Finger Tapping Test Evaluated by Embedded Fiber Bragg Gratings

The finger tapping (FT) test is a widely used neuropsychological assessment designed to measure fine motor skills, like speed and coordination of finger movements, particularly used in diagnosing and tracking neurological conditions that affect motor control. Nowadays, despite the spread of this test, FT is clinically evaluated by observing the patient executing several FT tasks (FTTs) and assigning a score to the FT performance based on rating scales, depending on the specific pathology to be diagnosed. Hence, there is a need for a device that supports clinicians in evaluating the execution of the FTTs for specific patients by providing quantitative information. Therefore, this work presents a novel FT sensor based on fiber Bragg grating (FBG) and its embedding in flexible and wearable compounds. The proposed sensor consists of a fiber Bragg grating (FBG) embedded in a silicone thimble that can be easily worn during functional tests (FTs). This design is flexible, lightweight, and minimally invasive, effectively overcoming the challenges posed by other devices discussed in the literature. The developed FBG thimble has been tested on eight volunteers during three different FTTs, i.e., random, synchronized, and quick tapping (QT), performed using both hands to record and compare the FT waveforms by varying subject, hand, and kind of movement. The sensor has proved to be able to measure the tapping signals in real time and provide information about several FT parameters of clinical interest, such as force touch, rhythmicity, and motor coordination. Moreover, the spectral analysis of the recorded signals has been carried out to compare the subjects' recordings for each FTT, highlighting the differences among them in terms of movement periodicity and regularity.