Discrete Cosine Transform for the Analysis of Essential Tremor

Abstract

Essential tremor (ET) is the most common movement disorder. In fact, its prevalence is about 20 times higher than that of Parkinson's disease. In addition, studies have shown that a high percentage of cases, between 50 and 70%, are estimated to be of genetic origin. The gold standard test for diagnosis, monitoring and to differentiate between both pathologies is based on the drawing of the Archimedes' spiral. Our major challenge is to develop the simplest system able to correctly classify Archimedes' spirals, therefore we will exclusively use the information of the x and y coordinates. This is the minimum information provided by any digitizing device. We explore the use of features from drawings related to the Discrete Cosine Transform as part of a wider cross-study for the diagnosis of essential tremor held at Biodonostia. We compare the performance of these features against other classic and already analyzed ones. We outperform previous results using a very simple system and a reduced set of features. Because the system is simple, it will be possible to implement it in a portable device (microcontroller), which will receive the x and y coordinates and will issue the classification result. This can be done in real time, and therefore without needing any extra job from the medical team. In future works these new drawing-biomarkers will be integrated with the ones obtained in the previous Biodonostia study. Undoubtedly, the use of this technology and user-friendly tools based on indirect measures could provide remarkable social and economic benefits.

A Mobile Application for Smart Computer-Aided Self-Administered Testing of Cognition, Speech, and Motor Impairment

“…Recently, many works have focused on providing digital cognitive and motoric function self-assessment tests on electronic consumer devices, such as smartphones [8], tablets [9], and dedicated graphical tablets [10]. Commonly implemented tests include Archimedes spiral drawing tasks [11][12][13][14][15][16][17], finger tapping [9], freehand drawing tasks [17], and tracing tasks [12,17].…”

“…Commonly implemented tests include Archimedes spiral drawing tasks [11][12][13][14][15][16][17], finger tapping [9], freehand drawing tasks [17], and tracing tasks [12,17]. The methods used to analyze the collected spatiotemporal finger tapping, finger drawing, or pen path data include statistical analysis [11,12,15], discrete cosine transform (DCT) features [10], entropy, and fractal dimension analysis [13].…”

Analysis of Fine Motor Skills in Essential Tremor: Combining Neuroimaging and Handwriting Biomarkers for Early Management

“…As part of a larger cross-sectional study for characterizing ET, our group has previously demonstrated how nonlinear biomarkers from handwriting (Lopez-de-Ipina et al, 2016 , 2018 ) can be used as a tool for developing an automatic classification of ET toward early diagnosis. Additionally, Solé-Casals et al ( 2019 ) demonstrated how new biomarkers from drawings and handwriting can be utilized from discrete cosine transformations (DCT).…”

“…This overactivity could appear in motor control trajectory, pressure, and/or their combinations. Thus, tracking these subtle differences in phenotype could be useful for early detection and correlation with brain structural changes ( Figure 1 ; Lopez-de-Ipina et al, 2018 ; Solé-Casals et al, 2019 ).…”

Computerized Screening of Essential Tremor and Level of Severity Using Consumer Tablet

“…Simple pen and paper tests are often performed in the clinic, both as a diagnostic aid for ET and as a rough measure of severity for monitoring purposes [4]. Computerized methods using digital tablets [5]- [12] or wearable sensors [13]- [17] have potential as sensitive and quantitative assessments of writing and drawing in ET. This could augment, or even outperform, the standard clinical tools for tremor grading, and would be of particular use in clinical trials of pharmacological treatments of ET.…”