Quantifying upper limb tremor in people with multiple sclerosis using Fast Fourier Transform based analysis of wrist accelerometer signals. (December 2020)

• Record Type: Journal Article
• Authors: Teufl, Stefan; Preston, Jenny; van Wijck, Frederike; Stansfield, Ben
• Is Part Of: Journal of rehabilitation and assistive technologies engineering. Volume 7(2020)
• Publication Date: 2020-12
• Subjects: Multiple sclerosis -- tremor -- wrist accelerometer sensor -- Fast Fourier Transform analysis -- algorithm development; Rehabilitation technology -- Periodicals; 617.03
• DOI: 10.1177/2055668320966955
• Languages: English
• ISSNs: 2055-6683

Abstract

Introduction: Tremor is a disabling symptom of Multiple Sclerosis (MS). The development of objective methods of tremor characterisation to assess intervention efficacy and disease progression is therefore important. The possibility of using a Fast Fourier Transform (FFT) method for tremor detection was explored. Methods: Acceleration from a wrist-worn device was analysed using FFTs to identify and characterise tremor magnitude and frequency. Processing parameters were explored to provide insight into the optimal algorithm. Participants wore a wrist tri-axial accelerometer during 9 tasks. The FAHN clinical assessment of tremor was used as the reference standard. Results: Five people with MS and tremor (57.6 ± 15.3 years, 3 F/2M) and ten disease-free controls (42.4 ± 10.9 years, 5 M/5F) took part. Using specific algorithm settings tremor identification was possible (peak frequency 3–15Hz; magnitude greater than 0.06 g; 2 s windows with 50% overlap; using 2 of 3 axes of acceleration), giving sensitivity 0.974 and specificity 0.971 (38 tremor occurrences out of 108 tasks, 1 false positive, 2 false negatives). Tremor had frequency 3.5–13.0 Hz and amplitude 0.07–2.60g. Conclusions: Upper limb tremor in people with MS can be detected using a FFT approach based on acceleration recorded at the wrist, demonstrating the possibility of using this minimally encumbering technique within clinical practice.