scholarly journals Accuracy of Smartphone Video for Contactless Measurement of Hand Tremor Frequency

2020 ◽  
Vol 8 (1) ◽  
pp. 69-75
Author(s):  
Stefan Williams ◽  
Hui Fang ◽  
Samuel D. Relton ◽  
David C. Wong ◽  
Taimour Alam ◽  
...  
Keyword(s):  
Contactless Measurement ◽  
Hand Tremor ◽  
Tremor Frequency

Involuntary ankle oscillations from normal subjects

1977 ◽  
Vol 233 (1) ◽  
pp. R8-R14
Author(s):  
R. N. Stiles ◽  
R. R. Rietz
Keyword(s):  
Spectral Analysis ◽  
Root Mean Square ◽  
Power Function ◽  
Normal Subjects ◽  
Displacement Amplitude ◽  
Mean Square ◽  
Hand Tremor ◽  
Negative Relation ◽  
Tremor Frequency

Spectral analysis of ankle tremor records obtained from normal seated subjects during continuous elevation of the heel for 10-45 min revealed that the root-mean-square (rms) displacement amplitude of the tremor increased from minimum values of about 4 micronm to values as large as 4,000 micronm. Associated with this increase in the displacement amplitude was a systematic decrease in the tremor frequency from values of 7-8 Hz to values of 5-6 Hz. Spectral analysis of demodulated soleus EMG records indicated that the rms value of this EMG (calculated at the tremor frequency) and the rms displacement of the tremor are related by a power function, with the rms value of the EMG increasing over a range of about 4-40 micronV as the tremor displacement increased from about 4 to 4,000 micronm. The negative relation between frequency and rms displacement amplitude values for postural ankle tremor was similar to that found previously for postural hand tremor.

Evaluation of Hand Tremor Frequency Among Patients in Sri Lanka using a Soft Glove

2020 ◽  
Author(s):  
Pasindu Kavindya ◽  
W. V. I. Awantha ◽  
Ashan T. Wanasinghe ◽  
Asitha L. Kulasekera ◽  
Damith Suresh Chathuranga ◽  
...  
Keyword(s):  
Sri Lanka ◽  
Hand Tremor ◽  
Tremor Frequency

scholarly journals Hand-Tremor Frequency Estimation in Videos

2019 ◽  
pp. 213-228 ◽  
Author(s):  
Silvia L. Pintea ◽  
Jian Zheng ◽  
Xilin Li ◽  
Paulina J. M. Bank ◽  
Jacobus J. van Hilten ◽  
...  
Keyword(s):  
Frequency Estimation ◽  
Hand Tremor ◽  
Tremor Frequency

Frequency and displacement amplitude relations for normal hand tremor

1976 ◽  
Vol 40 (1) ◽  
pp. 44-54 ◽  
Author(s):  
R. N. Stiles
Keyword(s):  
Spectral Analysis ◽  
Small Amplitude ◽  
Continuous Extension ◽  
Normal Subjects ◽  
Displacement Amplitude ◽  
Modulation Amplitude ◽  
Mean Square ◽  
Hand Tremor ◽  
Normal Hand ◽  
Tremor Frequency

Spectral analysis of hand tremor records obtained from normal subjects during continuous extension of the hand for 15–45 min revealed that the root-mean-square (rms) displacement amplitude of the tremor increased from control levels of about 30 mum to levels on the order of 100–1,000 times control. Associated with this increase in the displacement was a systematic decrease in the hand tremor frequency from control values of 8–9 Hz to values of 4–6 Hz. Spectral analysis of demodulated extensor EMG records indicated a consistent relation between EMG modulation amplitude at the tremor frequency and the tremor displacement amplitude for tremor records with rms displacement above about 100 mum. No consistent relation was found between these two variables for tremor records with displacements below 100 mum. Consideration of both mechanical and neural reflex effects indicated that a viscoelastic-mass mechanism primarily determined the small-amplitude (less than 100 mum) tremors, while the large displacement tremors may have involved both mechanical and neural feed back factors.

All-Contactless Measurement of Series Resistance Distributions on Solar Cells with Photoluminescence Imaging

2011 ◽  
Author(s):  
M. Kasemann ◽  
L.M. Reindl ◽  
B. Michl ◽  
W. Warta ◽  
A. Schütt ◽  
...  
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Current Flow ◽  
Series Resistance ◽  
Electrical Contacts ◽  
New Method ◽  
Contactless Measurement ◽  
Sample Handling ◽  
Imaging Methods ◽  
Lateral Current

Abstract Conventional series resistance imaging methods require electrical contacts for current injection or extraction in order to generate lateral current flow in the solar cell. This paper presents a new method to generate lateral current flow in the solar cell without any electrical contacts. This reduces the sample handling complexity for inline application and allows for measurements on unfinished solar cell precursors.

APPLICATION OF ACOUSTIC METHODS IN RESEARCHES OF THE BOTTOM SEDIMENT DYNAMICS

2018 ◽  
Author(s):  
Б. Дивинский ◽  
B. Divinskiy ◽  
И. Грюне ◽  
I. Gryune ◽  
Р. Косьян ◽  
...  
Keyword(s):  
Suspended Sediment ◽  
Sediment Concentration ◽  
Irregular Waves ◽  
Single Frequency ◽  
Contactless Measurement ◽  
Measurement Means ◽  
Uniform Field ◽  
Wave Flume ◽  
Acoustic Methods ◽  
Back Scattering

Acoustic methods belong to contactless measurement means, possess high spatial and time resolution. Thus, the use of multifrequency allows directly profile both concentration and granulometric structure of the suspended substances. In 2008 in the Big Wave Flume (Hanover, Germany) by efforts of the Russian and German scientists there have been carried out the experiment on studying the bottom material suspension laws under the influence of irregular waves. The Aquascat 1000 acoustic back scattering sensor (ABS) manufactured by British company Aquatec (www.aquatecsubsea.com), equipped by a three-frequency transmitter with frequencies 1,0, 2,0 and 3,84 MHz, has been set on distance of 0,75 m from the bottom and 111 m from wave generator at the total depth of 3,2 m. Several dozen series of measurements at various parameters of surface waves have been carried out. The general picture of suspension is so that the external dynamic influence (currents, wave movements, turbulence, gravitation forces) creates a non-uniform field (gradient) of the suspended particles and in most cases due to this the average size of particles undergoes to the spatial-time variations. For this reason while defining the mass concentration of suspended sediment, using the single frequency transmitter there is necessity for numerous definition of the suspension granulometric structure what by isn’t always possible. If two and more frequencies are used the observed results comparison can give the information on average diameters of particles and on that basis the calculation of suspended sediment concentration is possibleLet's emphasize the basic advantages of back scattering acoustic gauges usage: – Obtaining the particles sizes and concentration distribution profiles is possible; – The initial granulometric structure of bottom sediments can be unknown (at use of several frequencies). The following can be referred to some lacks of the device: – The system should be calibrated in laboratory conditions; – In a positive feedback conditions the iterative computing process can converge to zero or to infinity. In this case experiments with a variation of carrier frequencies chosen for the analysis allow partially solve the problem (say experiments with different frequencies pairs, as 2/1 of MHz or 4/2 MHz).

scholarly journals A mobile app for tracking non-motor symptoms of people with Parkinson’s disease: A usability study

2020 ◽  
Vol 4 (Supplement_1) ◽  
pp. 890-890
Author(s):  
JuHee Lee ◽  
Yujin Suh ◽  
Yielin Kim
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Tracking System ◽  
Smart Phone ◽  
Telephone Counseling ◽  
Mobile App ◽  
Motor Symptoms ◽  
Hand Tremor ◽  
Non Motor Symptoms

Abstract Smart phone-based technology for people with Parkinson’s disease has been developed worldwide. Unmonitored non-motor symptoms decrease quality of life of people with Parkinson’s disease, so the needs for technology to manage non-motor symptoms are increasing. The technology is needed to detect subtle changes in non-motor symptoms by healthcare professional. There is no mobile app which manage comprehensive symptoms of Parkinson’s disease including non-motor symptoms. It is necessary to develop a new tracking system that can effectively manage non-motor symptoms as well as motor symptoms of Parkinson’s disease. We developed a prototype of mobile app for Android smartphones, with cooperation with Mazelone company. we also have shaped functions for monitoring of motor symptoms and medication adherence. It also provided a section for caregivers to use on behalf of people with Parkinson’s disease who have difficulty to use app due to hand tremor. Through Delphi technique, we obtained content validity from eight medical and nursing experts on the contents of the application. We provided regular telephone counseling to improve and encourage their app usage. Fifteen participants used the app for 6 weeks. To evaluate usability of mobile app, we provided constructed questionnaire and conducted individual telephone interview. A mobile app for tracking non-motor symptoms demonstrated high usability and satisfaction. We learned lessons about facilitators and barriers when implementing an app such as perception and acceptance of mobile technology. The mobile app will improve continuum of care. Future studies need to improve the contents and refine technical approach for people with Parkinson’s disease.

scholarly journals Contactless analysis of heart rate variability during cold pressor test using radar interferometry and bidirectional LSTM networks

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kilin Shi ◽  
Tobias Steigleder ◽  
Sven Schellenberger ◽  
Fabian Michler ◽  
Anke Malessa ◽  
...  
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Dynamic Change ◽  
Cold Pressor Test ◽  
Cold Pressor ◽  
Contactless Measurement ◽  
Pressor Test ◽  
Skin Contact ◽  
Bidirectional Lstm ◽  
Lstm Network

AbstractContactless measurement of heart rate variability (HRV), which reflects changes of the autonomic nervous system (ANS) and provides crucial information on the health status of a person, would provide great benefits for both patients and doctors during prevention and aftercare. However, gold standard devices to record the HRV, such as the electrocardiograph, have the common disadvantage that they need permanent skin contact with the patient. Being connected to a monitoring device by cable reduces the mobility, comfort, and compliance by patients. Here, we present a contactless approach using a 24 GHz Six-Port-based radar system and an LSTM network for radar heart sound segmentation. The best scores are obtained using a two-layer bidirectional LSTM architecture. To verify the performance of the proposed system not only in a static measurement scenario but also during a dynamic change of HRV parameters, a stimulation of the ANS through a cold pressor test is integrated in the study design. A total of 638 minutes of data is gathered from 25 test subjects and is analysed extensively. High F-scores of over 95% are achieved for heartbeat detection. HRV indices such as HF norm are extracted with relative errors around 5%. Our proposed approach is capable to perform contactless and convenient HRV monitoring and is therefore suitable for long-term recordings in clinical environments and home-care scenarios.

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