Wearable Devices for Assessment of Tremor

Abstract

Tremor is an impairing symptom associated with several neurological diseases. Some of such diseases are neurodegenerative, and tremor characterization may be of help in differential diagnosis. To date, electromyography (EMG) is the gold standard for the analysis and diagnosis of tremors. In the last decade, however, several studies have been conducted for the validation of different techniques and new, non-invasive, portable, or even wearable devices have been recently proposed as complementary tools to EMG for a better characterization of tremors. Such devices have proven to be useful for monitoring the efficacy of therapies or even aiding in differential diagnosis. The aim of this review is to present systematically such new solutions, trying to highlight their potentialities and limitations, with a hint to future developments.

Keywords: Parkinson's disease; diagnosis; essential tremor; monitoring; tremor; wearable devices.

Figure 1

Electrophysiological and spectral characteristics of tremor patterns. Muscle bursts for (A) alternating and (B) synchronous tremor patterns; magnitude and phase cross-spectral diagrams for (C) alternating and (D) synchronous tremor patterns. (E) Wrist-worn device, with EMG plates and mobile app for the characterization of tremor patterns. Alternating bursts of antagonist muscles show a marked phase difference at peak tremor frequency, while synchronous bursts have a small phase difference at peak tremor frequency. In alternating tremors, peak amplitude is usually higher and average frequency is lower than in synchronous tremors. EMG, electromyography; CPSD, cross power spectral density.