Quantitative Parkinson's Disease Rigidity Measurement System

The absence of a remote, reliable measure of rigidity, bradykinesia and tremor is a major limitation for telemedicine and multicenter clinical trials in Parkinson's disease (PD). Addressing this need, Stanford researchers have invented a device and process for simple, quantitative, and remote evaluation of rigidity, bradykinesia and tremor through the analysis of presses and releases of adjacent tensioned engineered levers that measure amplitude with submillimeter accuracy and timing of lever displacement, Figure 1. Repetitive alternating pressing and releasing with the index and middle fingers on this engineered, Bluetooth connected digitography device enables a remote, reliable and objective assessment of cardinal motor signs in PD.

Figure

Figure 1 - Upper panel: photo of a digitography device with the index and middle fingers placed on the levers. Lower panel: example of alternating full amplitude presses and releases by the adjacent fingers over time. Each finger is denoted by red or blue trace respectively. The press and release phases are labelled with arrows. The y-axis is amplitude; the x-axis is time. The interstrike insterval (ISI) is the time it takes to complete a full cycle of the task with one finger.

Image Credit: H Bronte-Stewart presentation; photo from stock

Stage of Development

Prototyped a compact, personalized Bluetooth enabled digitographic measuring device, Figure 1

Demonstrated that the key release speed was a robust quantitative measure of upper extremity rigidity in individuals with PD

Demonstrated four measures of bradykinesia (frequency, amplitude, press speed, and variability of amplitude and frequency)

Demonstrated measures of rest and action tremor

Validated all measures of rigidity, bradykinesia, and tremor with the standard clinical rating scale the MDS-UPDRS III

Demonstrated the measure of freezing in upper limb movements in QDG