Wearable technology for objective symptom assessment

Today, Parkinson's disease (PD) symptoms are primarily evaluated based on subjective assessments during in-clinic visits using rating scales like the Unified Parkinson’s Disease Rating Scale (UPDRS). These are typically 20- to 30-minute clinic appointments, where the clinician questions the patients about their symptoms and overall well-being while observing the patient and carrying out a physical examination. This approach, however, has specific limitations, leading to often incomplete disease progression evaluation. In-clinic evaluations only capture a “snapshot” of the symptoms at a specific moment in time. In addition, the evaluations are highly subjective.

Lately, the need for objective measurement to assess PD symptoms and treatment efficacy has emerged. Clinical assessment will continue to be essential in the diagnosis and treatment of PD, but also modern technology, including wearable devices and artificial intelligence, will play a crucial role in the early detection of the disease and improving treatment effectiveness.

Over the last decades, different methods have been developed to enable the objective measurement of PD motor symptoms.

Wearable devices with motion measurement

Wearable devices with motion measurement provide a non-invasive method to measure the movements of PD patients. The method uses dedicated devices with inertial measurement units (IMU) or accelerometer data from a smartwatch to quantify physical movements when assessing a patient’s symptoms. The devices are easy to wear and allow physical movement data to be captured unobtrusively during the patient’s daily life.

The patient's movements are measured with one or several sensors at regular intervals, with the measurement also including voluntary movement and movement caused by external sources. To capture accurate data for symptom analysis, a measurement time between 6-10 days is recommended.

Wearable devices with motion measurement can assess different motor symptoms of PD, such as dyskinesia, bradykinesia, tremor, and gait impairment. Despite offering objective data on the patient's physical movements, they are not able to capture motor symptoms that are not yet visible or physically apparent, such as internal tremors. In addition, they are not able to identify the root cause of the movement.

Wearable devices with EMG and motion measurement

Wearable devices with surface electromyography (EMG) and motion measurement add the measurement of neuromuscular signals to motion measurement for deeper insight into muscle activity. EMG measures the electrical muscle activity causing a person’s movement, detecting issues with motor coordination, motor nerves, muscles, and the communication between them. It is used to objectively evaluate the different motor symptoms of PD, such as tremor, rigidity, and bradykinesia, and indicates how the disease modifies the muscle activity patterns during rest periods or different types of movement.

The small, non-invasive measurement device is worn during the day and night for a selected period, usually 1-3 days, to provide a comprehensive overview of the symptoms and track possible differences in symptom behavior.

With EMG and motion measurement, it is possible to separate symptoms from voluntary and externally caused movements, differentiate between visually similar symptoms, detect and measure rigidity as well as differentiate side effects, and detect symptoms not yet physically visible.

By cross-validating the findings between the two technologies – EMG and kinematic measurement, more meaningful and holistic clinical insight can be provided for therapeutic decision-making and treatment planning.

Modern technology for improved patient outcomes

Wearable devices with either motion measurement or EMG and motion measurement are intended to complement the clinical assessment and help clinicians get a more holistic view of a patient’s condition by collecting data over a more extended period of time and at home. The measurement in a familiar in-home environment allows to best capture the patient’s day-to-day condition, including fluctuations.

In addition, regular assessments of the patient’s symptoms through wearable technology allow clinicians to identify patterns and trends and better understand the progression of the disease. Regular measurement also helps clinicians to objectively monitor the treatment's effectiveness and maintain a better care balance for the patient.

Studies show that continuous monitoring plays a crucial role in the treatment quality a patient receives by allowing medical professionals to better track disease progression and adjust medication. Additionally, continuous monitoring with wearable devices significantly reduces healthcare system costs and raises patient satisfaction.