensive, and between visits the patient often has to "adjust" the doses. Remote objective monitoring gives the doctor "film between frames" to fine-tune therapy and reduce the risk of under-/overtreatment, falls and hospitalizations. At the same time, the threshold of 16/30 days of testing required by CMS for reimbursement under RPM codes was met by all in the study - this is an important argument in favor of scaling.

• Who will benefit most:
  • “borderline” cases at the pre-diagnosis stage (we catch early asymmetry and progress before the visit);
  • patients with fluctuations and on/off “windows”;
  • people on DBS, where it is important to see small shifts;
  • those who have limited access to a neurologist.

What is important to remember (limitations)

• The sample for analysis was 25 who completed 30 days; this is not an RCT or a head-to-head comparison with the standard of care.
• Despite the high ICC, the limits of agreement for the QDG Mobility Score were wide (±24 points) - it is important for clinicians to look at the dynamics and context, not just one single point.
• There were technical difficulties (Bluetooth, travel), some participants dropped out early; however, by the 2nd week everyone had mastered the protocol.

What's next?

• Integrating QDG into pragmatic trials: will 'monitoring + rapid correction' result in fewer falls/hospitalisations vs standard of visits?
• Develop personalized rules for “when and how to change therapy” based on QDG curves.
• Expand interoperability: SMART-on-FHIR dashboards are already live, but need to be scaled across healthcare systems.

Summary

The QDG is an accessible, objective, and home-based test that, with high compliance, gives the physician what was sorely lacking before: a daily picture of motor function between visits. It correlates with daily function, is sensitive to small “knob turns” in therapy, and is technically ready for widespread implementation. For patients, it is a chance for more stable days without the “roller coaster” of doses and symptoms.

Source: Negi AS et al. Remote real time digital monitoring fills a critical gap in the management of Parkinson's disease. npj Parkinson's Disease. Published August 12, 2025. https://doi.org/10.1038/s41531-025-01101-0