A novel steady-state visually evoked potential-based brain–computer interface design: Character Plotter

İşcan, Zafer; Dokur, Zümray

doi:10.1016/j.bspc.2013.11.009

Cited by 19 publications

(12 citation statements)

References 22 publications

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“…Canonical correlation analysis (CCA) was used to generate features for classification. For the detailed implementation of the method see [ 18 ]. Briefly, we generated data composed of sine and cosine functions that have the same lengths as the segmented EEG data.…”

Section: Methodsmentioning

confidence: 99%

Steady state visual evoked potential (SSVEP) based brain-computer interface (BCI) performance under different perturbations

İşcan

Nikulin

2018

PLoS ONE

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Brain-computer interface (BCI) paradigms are usually tested when environmental and biological artifacts are intentionally avoided. In this study, we deliberately introduced different perturbations in order to test the robustness of a steady state visual evoked potential (SSVEP) based BCI. Specifically we investigated to what extent a drop in performance is related to the degraded quality of EEG signals or rather due to increased cognitive load. In the online tasks, subjects focused on one of the four circles and gave feedback on the correctness of the classification under four conditions randomized across subjects: Control (no perturbation), Speaking (counting loudly and repeatedly from one to ten), Thinking (mentally counting repeatedly from one to ten), and Listening (listening to verbal counting from one to ten). Decision tree, Naïve Bayes and K-Nearest Neighbor classifiers were used to evaluate the classification performance using features generated by canonical correlation analysis. During the online condition, Speaking and Thinking decreased moderately the mean classification accuracy compared to Control condition whereas there was no significant difference between Listening and Control conditions across subjects. The performances were sensitive to the classification method and to the perturbation conditions. We have not observed significant artifacts in EEG during perturbations in the frequency range of interest except in theta band. Therefore we concluded that the drop in the performance is likely to have a cognitive origin. During the Listening condition relative alpha power in a broad area including central and temporal regions primarily over the left hemisphere correlated negatively with the performance thus most likely indicating active suppression of the distracting presentation of the playback. This is the first study that systematically evaluates the effects of natural artifacts (i.e. mental, verbal and audio perturbations) on SSVEP-based BCIs. The results can be used to improve individual classification performance taking into account effects of perturbations.

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Section: Methodsmentioning

confidence: 99%

Steady state visual evoked potential (SSVEP) based brain-computer interface (BCI) performance under different perturbations

İşcan

Nikulin

2018

PLoS ONE

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“…Biopotential monitoring of the brain activity (electroencephalography, EEG) is of paramount importance to modern medicine, in order to investigate a wide range of physiological and pathological brain functions or even for brain computer interfaces (BCI) research [1,2]. The Ag/AgCl electrodes [3][4][5] are considered the most appropriate for signal acquisition, exhibiting an essentially non-polarizable, resistive behaviour, also displaying an excellent reliability and low, almost frequency-independent skin-contact impedance values, in the order of few tens of kV cm 2 [4,5].…”

Section: Introductionmentioning

confidence: 99%

Electrochemical and structural characterization of nanocomposite Agy:TiNx thin films for dry bioelectrodes: the effect of the N/Ti ratio and Ag content

Pedrosa

Machado

Fiedler

et al. 2015

Electrochimica Acta

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“…The conventional wet silver/silver chloride (Ag/AgCl) electrodes are considered the most suitable for biosignal acquisition and are widely used in routine clinical practices and medical research, such as multichannel electroencephalography (EEG), or even brain–computer interfaces . They exhibit an essentially non‐polarizable, resistive behavior, also displaying an excellent reliability and low, almost frequency‐independent skin‐contact impedance values, in the order of few tens of kΩ · cm 2 .…”

Section: Introductionmentioning

confidence: 99%

“…The conventional wet silver/silver chloride (Ag/AgCl) electrodes are considered the most suitable for biosignal acquisition [1][2][3] and are widely used in routine clinical practices and medical research, such as multichannel electroencephalography (EEG), [4,5] or even brain-computer interfaces. [6][7][8] They exhibit an essentially non-polarizable, resistive behavior, also displaying an excellent reliability and low, almost frequency-independent skin-contact impedance values, in the order of few tens of kV Á cm 2 . [2,3] However, the wet Ag/AgCl electrodes suffer from intrinsic technological drawbacks, including difficult, time-consuming, and error-prone skin preparation, [1] as well as limited long-term stability of the gel electrolytes and constant risk of hair damage and skin irritation.…”

Section: Introductionmentioning

confidence: 99%

Ag:TiN‐Coated Polyurethane for Dry Biopotential Electrodes: From Polymer Plasma Interface Activation to the First EEG Measurements

Pedrosa

Fiedler

Lopes

et al. 2015

Plasma Processes & Polymers

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Several plasma treatments using argon, oxygen, and nitrogen are studied in order to increase the interfacial adhesion of the polyurethane/Ag:TiN system to be used as biopotential electrodes. The optimized plasma treatments conditions (100 W, 15 min, regardless of the gas) promote a steep decrease of the water contact angle values. The observed chemical and topographic alterations translate into excellent polyurethane/Ag:TiN interfacial adhesion of the plasma treated samples. The in-service validation of the proposed Ag:TiN-coated PU multipin electrodes is performed by acquiring EEG signals in parallel with the standard wet Ag/AgCl electrodes. No considerable differences are found in terms of shape, amplitude, and spectral characteristics of the signals when comparing reference wet and dry electrodes.

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A novel steady-state visually evoked potential-based brain–computer interface design: Character Plotter

Cited by 19 publications

References 22 publications

Steady state visual evoked potential (SSVEP) based brain-computer interface (BCI) performance under different perturbations

Steady state visual evoked potential (SSVEP) based brain-computer interface (BCI) performance under different perturbations

Electrochemical and structural characterization of nanocomposite Agy:TiNx thin films for dry bioelectrodes: the effect of the N/Ti ratio and Ag content

Ag:TiN‐Coated Polyurethane for Dry Biopotential Electrodes: From Polymer Plasma Interface Activation to the First EEG Measurements

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