Spectral parameters for finger tapping quantification

Abstract

A miniature inertial sensor placed on fingertip of index finger while performing finger tapping test can be used for an objective quantification of finger tapping motion. Temporal and spatial parameters such as cadence, tapping duration, and tapping angle can be extracted for detailed analysis. However, the mentioned parameters, although intuitive and simple to interpret, do not always provide all the necessary information regarding the subject's motor performance. Analysis of frequency content of the finger tapping movement can provide crucial information about the patient's condition. In this paper, we present parameters extracted from spectral analysis that we found to be significant for finger tapping assessment. With these parameters, tapping's intra-variability, movement smoothness and anomalies that may occur within the tapping performance can be detected and described, providing significant information for further diagnostics and monitoring progress of the disease or response to therapy.

An Expert System for Quantification of Bradykinesia Based on Wearable Inertial Sensors

“…Hesitations and freezes are manifested as irregularities or breaks of the tapping rhythm that may occur in different moments of the tapping performance and represent an important part of the finger-tapping evaluation. The continuous wavelet transform (CWT) was applied for the detection and localization of disruptions of the tapping rhythmicity [28]. It is a time-frequency analysis method that is suitable for the analysis of transient changes and spikes in rhythmic behaviour [29].…”

“…The obtained characteristic was normalized with respect to its maximum value and is expressed as a percentage (CSAT (%)). In this way, we obtain a characteristic that describes the temporal changes in the tapping activity [28]. An example of the CSAT characteristic for one patient is presented in Figure 5, lower panel.…”