Browsing by Author "Chen, Yu-Jung"

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A digital assessment system for evaluating kinetic tremor in essential tremor and Parkinson's disease
(2018-03-09)
Lin, Po-Chieh
;
Chen, Kai-Hsiang
;
Yang, Bing-Shiang
;
Chen, Yu-Jung
;
機械工程學系
Background: Spiral drawing on papers is a common tremor evaluation tool for diagnosing patients with essential tremor (ET) or Parkinson's disease (PD). No standard drawing methods and parameters that use graphic tablets are yet available for objective evaluation. Methods: This study established a tremor assessment system for tremor severity by using graphic tablets. Twelve patients with ET and twelve patients with PD were tested to establish system algorithms, and six additional patients were tested with the developed system to evaluate its performance. The patients also performed spiral drawing with three guiding paradigms on a graphic tablet: traced along a given spiral (S1), performed freehand drawing (S2), and traced along a guiding point (S3). Three parameters were calculated to quantify tremor severity: the means of radial difference per radian(|dr/d theta|), the means of radial difference per second (|dr/dt|), and the area under curve (AUC) of the frequency spectrum of the velocity. Each patient's drawing was also evaluated using a visual rating scale (VRS) by experienced physicians. The interrater reliability was examined to identify the most consistent test paradigm. Results: The parameter |dr/d theta| and AUC correlated well with the VRS (R > 0.8) in S1, S2 and S3 tests. The S1 test presented the best interrater reliability (Weighted Kappa coefficient, k = 0.80) among three tests. The Weighted Kappa coefficients are 0.67 and 0.71 in S2 and S3 tests, respectively. Conclusions: We developed three different guiding paradigms for spiral drawing on a digital graphic tablet for clinical tests. Three parameters were calculated to represent the tremor severity in spiral drawing and used to quantify temporal and spatial characteristics of tremor, and provided good correlation with current clinical assessments. The test "traced along a given spiral" is recommended due to its good interrater reliability.
Development of method for quantifying essential tremor using a small optical device
(2016-06-15)
Chen, Kai-Hsiang
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Lin, Po-Chieh
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Chen, Yu-Jung
;
Yang, Bing-Shiang
;
Lin, Chin-Hsien
Background: Clinical assessment scales are the most common means used by physicians to assess tremor severity. Some scientific tools that may be able to replace these scales to objectively assess the severity, such as accelerometers, digital tablets, electromyography (EMG) measurement devices, and motion capture cameras, are currently available. However, most of the operational modes of these tools are relatively complex or are only able to capture part of the clinical information; furthermore, using these tools is sometimes time consuming. Currently, there is no tool available for automatically quantifying tremor severity in clinical environments. New method: We aimed to develop a rapid, objective, and quantitative system for measuring the severity of finger tremor using a small portable optical device (Leap Motion). Results: A single test took 15 s to conduct, and three algorithms were proposed to quantify the severity of finger tremor. The system was tested with four patients diagnosed with essential tremor. Comparison with existing method: The proposed algorithms were able to quantify different characteristics of tremor in clinical environments, and could be used as references for future clinical assessments. Conclusions: A portable, easy-to-use, small -sized, and noncontact device (Leap Motion) was used to clinically detect and record finger movement, and three algorithms were proposed to describe tremor amplitudes. (C) 2016 Elsevier B.V. All rights reserved.
Heterostructured ferromagnet-topological insulator with dual-phase magnetic properties
(2018-01-01)
Chang, Shu-Jui
;
Chuang, Pei-Yu
;
Chong, Cheong-Wei
;
Chen, Yu-Jung
;
Huang, Jung-Chun Andrew
The introduction of ferromagnetism at the surface of a topological insulator (TI) produces fascinating spin-charge phenomena. It has been assumed that these fascinating effects are associated with a homogeneous ferromagnetic (FM) layer possessing a single type of magnetic phase. However, we obtained phase separation within the FM layer of a Ni80Fe20/Bi2Se3 heterostructure. This phase separation was caused by the diffusion of Ni into Bi2Se3, forming a ternary magnetic phase of Ni:Bi2Se3. The inward diffusion of Ni led to the formation of an FeSe phase outward, transforming the original Ni80Fe20/Bi2Se3 into a sandwich structure comprising FeSe/Ni:Bi2Se3/Bi2Se3 with dual-phase magnetic characteristics similar to that driven by the proximity effect. Such a phenomenon might have been overlooked in previous studies with a strong focus on the proximity effect. X-ray magnetic spectroscopy revealed that FeSe and Ni:Bi2Se3 possess horizontal and perpendicular magnetic anisotropy, respectively. The overall magnetic order of the heterostructure can be easily tuned by adjusting the thickness of the Bi2Se3 as it compromises the magnetic orders of the two magnetic phases. This discovery is essential to the quantification of spin-charge phenomena in similar material combinations where the FM layer is composed of multiple elements.
Identification of a Simplest Hypervalent Hydrogen Fluoride Anion in Solid Argon
(2017-06-07)
Liu, Meng-Chen
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Chen, Hui-Fen
;
Chin, Chih-Hao
;
Huang, Tzu-Ping
;
Chen, Yu-Jung
Hypervalent molecules are one of the exceptions to the octet rule. Bonding in most hypervalent molecules is well rationalized by the Rundle-Pimentel model (three-center four-electron bond), and high ionic bonding between the ligands and the central atom is essential for stabilizing hypervalent molecules. Here, we produced one of the simplest hypervalent anions, HF-, which is known to deviate from the Rundle-Pimentel model, and identified its ro-vibrational features. High-level ab inito calculations reveal that its bond dissociation energy is comparable to that of dihalides, as supported by secondary photolysis experiments with irradiation at various wavelengths. The charge distribution analysis suggested that the F atom of HF-is negative and hypervalent and the bonding is more covalent than ionic.
The difference in visuomotor feedback velocity control during spiral drawing between Parkinson's disease and essential tremor
(2018-06-01)
Chen, Kai-Hsiang
;
Lin, Po-Chieh
;
Yang, Bing-Shiang
;
Chen, Yu-Jung
;
機械工程學系
In a spiral task, the accuracy of the spiral trajectory, which is affected by tracing or tracking ability, differs between patients with Parkinson's disease (PD) and essential tremor (ET). However, not many studies have analyzed velocity differences between the groups during this task. This study aimed to examine differences between the groups related to this characteristic using a tablet. Fourteen PD, 12 ET, and 12 control group participants performed two tasks: tracing a given spiral (T1) and following a guiding point (T2). A digitized tablet was used to record movements and trajectory. Effects of direct visual feedback on intergroup and intragroup velocity were measured. Although PD patients had a significantly lower T1 velocity than the control group (p < 0.05), they could match the velocity of the guiding point (3.0 cm/s) in T2. There was no significant difference in the average T1 velocity between ET and the control groups (p = 0.26); however, the T2 velocity of ET patients was significantly higher than the control group (p < 0.05). They were also unable to adjust the velocity to match the guiding point, indicating that ET patients have a poorer ability to follow dynamic guidance. When both groups of patients have similar action tremor severity, their ability to follow dynamic guidance was still significantly different. Our study combined visual feedback with spiral drawing and demonstrated differences in the following-velocity distribution in PD and ET. This method may be used to distinguish the tremor presentation of both diseases, and thus, provide accurate diagnosis.