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Spatial and Time Domain Feature of ERP Speller System Extracted via Convolutional Neural Network. COMPUTATIONAL INTELLIGENCE AND NEUROSCIENCE 2018; 2018:6058065. [PMID: 29861712 PMCID: PMC5976923 DOI: 10.1155/2018/6058065] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/06/2018] [Revised: 03/05/2018] [Accepted: 04/01/2018] [Indexed: 11/25/2022]
Abstract
Feature of event-related potential (ERP) has not been completely understood and illiteracy problem remains unsolved. To this end, P300 peak has been used as the feature of ERP in most brain–computer interface applications, but subjects who do not show such peak are common. Recent development of convolutional neural network provides a way to analyze spatial and temporal features of ERP. Here, we train the convolutional neural network with 2 convolutional layers whose feature maps represented spatial and temporal features of event-related potential. We have found that nonilliterate subjects' ERP show high correlation between occipital lobe and parietal lobe, whereas illiterate subjects only show correlation between neural activities from frontal lobe and central lobe. The nonilliterates showed peaks in P300, P500, and P700, whereas illiterates mostly showed peaks in around P700. P700 was strong in both subjects. We found that P700 peak may be the key feature of ERP as it appears in both illiterate and nonilliterate subjects.
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Kellicut-Jones MR, Sellers EW. P300 brain-computer interface: comparing faces to size matched non-face stimuli. BRAIN-COMPUTER INTERFACES 2018. [DOI: 10.1080/2326263x.2018.1433776] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- M. R. Kellicut-Jones
- Department of Psychology, East Tennessee State University, Johnson City, TN, USA
| | - E. W. Sellers
- Department of Psychology, East Tennessee State University, Johnson City, TN, USA
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Piña-Ramirez O, Valdes-Cristerna R, Yanez-Suarez O. Scenario Screen: A Dynamic and Context Dependent P300 Stimulator Screen Aimed at Wheelchair Navigation Control. COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 2018; 2018:7108906. [PMID: 29666663 PMCID: PMC5832133 DOI: 10.1155/2018/7108906] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Revised: 12/21/2017] [Accepted: 01/04/2018] [Indexed: 12/02/2022]
Abstract
P300 spellers have been widely modified to implement nonspelling tasks. In this work, we propose a "scenario" stimulation screen that is a P300 speller variation to command a wheelchair. Our approach utilized a stimulation screen with an image background (scenario snapshot for a wheelchair) and stimulation markers arranged asymmetrically over relevant landmarks, such as suitable paths, doors, windows, and wall signs. Other scenario stimulation screen features were green/blue stimulation marker color scheme, variable Interstimulus Interval, single marker stimulus mode, and optimized stimulus sequence generator. Eighteen able-bodied subjects participated in the experiment; 78% had no experience in BCI usage. A waveform feature analysis and a Mann-Whitney U test performed over the pairs of target and nontarget coherent averages confirmed that 94% of the subjects elicit P300 (p < .005) on this modified stimulator. Least Absolute Shrinkage and Selection Operator optimization and Linear Discriminant Analysis were utilized for the automatic detection of P300. For evaluation with unseen data, target detection was computed (median sensitivity = 1.00 (0.78-1.00)), together with nontarget discrimination (median specificity = 1.00 (0.98-1.00)). The scenario screen adequately elicits P300 and seems suitable for commanding a wheelchair even when users have no previous experience on the BCI spelling task.
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Affiliation(s)
- Omar Piña-Ramirez
- Neuroimaging Research Laboratory, Electrical Engineering Department, Universidad Autonoma Metropolitana Unidad Iztapalapa, Av. San Rafael Atlixco 186, Col. Vicentina, Iztapalapa, 09340 Ciudad de México, Mexico
| | - Raquel Valdes-Cristerna
- Neuroimaging Research Laboratory, Electrical Engineering Department, Universidad Autonoma Metropolitana Unidad Iztapalapa, Av. San Rafael Atlixco 186, Col. Vicentina, Iztapalapa, 09340 Ciudad de México, Mexico
| | - Oscar Yanez-Suarez
- Neuroimaging Research Laboratory, Electrical Engineering Department, Universidad Autonoma Metropolitana Unidad Iztapalapa, Av. San Rafael Atlixco 186, Col. Vicentina, Iztapalapa, 09340 Ciudad de México, Mexico
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Operation of a P300-based brain-computer interface in patients with Duchenne muscular dystrophy. Sci Rep 2018; 8:1753. [PMID: 29379140 PMCID: PMC5788861 DOI: 10.1038/s41598-018-20125-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Accepted: 01/09/2018] [Indexed: 11/18/2022] Open
Abstract
A brain-computer interface (BCI) or brain-machine interface is a technology that enables the control of a computer and other external devices using signals from the brain. This technology has been tested in paralysed patients, such as those with cervical spinal cord injuries or amyotrophic lateral sclerosis, but it has not been tested systematically in Duchenne muscular dystrophy (DMD), which is a severe type of muscular dystrophy due to the loss of dystrophin and is often accompanied by progressive muscle weakness and wasting. Here, we investigated the efficacy of a P300-based BCI for patients with DMD. Eight bedridden patients with DMD and eight age- and gender-matched able-bodied controls were instructed to input hiragana characters. We used a region-based, two-step P300-based BCI with green/blue flicker stimuli. EEG data were recorded, and a linear discriminant analysis distinguished the target from other non-targets. The mean online accuracy of inputted characters (accuracy for the two-step procedure) was 71.6% for patients with DMD and 80.6% for controls, with no significant difference between the patients and controls. The P300-based BCI was operated successfully by individuals with DMD in an advanced stage and these findings suggest that this technology may be beneficial for patients with this disease.
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Okahara Y, Takano K, Komori T, Nagao M, Iwadate Y, Kansaku K. Operation of a P300-based brain-computer interface by patients with spinocerebellar ataxia. Clin Neurophysiol Pract 2017; 2:147-153. [PMID: 30214988 PMCID: PMC6123944 DOI: 10.1016/j.cnp.2017.06.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Revised: 06/12/2017] [Accepted: 06/24/2017] [Indexed: 11/16/2022] Open
Abstract
Objective We investigated the efficacy of a P300-based brain-computer interface (BCI) for patients with spinocerebellar ataxia (SCA), which is often accompanied by cerebellar impairment. Methods Eight patients with SCA and eight age- and gender-matched healthy controls were instructed to input Japanese hiragana characters using the P300-based BCI with green/blue flicker. All patients depended on some assistance in their daily lives (modified Rankin scale: mean 3.5). The chief symptom was cerebellar ataxia; no cognitive deterioration was present. A region-based, two-step P300-based BCI was used. During the P300 task, eight-channel EEG data were recorded, and a linear discriminant analysis distinguished the target from other nontarget regions of the matrix. Results The mean online accuracy in BCI operation was 82.9% for patients with SCA and 83.2% for controls; no significant difference was detected. Conclusion The P300-based BCI was operated successfully not only by healthy controls but also by individuals with SCA. Significance These results suggest that the P300-based BCI may be applicable for patients with SCA.
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Affiliation(s)
- Yoji Okahara
- Systems Neuroscience Section, Department of Rehabilitation for Brain Functions, Research Institute of National Rehabilitation for Persons with Disabilities, Tokorozawa, Saitama 359-8555, Japan.,Department of Neurological Surgery, Chiba University Graduate School of Medicine, Chiba, Chiba 260-8670, Japan
| | - Kouji Takano
- Systems Neuroscience Section, Department of Rehabilitation for Brain Functions, Research Institute of National Rehabilitation for Persons with Disabilities, Tokorozawa, Saitama 359-8555, Japan
| | - Tetsuo Komori
- Department of Neurology, National Hakone Hospital, Odawara, Kanagawa 250-0032, Japan
| | - Masahiro Nagao
- Department of Neurology, Tokyo Metropolitan Neurological Hospital, Fuchu, Tokyo 183-0042, Japan
| | - Yasuo Iwadate
- Department of Neurological Surgery, Chiba University Graduate School of Medicine, Chiba, Chiba 260-8670, Japan
| | - Kenji Kansaku
- Systems Neuroscience Section, Department of Rehabilitation for Brain Functions, Research Institute of National Rehabilitation for Persons with Disabilities, Tokorozawa, Saitama 359-8555, Japan.,Brain Science Inspired Life Support Research Center, The University of Electro-Communications, Chofu, Tokyo 182-8585, Japan
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Carabalona R. The Role of the Interplay between Stimulus Type and Timing in Explaining BCI-Illiteracy for Visual P300-Based Brain-Computer Interfaces. Front Neurosci 2017; 11:363. [PMID: 28713233 PMCID: PMC5492449 DOI: 10.3389/fnins.2017.00363] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2016] [Accepted: 06/12/2017] [Indexed: 11/13/2022] Open
Abstract
Visual P300-based Brain-Computer Interface (BCI) spellers enable communication or interaction with the environment by flashing elements in a matrix and exploiting consequent changes in end-user's brain activity. Despite research efforts, performance variability and BCI-illiteracy still are critical issues for real world applications. Moreover, there is a quite unaddressed kind of BCI-illiteracy, which becomes apparent when the same end-user operates BCI-spellers intended for different applications: our aim is to understand why some well performers can become BCI-illiterate depending on speller type. We manipulated stimulus type (factor STIM: either characters or icons), color (factor COLOR: white, green) and timing (factor SPEED: fast, slow). Each BCI session consisted of training (without feedback) and performance phase (with feedback), both in copy-spelling. For fast flashing spellers, we observed a performance worsening for white icon-speller. Our findings are consistent with existing results reported on end-users using identical white×fast spellers, indicating independence of worsening trend from users' group. The use of slow stimulation timing shed a new light on the perceptual and cognitive phenomena related to the use of a BCI-speller during both the training and the performance phase. We found a significant STIM main effect for the N1 component on P z and PO7 during the training phase and on PO8 during the performance phase, whereas in both phases neither the STIM×COLOR interaction nor the COLOR main effect was statistically significant. After collapsing data for factor COLOR, it emerged a statistically significant modulation of N1 amplitude depending to the phase of BCI session: N1 was more negative for icons than for characters both on P z and PO7 (training), whereas the opposite modulation was observed for PO8 (performance). Results indicate that both feedback and expertise with respect to the stimulus type can modulate the N1 component and that icons require more perceptual analysis. Therefore, fast flashing is likely to be more detrimental for end-users' performance in case of icon-spellers. In conclusion, the interplay between stimulus type and timing seems relevant for a satisfactory and efficient end-user's BCI-experience.
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Affiliation(s)
- Roberta Carabalona
- Biomedical Technological Department, Fondazione Don Carlo Gnocchi Onlus (IRCCS)Milan, Italy
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Kabbara A, Khalil M, El-Falou W, Eid H, Hassan M. Functional Brain Connectivity as a New Feature for P300 Speller. PLoS One 2016; 11:e0146282. [PMID: 26752711 PMCID: PMC4709183 DOI: 10.1371/journal.pone.0146282] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Accepted: 12/14/2015] [Indexed: 01/21/2023] Open
Abstract
The brain is a large-scale complex network often referred to as the "connectome". Cognitive functions and information processing are mainly based on the interactions between distant brain regions. However, most of the 'feature extraction' methods used in the context of Brain Computer Interface (BCI) ignored the possible functional relationships between different signals recorded from distinct brain areas. In this paper, the functional connectivity quantified by the phase locking value (PLV) was introduced to characterize the evoked responses (ERPs) obtained in the case of target and non-targets visual stimuli. We also tested the possibility of using the functional connectivity in the context of 'P300 speller'. The proposed approach was compared to the well-known methods proposed in the state of the art of "P300 Speller", mainly the peak picking, the area, time/frequency based features, the xDAWN spatial filtering and the stepwise linear discriminant analysis (SWLDA). The electroencephalographic (EEG) signals recorded from ten subjects were analyzed offline. The results indicated that phase synchrony offers relevant information for the classification in a P300 speller. High synchronization between the brain regions was clearly observed during target trials, although no significant synchronization was detected for a non-target trial. The results showed also that phase synchrony provides higher performance than some existing methods for letter classification in a P300 speller principally when large number of trials is available. Finally, we tested the possible combination of both approaches (classical features and phase synchrony). Our findings showed an overall improvement of the performance of the P300-speller when using Peak picking, the area and frequency based features. Similar performances were obtained compared to xDAWN and SWLDA when using large number of trials.
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Affiliation(s)
- Aya Kabbara
- Department of electrical and computer engineering, ULFG1, Tripoli, Lebanon
- Azm center for research in biotechnology and its applications, EDST, Tripoli, Lebanon
| | - Mohamad Khalil
- Department of electrical and computer engineering, ULFG1, Tripoli, Lebanon
- Azm center for research in biotechnology and its applications, EDST, Tripoli, Lebanon
| | - Wassim El-Falou
- Department of electrical and computer engineering, ULFG1, Tripoli, Lebanon
- Azm center for research in biotechnology and its applications, EDST, Tripoli, Lebanon
| | | | - Mahmoud Hassan
- INSERM, U1099, F-35000, Rennes, France
- Université de Rennes 1, LTSI, F-35000, Rennes, France
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Guo M, Xu G, Wang L, Masters M, Milsap G, Thakor N, Soares AB. The anterior contralateral response improves performance in a single trial auditory oddball BMI. Biomed Signal Process Control 2015. [DOI: 10.1016/j.bspc.2015.06.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Liu X, Li H, Luo F, Zhang L, Han R, Wang B. Variation of the default mode network with altered alertness levels induced by propofol. Neuropsychiatr Dis Treat 2015; 11:2573-81. [PMID: 26504389 PMCID: PMC4605232 DOI: 10.2147/ndt.s88156] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND The default mode network (DMN) is closely associated with the maintenance of alertness and cognitive functions. This study aimed to observe the changes in DMN induced by increasing doses of propofol and progressively deepening sedation. METHODS Twelve healthy subjects were selected; they received target-controlled infusion of propofol (1.0 and 3.0 μg/mL of plasma) and underwent functional magnetic resonance imaging before sedation and when they achieved light and deep sedation states. The average degree, average shortest path length, global efficiency, local efficiency, and clustering coefficient of DMN were assessed to study the overall and internal changes of DMN with gradual changes in alertness level, as well as the relationship between thalamus and DMN. Meanwhile, basic vital signs and respiratory inhibition were recorded. RESULTS DMN parameters were gradually inhibited with decreasing level of alertness, the differences were significant between light sedation and awake states (all P<0.01), but not between deep and light sedation states. However, the shortest path lengths of the posterior cingulate cortex, medial prefrontal cortex, and lateral parietal cortexes in the DMN were significantly increased under deep sedation. CONCLUSION Overall, DMN is propofol-sensitive. A small dose of propofol can significantly inhibit the DMN, affecting the level of alertness. The posterior cingulate cortex, medial prefrontal cortex, and lateral parietal cortexes in the DMN are less sensitive to propofol, and could be significantly inhibited by a higher concentration of propofol, further reducing the level of alertness.
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Affiliation(s)
- Xiaoyuan Liu
- Department of Anesthesiology, Beijing Tiantan Hospital, Capital Medical University, Beijing, People's Republic of China
| | - Huandong Li
- Brainnetome Center, Institute of Automation, Chinese Academy of Sciences, Capital Medical University, Beijing, People's Republic of China
| | - Fang Luo
- Department of Anesthesiology, Beijing Tiantan Hospital, Capital Medical University, Beijing, People's Republic of China
| | - Lei Zhang
- Department of Neuroradiology, Beijing Neurosurgical Institute, Capital Medical University, Beijing, People's Republic of China
| | - Ruquan Han
- Department of Anesthesiology, Beijing Tiantan Hospital, Capital Medical University, Beijing, People's Republic of China
| | - Baoguo Wang
- Department of Anesthesiology, Sanbo Brain Hospital, Capital Medical University, Beijing, People's Republic of China
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