Wyniki wyszukiwania - Biblioteka Nauki

1

APW program - extension of the Neuroscan system for extraction and Analysis of Cortical Evoked Potentials

100%

Kowalczyk L. , Zalewska E.

Biocybernetics and Biomedical Engineering

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2005

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tom Vol. 25, no. 2

61-67

EN

The Scan 4.2 program from the Neuroscan package is designed for the analysis of EEG signals and cortical evoked potentials. The signals are recorded on-line during the subject stimulation. This enables us to examine the dependency of the evoked potentials on changes in the spontaneous activity. Such an analysis requires selection of events, according to the given criteria, and then extraction of the deterministic and random component in the recorded signal after the event. The purpose of the application presented is to extend the Neuroscan package with such a function. The APW program (the Analyzer of Evoked Potentials) is able to select data for the analysis and extract the random component of the EEG signal. The program uses data files of the Neuroscan binary format and calculates a series, whose elements are segments of the recorded signals of a given time before and after the event. The results of the APW analysis can also be read and visualized using the Scan application from the Neuroscan. To test the analysis, a simple test data generator is included. Other unique features of APW are different types of the similarity analysis of the EEG signals.

2

Multilayer boundary element method for source localization in electroencephalography

100%

Filipowicz S. F. , Nita K. , Sikora J.

Poznan University of Technology Academic Journals. Electrical Engineering

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2006

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tom No 52

63-72

EN

Boundary Element Method for simulation of spatially homogeneous objects of electroencephalography and tomography is presented in this paper. The four layer spherical model (representing skin, skull, CSF layer and brain) of the real head approximated with isoparametric six nodes triangles was considered. For different kinds of boundary conditions formulation of the algebraic system of equations was explained in details.

3

Cooperation of CUDA and Intel multi-core architecture in the independent component analysis algorithm for EEG data

100%

Gajos-Balińska A. , Wójcik G. M. , Stpiczyński P.

Bio-Algorithms and Med-Systems

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2020

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tom Vol. 16, no. 3

art. no. 20200044

EN

Objectives: The electroencephalographic signal is largely exposed to external disturbances. Therefore, an important element of its processing is its thorough cleaning. Methods: One of the common methods of signal improvement is the independent component analysis (ICA). However, it is a computationally expensive algorithm, hence methods are needed to decrease its execution time. One of the ICA algorithms (fastICA) and parallel computing on the CPU and GPU was used to reduce the algorithm execution time. Results: This paper presents the results of study on the implementation of fastICA, which uses some multi-core architecture and the GPU computation capabilities. Conclusions: The use of such a hybrid approach shortens the execution time of the algorithm.

4

Using LORETA Method Based on the EEG Signal for Localizing the Sources of Brain Waves Activity

100%

Paszkiel S.

Measurement Automation Monitoring

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2016

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tom Vol. 62, No. 8

262--264

EN

The article presents the possibility of using the method of imaging brain activity, LORETA LOw Resolution Electromagnetic TomogrAphy), that can base on electroencephalographical and magnetoencephalographical readings. Thanks to using the above-mentioned method, it is possible to localize the sources of the activity of individual signals registered on the head surface. This is very significant regarding construction of the brain-computer interfaces in order to conduct proper identification and classification of signals obtained during electroencephalography.

5

Initial study on changes in activity of brain waves during audio stimulation using noninvasive brain-computer interfaces: choosing the appropriate filtering method

88%

Browarska N. , Kawala-Sterniuk A. , Zygarlicki J.

Bio-Algorithms and Med-Systems

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2021

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tom Vol. 17, no. 2

79--93

EN

Objectives: In this paper series of experiments were carried out in order to check the influence of various sounds on human concentration during visually stimulated tasks performance. Methods: The obtained data was filtered. For the study purposes various smoothing filters were tested, including Median and Savitzky-Golay Filters; however, median filter only was applied. Implementation of this filter made the obtained data more legible and useful for potential diagnostics purposes. The tests were carried out with the implementation of the Emotiv Flex EEG headset. Results: The obtained results were promising and complied with the initial assumptions, which stated that the “relax”- phase, despite relaxing sounds stimuli, is strongly affected with the “focus”-phase with distracting sounds, which is clearly visible in the shape of the recorded EEG data. Conclusions: Further investigations with broader range of subjects is being currently carried out in order to confirm the already obtained results.

6

An empirical survey of electroencephalographybased brain-computer interfaces

88%

Wankhade M. M. , Chorage S. S.

Bio-Algorithms and Med-Systems

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2020

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tom Vol. 16, no. 4

art. no. 20190053

EN

Objectives: The Electroencephalogram (EEG) signal is modified using the Motor Imagery (MI) and it is utilized for patients with high motor impairments. Hence, the direct relationship between the computer and brain is termed as an EEG-based brain-computer interface (BCI). The objective of this survey is to presents an analysis of the existing distinct BCIs based on EEG. Methods: This survey provides a detailed review of more than 60 research papers presenting the BCI-based EEG, like motor imagery-based techniques, spatial filtering-based techniques, Steady-State Visual Evoked Potential (SSVEP)- based techniques, machine learning-based techniques, Event-Related Potential (ERP)-based techniques, and online EEG-based techniques. Subsequently, the research gaps and issues of several EEG-based BCI systems are adopted to help the researchers for better future scope. Results: An elaborative analyses as well as discussion have been provided by concerning the parameters, like evaluation metrics, year of publication, accuracy, implementation tool, and utilized datasets obtained by various techniques. Conclusions: This survey paper exposes research topics on BCI-based EEG, which helps the researchers and scholars, who are interested in this domain.

7

Evaluation of Emotiv EEG neuroheadset

88%

Wójcik G. M. , Wierzgała P. , Gajos A.

Bio-Algorithms and Med-Systems

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2015

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tom Vol. 11, no. 4

211--215

EN

Electroencephalography (EEG) has become more popular, and as a result, the market grows with new EEG products. The new EEG solutions offer higher mobility, easier application, and lower price. One of such devices that recently became popular is Emotiv EEG. It has been already tested in various applications concerning brain-computer interfaces, neuromarketing, language processing, and detection of the P-300 component, with a general result that it is capable of recording satisfying research data. However, no one has tested and described its usefulness in long-term research. This article presents experience from using Emotiv EEG in two research projects that involved 39 subjects for 22 sessions. Emotiv EEG has significant technical issues concerning the quality of its screw threads. Two complete and successful solutions to this problem are described.

8

The importance of electroencephalography in the diagnosis of hepatic encephalopathy due to cirrhosis – a case report

88%

Fuksa K.

European Journal of Clinical and Experimental Medicine

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2022

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nr 2

224-231

EN

Introduction and aim. Hepatic encephalopathy (HE) associated with cirrhosis of the liver is a neuropsychiatric syndrome, with symptoms ranging from barely detectable changes to deep coma. It frequently occurs in the form of episodes and relapses and can be triggered by external factors. HE severity is graded according to the West Haven criteria. The aim of the study is to draw attention to the ever-important and often key role of electroencephalography in the diagnosis of hepatic encephalopathy, even in today’s era of increasingly advanced diagnostic methods. Description of the case. A 57-year-old patient, professionally active at the time, was admitted to the hospital’s Neurology Department on an emergency basis due to difficulties with standing and moving, orientation disorders and limb tremor. Conclusion. While HE pathogenesis is multifactorial, the most important factors include increased brain exposure to ammonia, intestinal dysbiosis, and endotoxemia inducing a systemic inflammatory response. Patient observation, blood laboratory tests, neuropsychological tests and neurophysiological tests (EEG and evoked potentials) play an important role in establishing the diagnosis. Treatment and secondary prevention of hepatic encephalopathy include elimination of triggers and reduction of ammonia production and improvement of its metabolism.

9

Analysis of brain waves changes in stressful situations based on horror game with the implementation of virtual reality and braincomputer interface system: a case study

88%

Browarska N. , Kawala-Sterniuk A. , Chechelski P. , Zygarlicki J.

Bio-Algorithms and Med-Systems

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2020

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tom Vol. 16, no. 4

art. no. 20200050

EN

Objectives: This presents a case for fear and stress stimuli and afterward EEG data analysis. Methods: The stress factor had been evoked by a computer horror game correlated with virtual reality (VR) and brain-computer interface (BCI) from OpenBCI, applied for the purpose of brain waves changes observation. Results: Results obtained during the initial study were promising and provide conclusions for further research in this field carried out on an expanded group of involved participants. Conclusions: The study provided very promising and interesting results. Further investigation with larger amount of participants will be carried out.

10

Development of Visual Evoked Potentials Detection AIgorithm for objective perimetry

75%

Drozd M. , Nowakowski A.

Biocybernetics and Biomedical Engineering

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2005

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tom Vol. 25, no. 3

47-55

EN

Objective perimetry, based on the EEG signal analysis, represents a new trend in evaluation of the human visual system. At the moment, the work is concentrated on the effective algorithms of the EEG analysis for the weak transient VEP signal detection. A new algorithm for a rapid detection of visual cortical signals - the VEPDA - was developed. For evaluation of the algorithm, two approaches are considered. The first one, based on synthetic cortical potentials and artificial, spontaneous EEG, with all data generated in the developed model, and the second one, using the real EEG data taken from measurements and mixed with the synthetic VEP signal. The approach presented in this paper concerns application of VEPDA to the modelled VEP embedded in the real, ongoing EEG signal. The final step of the work is practical implementation of the method. The research results prove the validity of the algorithm applied to the modelled data. Here, the value of VEPDA usefulness in the analysis of the real EEG recording has been verified.

11

Analysis of the application of brain-computer interfaces of a selected paradigm in everyday life

75%

Mróz K. , Plechawska-Wójcik M.

Journal of Computer Sciences Institute

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2022

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tom Vol. 23

118--122

EN

The main objective of this paper is to carry out a research on the analysis of the use of brain-computer interface in everyday life. The article presents the method of recording brain activity, electroencephalography, which was used in the study. The brain activity used in the brain-computer interface and the general principle of brain-computer interface design are also described. The performed study allowed to develop an analysis of the obtained results in the matter of evaluating the usability of brain-computer interfaces using motor imagery. As a result of the process of analyzing the results obtained during the research, it was found that each subsequent experiment allowed for obtaining more favourable results than the previous one. The reason for this was the use of an additional training session for the next test person. In the final stage, it was possible to evaluate the usability of the brain-computer interface in everyday life

PL

Głównym celem artykułu jest przeprowadzenie badania nad analizą wykorzystania interfejsu mózg-komputer w życiu codziennym. W artykule przedstawiono metodę rejestrowania aktywności mózgu, elektroencefalografię, która została wykorzystana w badaniu. Opisano również aktywność mózgu wykorzystywaną w interfejsie mózg-komputer oraz ogólną zasadę projektowania interfejsu mózg-komputer. Przeprowadzone badanie pozwoliło na opracowanie analizy uzyskanych wyników w zakresie oceny użyteczności interfejsów mózg-komputer z wykorzystaniem obrazowania motorycznego. W wyniku procesu analizy wyników uzyskanych podczas przeprowadzania badań ustalono, iż każdy następnie zrealizowany eksperyment pozwalał na uzyskanie korzystniejszych wyników od poprzedniego. Powodem tego było zastosowanie dodatkowej sesji treningowej dla kolejnych badanych osób. W końcowym etapie można było ocenić przydatność interfejsu mózg-komputer w życiu codziennym

12

Time-frequency-space localization of epileptic EEG oscillations

75%

Matysiak A. , Durka P. J. , Montes E. M. , Barwinski M. , Zwolinski P. , Roszkowski M. , Blinowska K. J.

Acta Neurobiologiae Experimentalis

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2005

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tom 65

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nr 4

13

Diagnostyka niejednorodnych obiektów przestrzennych metodami tomografii impendacyjnej i elektroencefalografii

75%

Filipowicz S. F.

Prace Naukowe Politechniki Warszawskiej. Elektryka

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2005

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tom z. 132

3--122

PL

Celem niniejszej pracy jest przedstawienie metod badawczych, konstrukcji aparatury i algorytmów stosowanych przy rozwiązywaniu zagadnień związanych z diagnostyką niejednorodnych obiektów przestrzennych metodami tomografii impedancyjnej (TI) i elektroencefalografii (EEG). Metody te zalicza się do szeroko rozumianych badań nieniszczących. W pracy zostały przedstawione systemy pomiarowe skonstruowane przez autora i stosowane w pracach badawczych i aplikacyjnych. W szczególności omówiono problemy, które można spotkać przy tworzeniu algorytmów numerycznych wykorzystywanych do konstrukcji obrazu. Niektóre zagadnienia związane z algorytmami konstrukcji obrazu, jak metoda elementów brzegowych, są zaprezentowane szerzej w celu uogólnienia przedstawianej tematyki. Przedstawiono wyniki prac dotyczące konstrukcji obrazu wnętrza badanego obiektu na podstawie pomiarów i danych symulacyjnych. Pracę można podzielić na pięć części. Część pierwsza zawiera sformułowanie problemu, stan badań w TI i EEG oraz cel i zakres pracy (rozdział l). W części drugiej przedstawiono model matematyczny zadania, metody rozwiązań, zastosowanie metody elementów skończonych (MES) i metody elementów brzegowych (MEB) w TI i EEG, analizę wrażliwościową, sformułowanie zagadnienia prostego, wyniki rozwiązania zagadnienia odwrotnego, porównanie rozwiązań na podstawie przykładów. Omówione problemy stanowią treść rozdziału 2. Część trzecia zawiera założenia, możliwości rozwiązań systemów i układów pomiarowych wykorzystywanych w TI i EEG, metody klasyfikacji i redukcji sygnałów, ocenę właściwości metrologicznych oraz realizacji kolejnych rozwiązań. Przedstawiono podstawowe informacje o układach pomiarowych oraz kolejne fazy rozwoju tomografu impedancyjnego w Instytucie Elektrotechniki Teoretycznej i Systemów Informacyjno-Pomiarowych Politechniki Warszawskiej. Problemy te opisano w rozdziałach 3 i 4. Część czwarta (rozdziały 5 i 6) dotyczy konstrukcji obrazu w TI, algorytmów konstrukcji, porównania właściwości, identyfikacji źródeł wewnętrznych w EEG, separacji sygnałów i przykładów rozwiązań na podstawie danych symulacyjnych i uzyskanych z fantomów. Rozdział 7, stanowiący część piątą, jest podsumowaniem pracy, zawierającym syntetyczne streszczenie osiągniętych wyników, najważniejsze wnioski i wkład autora w przedstawianą tematykę oraz przyszłe kierunki prac związanych z tą tematyką badawczą.

EN

The main goal of this work is to present research methods, designs for Electrical Impedance Tomography apparatus and numerical algorithms which are applied for the solution of the problems concerned with the diagnosis of non-homogeneous objects in 2D and 3D space. The author concentrated chiefly on Impedance Tomography (EIT) and Electroencephalography (EEG). Those two methods are broad class methods of non-destructive testing of materials. The measuring systems constructed by the author and used in the research tasks are presented in this work. Special attention was paid to the problems one can have constructing algorithms for image building. Some aspects of image construction (like the Boundary Element Method (BEM)) are presented in greater detail. Results of the research based on synthetic and measured data are included. This work consists of five parts. The first part consists of problem formulation, the state of the art in EIT and EEG, the goal and the scope of this monograph. In the second part, a mathematical models, forward problem solution methods adopting the Finite Element Method (FEM) or the Boundary Element Method (BEM), Sensitivity Analysis (SA) and finally Inverse Problem solution are presented. Different methods of solution were compared based on the benchmarks proposed by the author. This part can be found in chapter 2 and chapter 3.Part three discuss the assumptions imposed and limitations of the solutions as well as basic information about the measuring systems in EIT and EEG. The history of designing the Electrical Impedance Tomograph in the Institute of Theory of Electrical Engineering, Measurement and Information Systems of Warsaw University of Technology is also described. Special attention was devoted to signal dimensionality reduction and some illustrating examples were shown. These problems are contained in chapters four and chapter five. Part four consist of chapters six seven and eight concerned with image construction methods in EIT and also the methods of identification (or maybe more precisely localization) of internal sources in EEG. The author proposes an innovative method of identification relay on blind separation of measured signals in the case of more than one internal source. The last part, chapter nine concludes this work. There is a concise abstract of the whole research carried out by the author in the subject of EIT and EEG, the most important conclusions, the author is achievements and the future research relating to the above research subjects.

14

EEG afterdischarge patterns and performance of the avoidance response in hippocampally kindled cats

75%

Majkowski J. , Sobieszek A. , Dlawichowska E.

Acta Neurobiologiae Experimentalis

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1989

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tom 49

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nr 1

15

Rola elektroencefalografii w diagnostyce i monitorowaniu przebiegu ostrego zapalenia mózgu u dzieci. Opis przypadków

75%

Kemnitz P. , Frąszczak J. , Mazur-Melewska K. , Mania A. , Jończyk-Potoczna K. , Figlerowicz M.

Neurologia Dziecięca

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2021-2022

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tom 31-32

|

nr 60

61-67

EN

Neuroelectrophysiological tests enable a non-invasive assessment of the nervous system function, thus playing an important role in the diagnostic process of neurological diseases. Electroencephalography is the most commonly used test in this group and primarily applied in the diagnosis of paroxysmal diseases. The undoubted advantages of the method are its repeatability and the possibility of comparison over time, which, combined with non-invasiveness, extends its application to monitoring the course of the disease. In this paper we present descriptions of three patients with diagnosis of encephalitis treated in our Department, for whom the use of electroencephalography was important in confirming the initial diagnosis and enabled the early initiation of adequate, intensive treatment.

PL

Badania neuroelektrofizjologiczne umożliwiają nieinwazyjną ocenę czynności układu nerwowego, pełniąc tym samym istotną rolę w procesie diagnostycznym schorzeń neurologicznych. Elektroencefalografia jest najpowszechniej wykorzystywanym badaniem z tej grupy, mającym przede wszystkim zastosowanie w rozpoznawaniu chorób o charakterze napadowym. Niewątpliwymi zaletami metody są powtarzalność i możliwość porównywania w czasie, co w połączeniu z bezinwazyjnością rozszerza jej zastosowanie o monitorowanie przebiegu choroby. W pracy przedstawiamy opisy trojga pacjentów leczonych w Klinice z powodu zapalenia mózgu, u których wykorzystanie elektroencefalografii miało istotne znaczenie w potwierdzeniu wstępnego rozpoznania i umożliwiło włączenie adekwatnego, intensywnego leczenia.

16

Analiza porównawcza reakcji na bodźce wzrokowe i słuchowe w badaniach potencjałów wywołanych EEG

75%

Tyburcy Ł. , Plechawska-Wójcik M.

Journal of Computer Sciences Institute

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2018

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tom Vol. 7

172--177

PL

Artykuł opisuje badania polegające na porównaniu czasów reakcji na bodźce wzrokowe i słuchowe przy pomocy potencjałów wywołanych EEG. Do realizacji badań wykorzystano dwa eksperymenty. Pierwszy badał czasy reakcji na bodźce wzrokowe, drugi badał czasy reakcji na bodźce słuchowe. Po przeprowadzeniu analizy danych uzyskane rezultaty pozwoliły określić, że bodźce wzrokowe wywołują szybszą reakcję niż bodźce słuchowe.

EN

The paper describes results of comparison of reactions times to visual and auditory stimuli using EEG evoked potentials. Two experiments were used to applied. The first one explored reaction times to visual stimulus and the second one to auditory stimulus. After conducting an analysis of data, received results enable determining that visual stimuli evoke faster reactions than auditory stimuli.

17

Entry level EEG amplifier dedicated for P300 evoked potentials measurements

75%

Bartnik J. , Rak R.

Przegląd Elektrotechniczny

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2010

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tom R. 86, nr 1

178-179

EN

Project of an entry level EEG amplifier dedicated for P300 evoked potentials measurements will be discussed. Amplifier main application is wireless communication between brain and a PC (BCI) which would allow locked-state people to communicate. The device should be mobile, energy efficient and inexpensive.

PL

W artykule przedstawiono projekt ekonomicznego wzmacniacza EEG z przeznaczeniem do pomiaru potencjałów wywołanych - P300. Głównym zastosowaniem wzmacniacza jest bezprzewodowa komunikacja mózg-komputer, która umożliwiłaby osobom całkowicie sparaliżowanym na porozumiewanie się. Urządzenie powinno być mobilne, energooszczędne i tanie.

18

Genetic algorithm and forward method for feature selection in EEG feature space

75%

Rejer I. , Lorenz K.

Journal of Theoretical and Applied Computer Science

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2013

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tom Vol. 7, nr 2

72--82

EN

There are a lot of problems that arise in the process of building a brain-computer interface based on electroencephalographic signals (EEG). A huge imbalance between a number of experiments possible to conduct and the size of feature space, containing features extracted from recorded signals, is one of them. To reduce this imbalance, it is necessary to apply methods for feature selection. One of the approaches for feature selection, often taken in brain-computer interface researches, is a classic genetic algorithm that codes all features within each individual. In this study, there will be shown, that although this approach allows obtaining a set of features of high classification precision, it also leads to a feature set highly redundant comparing to a set of features selected using a forward selection method or a genetic algorithm equipped with individuals of a given (very small) number of genes.

19

Experimental Study of Clothing Tactile Comfort Based on Electro-neurophysiology

75%

Wang Y. , Wang Y. , Zhao M. M. , Yu M. , Li J.

Fibres & Textiles in Eastern Europe

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2014

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tom Vol. 22, no. 4 (106)

102--106

EN

Electromyography (EMG) and electroencephalography (EEG) methods were used to evaluate the reaction of human skin to tactile stimuli evoked by textiles. The peak value of the EMG and energy percentage of the weave of the EEG when the subjects came into contact with 9 kinds of fabrics were selected for tests and next clothing was made on their basis. They were utilized as two important evaluating indexes. Statistical analysis was carried out to verify the correlation between the data obtained from objective measurements and the subjective measurements. The results showed that when the subjects came into contact with thicker, heavier and stiffer fabrics, the peak values of the myoelectric potential induced were higher. When clothing with a higher mass density was worn, energy percentages of the weave at both the left and right occipitalia were higher.

PL

Dla oceny reakcji ludzkiej skóry na dotykowe stymulacje materiałami włóknistymi stosowano elektromiografię (EMG) i elektroencefalografie (EEG). Wartość szczytowa przebiegu EMG oraz procent energii fali EEG w czasie kiedy badane osoby znajdowały się w kontakcie z 9 rodzajami materiałów włókienniczych posłużyła do ich selekcji dla stosowanych testów. Na tej podstawie wykonano odzież przeznaczona dla osób testowanych. Przeprowadzono analizę statystyczna dla zweryfikowania korelacji pomiędzy wynikami uzyskanymi z obiektywnych pomiarów oraz subiektywnych testów. Wyniki wykazały, że kiedy osoby badane znajdowały się w kontakcie z grubszymi i cięższymi i sztywniejszymi materiałami to wartość piku EMG była wyższa. Kiedy ubranie wykonane było z udziałem przędz o wyższej masie liniowej procent energii fali lewej i prawej połówki potylicy był wyższy.

20

Intra-individual reaction time variability and response preparation: an EEG study

75%

Dankinas D. , Parciauskaite V. , Dapsys K.

Acta Neurobiologiae Experimentalis

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2015

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tom 75

|

nr 4

EN

To behave more efficiently the human brain must anticipate future events with different probabilities and prepare appropriate responses. Previous studies demonstrated that participants react faster to more probable stimuli. It has been shown that this effect in reaction time reduction is related to the response preparation process. However it is still unknown what the minimum difference in stimulus probabilities is that is sufficient to elicit response preparation as measured with the EEG. Intra-individual reaction time variability indicates the stability of an individual’s response performance and provides useful information about cognitive functioning. It’s use has become prevalent in recent clinical studies. In order to extend understanding of cognitive and neural mechanisms of response stability we hypothesized that intra-individual reaction time variability relates to the response preparation process. Specifically, we hypothesized that response preparation to more probable stimuli would result in not only faster reaction time but also in a reduction of response variability. To verify this hypothesis, we tested 14 healthy subjects using reaction time and EEG as dependent measures. Two different stimuli with probabilities of 33.3% and 66.6% were assigned to two counterbalanced responses. The results of our study showed that stimulus probabilities of 66.6% and 33.3% were sufficient to elicit response preparation. Our data also revealed that response preparation to more probable stimuli speeds RT and reduces RT variability.