Finger tapping quantitative measurement via an ultrasound contactless device

Neurodegenerative diseases are often linked to the gradual loss of neurons and synaptic connections, typically occurring in the elderly. These diseases are distinguished by specific symptoms, which depend on the location of neuronal loss in the brain. Focusing on Parkinson’s Disease, the typical symptoms include bradykinesia, tremors, and upper limb rigidity. Currently, clinicians assess bradykinesia visually by observing finger tapping hand gestures and rating the severity qualitatively. In healthy subjects, finger movement remains stable in terms of both rate and displacement. However, neurodegenerative patients exhibit instability in gesture execution due to the symptoms mentioned above. In this context, an ultrasound system for monitoring finger tapping has been proposed. By exploiting the Doppler effect caused by finger movement, the system can estimate the velocity of the finger. With appropriate signal processing, it can also determine tap rate and finger displacement, providing quantitative support for clinicians. The prototype has been tested with volunteers, showing promising results.