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Su H, Mao L, Chen X, Liu P, Pu J, Mao Z, Fujiwara T, Ma Y, Mao X, Li T. A Complementary Dual-Mode Ion-Electron Conductive Hydrogel Enables Sustained Conductivity for Prolonged Electroencephalogram Recording. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024:e2405273. [PMID: 39116352 DOI: 10.1002/advs.202405273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2024] [Revised: 07/12/2024] [Indexed: 08/10/2024]
Abstract
Conductive gel interface materials are widely employed as reliable agents for electroencephalogram (EEG) recording. However, prolonged EEG recording poses challenges in maintaining stable and efficient capture due to inevitable evaporation in hydrogels, which restricts sustained high conductivity. This study introduces a novel ion-electron dual-mode conductive hydrogel synthesized through a cost-effective and streamlined process. By embedding graphite nanoparticles into ionic hyaluronic acid (HAGN), the hydrogel maintains higher conductivity for over 72 h, outperforming commercial gels. Additionally, it exhibits superior low skin contact impedance, considerable electrochemical capability, and excellent tensile and adhesion performance in both dry and wet conditions. The biocompatibility of the HAGN hydrogel, verified through in vitro cell viability assays and in vivo skin irritation tests, underscores its suitability for prolonged skin contact without eliciting adverse reactions. Furthermore, in vivo EEG tests confirm the HAGN hydrogel's capability to provide high-fidelity signal acquisition across multiple EEG protocols. The HAGN hydrogel proves to be an effective interface for prolonged high-quality EEG recording, facilitating high-performance capture and classification of evoked potentials, thereby providing a reliable conductive medium for EEG-based systems.
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Affiliation(s)
- Hengjie Su
- Institute of Biomedical Engineering, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, 300192, China
| | - Linna Mao
- Institute of Biomedical Engineering, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, 300192, China
| | - Xiaoqi Chen
- Institute of Biomedical Engineering, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, 300192, China
- Department of Biomedical Engineering, Tiangong University, Tianjin, 300187, China
| | - Peishuai Liu
- Institute of Biomedical Engineering, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, 300192, China
| | - Jiangbo Pu
- Institute of Biomedical Engineering, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, 300192, China
| | - Zhuo Mao
- Institute of Biomedical Engineering, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, 300192, China
| | - Tomoko Fujiwara
- Department of Chemistry, The University of Memphis, Memphis, TN, 38152, USA
| | - Yue Ma
- Institute of Biomedical Engineering, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, 300192, China
| | - Xinyang Mao
- Department of Biomedical Engineering, Tianjin Medical University, Tianjin, 301700, China
| | - Ting Li
- Institute of Biomedical Engineering, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, 300192, China
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Zhang R, Rong R, Gan JQ, Xu Y, Wang H, Wang X. Reliable and fast automatic artifact rejection of Long-Term EEG recordings based on Isolation Forest. Med Biol Eng Comput 2024; 62:521-535. [PMID: 37943419 DOI: 10.1007/s11517-023-02961-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2023] [Accepted: 10/28/2023] [Indexed: 11/10/2023]
Abstract
Long-term electroencephalogram (Long-Term EEG) has the capacity to monitor over a long period, making it a valuable tool in medical institutions. However, due to the large volume of patient data, selecting clean data segments from raw Long-Term EEG for further analysis is an extremely time-consuming and labor-intensive task. Furthermore, the various actions of patients during recording make it difficult to use algorithms to denoise part of the EEG data, and thus lead to the rejection of these data. Therefore, tools for the quick rejection of heavily corrupted epochs in Long-Term EEG records are highly beneficial. In this paper, a new reliable and fast automatic artifact rejection method for Long-Term EEG based on Isolation Forest (IF) is proposed. Specifically, the IF algorithm is repetitively applied to detect outliers in the EEG data, and the boundary of inliers is promptly adjusted by using a statistical indicator to make the algorithm proceed in an iterative manner. The iteration is terminated when the distance metric between clean epochs and artifact-corrupted epochs remains unchanged. Six statistical indicators (i.e., min, max, median, mean, kurtosis, and skewness) are evaluated by setting them as centroid to adjust the boundary during iteration, and the proposed method is compared with several state-of-the-art methods on a retrospectively collected dataset. The experimental results indicate that utilizing the min value of data as the centroid yields the most optimal performance, and the proposed method is highly efficacious and reliable in the automatic artifact rejection of Long-Term EEG, as it significantly improves the overall data quality. Furthermore, the proposed method surpasses compared methods on most data segments with poor data quality, demonstrating its superior capacity to enhance the data quality of the heavily corrupted data. Besides, owing to the linear time complexity of IF, the proposed method is much faster than other methods, thus providing an advantage when dealing with extensive datasets.
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Affiliation(s)
- Runkai Zhang
- Key Laboratory of Child Development and Learning Science of Ministry of Education, School of Biological Science & Medical Engineering, Southeast University, Nanjing, 210096, Jiangsu, People's Republic of China
| | - Rong Rong
- Department of Neurology, Nanjing Drum Tower Hospital, Nanjing, 210008, Jiangsu, People's Republic of China
| | - John Q Gan
- School of Computer Science and Electronic Engineering, University of Essex, Colchester, CO4 3SQ, UK
| | - Yun Xu
- Department of Neurology, Nanjing Drum Tower Hospital, Nanjing, 210008, Jiangsu, People's Republic of China
| | - Haixian Wang
- Key Laboratory of Child Development and Learning Science of Ministry of Education, School of Biological Science & Medical Engineering, Southeast University, Nanjing, 210096, Jiangsu, People's Republic of China.
| | - Xiaoyun Wang
- Department of Neurology, Nanjing Drum Tower Hospital, Nanjing, 210008, Jiangsu, People's Republic of China.
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Detection of muscle artifact epochs using entropy based M-DDTW technique in EEG signals. Biomed Signal Process Control 2021. [DOI: 10.1016/j.bspc.2021.102653] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Jakab A, Kulkas A, Salpavaara T, Kauppinen P, Verho J, Heikkilä H, Jäntti V. Novel wireless electroencephalography system with a minimal preparation time for use in emergencies and prehospital care. Biomed Eng Online 2014; 13:60. [PMID: 24886096 PMCID: PMC4036392 DOI: 10.1186/1475-925x-13-60] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Accepted: 03/24/2014] [Indexed: 12/01/2022] Open
Abstract
Background Although clinical applications such as emergency medicine and prehospital care could benefit from a fast-mounting electroencephalography (EEG) recording system, the lack of specifically designed equipment restricts the use of EEG in these environments. Methods This paper describes the design and testing of a six-channel emergency EEG (emEEG) system with a rapid preparation time intended for use in emergency medicine and prehospital care. The novel system comprises a quick-application cap, a device for recording and transmitting the EEG wirelessly to a computer, and custom software for displaying and streaming the data in real-time to a hospital. Bench testing was conducted, as well as healthy volunteer and patient measurements in three different environments: a hospital EEG laboratory, an intensive care unit, and an ambulance. The EEG data was evaluated by two experienced clinical neurophysiologists and compared with recordings from a commercial system. Results The bench tests demonstrated that the emEEG system's performance is comparable to that of a commercial system while the healthy volunteer and patient measurements confirmed that the system can be applied quickly and that it records quality EEG data in a variety of environments. Furthermore, the recorded data was judged to be of diagnostic quality by two experienced clinical neurophysiologists. Conclusions In the future, the emEEG system may be used to record high-quality EEG data in emergency medicine and during ambulance transportation. Its use could lead to a faster diagnostic, a more accurate treatment, and a shorter recovery time for patients with neurological brain disorders.
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Affiliation(s)
- Andrei Jakab
- Department of Electronics and Communications Engineering, Tampere University of Technology, Korkeakoulunkatu 3, FI-33720 Tampere, Finland.
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Video-electroencephalography investigation of ictal alterations of consciousness in epilepsy and nonepileptic attack disorder: practical considerations. Epilepsy Behav 2014; 30:24-7. [PMID: 24113568 DOI: 10.1016/j.yebeh.2013.09.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2013] [Accepted: 09/04/2013] [Indexed: 11/24/2022]
Abstract
The ictal assessment of consciousness is of central importance in the differential diagnosis of epilepsy and nonepileptic attack disorder (NEAD). Long-term video-electroencephalography (video-EEG) is currently considered the gold standard investigative technique for the evaluation of patients with recurrent attacks associated with transient alterations of arousal (responsiveness) and/or awareness (experiential states). This paper offers a concise review focusing on the practical aspects of clinical relevance in the video-EEG diagnostic workout of inpatients with suspected epilepsy or NEAD, as outlined in existing guidelines and recommendations. The reviewed literature implies that both implementation of specific procedures (e.g., activation maneuvers) and interpersonal approach (e.g., monitoring protocols) during video-EEG should be tailored to the individual patient's presentation.
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Wijnberg ID, van der Ree M, van Someren P. The applicability of ambulatory electroencephalography (AEEG) in healthy horses and horses with abnormal behaviour or clinical signs of epilepsy. Vet Q 2013; 33:121-31. [PMID: 24111950 DOI: 10.1080/01652176.2013.842075] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Abstract
BACKGROUND Short-duration electroencephalography (EEG) recordings in horses are helpful in diagnosing intracranial disorders. Potentially, long-duration ambulatory EEG (AEEG) recordings in horses will enhance the chance of detecting abnormal brain activity independent of the presence of an insult. OBJECTIVE The objective of this study was to test if AEEG recordings in unsedated horses can be acquired and benefit diagnosing abnormal brain activity. ANIMALS AND METHODS Recordings were taken from 8 adult control horses and 10 patients suspected of intracranial abnormalities. Self-adhesive electrodes and the 'Porti-5' recording system were used. Filter settings were 0.5 Hz high pass and 35 Hz low pass. The records were analysed offline at a 50-200 μV/division and 10 seconds/division scale. Abnormal activity was defined as a spike or sharp wave, a period of generalised slow wave rhythmical activity or a generalised fast rhythmical discharge. The recording time ranged from 5 to 49 hours. RESULTS In the control group, one horse showed pathological activity. In the patient group, six out of nine horses showed abnormal activity during the recordings. Magnetic resonance imaging confirmed the presence of an intracranial mass in one patient. Long-term recordings of high quality can be obtained in unsedated horses by allowing daily activity using AEEG, resulting in a reasonable chance of recording (inter)ictal abnormal brain activity indicating epileptic or seizure-like activity in the absence of clinical signs or seizures. CONCLUSIONS It is concluded that abnormal behaviour can be expressed intermittently, and with the availability of AEEG a useful tool is added to the diagnostic scenario for horses.
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Affiliation(s)
- I D Wijnberg
- a Department of Equine Sciences, Faculty of Veterinary Medicine , Utrecht University , Utrecht , The Netherlands
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İpekdal İH, Karadaş Ö, Ulaş ÜH, Vural O. Can cortical silent period and motor threshold be practical parameters in the comparison of patients with generalized epilepsy and patients with psychogenic non-epileptic seizures? Eur Neurol 2012; 69:41-7. [PMID: 23128038 DOI: 10.1159/000342898] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Accepted: 08/21/2012] [Indexed: 11/19/2022]
Abstract
BACKGROUND/AIM This study aimed to compare the cortical excitability of patients with generalized tonic-clonic seizures (GTCSs) and that of patients with psychogenic non-epileptic seizures (PNESs). METHODS Patients were classified into groups according to their electroencephalogram (EEG) findings and seizure types: group 1 = GTCS with an abnormal EEG, group 2 = GTCS with a normal EEG and group 3 = PNES with a normal EEG. The control group included healthy volunteers with normal EEGs. Cortical silent period (CSP) and motor threshold (MT) were measured for all groups and the results were compared. RESULTS CSPs were significantly prolonged in groups 1 and 2 when compared with group 3 and the control group. No differences were found between the MT measurements of all groups. CONCLUSION The prolongation of CSP may demonstrate the differences between the pathophysiological mechanisms of GTCS and those of PNES.
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Affiliation(s)
- İlker H İpekdal
- Department of Neurology, Near East University Hospital, Nicosia, Cyprus. ipekdal @ yahoo.com
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Abstract
Artifacts may be obtained during routine recording but are more common in special care units (SCUs) outside of the EEG laboratory, where complex electrical currents are present that create a "hostile" environment. Special care units include the epilepsy monitoring unit, neurologic intensive care unit, and operating room, where artifact is present in virtually every recording, increasing with prolonged use. Nonepileptic attacks treated as epileptic seizures have been incorrectly diagnosed and treated due to a misinterpreted EEG. The recent emergence of continuous EEG as a neurophysiologic surrogate for brain function in the neurologic intensive care unit and operating room has also brought a greater amount and new types of EEG artifact. The artifacts encountered in special care units during continuous EEG are becoming more complex and may have adverse therapeutic implications. Our knowledge of artifact needs to parallel our growth in technology to avoid the pitfalls that may be incurred during visual analysis of the EEG.
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Leiser SC, Dunlop J, Bowlby MR, Devilbiss DM. Aligning strategies for using EEG as a surrogate biomarker: A review of preclinical and clinical research. Biochem Pharmacol 2011; 81:1408-21. [DOI: 10.1016/j.bcp.2010.10.002] [Citation(s) in RCA: 96] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2010] [Revised: 10/01/2010] [Accepted: 10/01/2010] [Indexed: 11/30/2022]
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Tatum WO, Husain AM, Benbadis SR, Kaplan PW. Normal adult EEG and patterns of uncertain significance. J Clin Neurophysiol 2006; 23:194-207. [PMID: 16751720 DOI: 10.1097/01.wnp.0000220110.92126.a6] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
A thorough understanding of a normal EEG is critical in defining those patterns that are abnormal. Because EEG is unique in the ability to support a clinical diagnosis of epilepsy, epileptiform patterns merit careful consideration. Certain benign patterns maybe epileptiform, yet can occur in healthy individuals without epilepsy. Understanding normal EEG and the benign variants will help to minimize over-interpretation and possibly avoid overtreatment of patients during routine clinical practice.
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Affiliation(s)
- William O Tatum
- Department of Neurology, Tampa General Hospital, University of South Florida, Tampa, Florida 33613, USA.
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Drenthen J, van Hulst RA, Blok JH, van Heel MD, Haitsma JJ, Lachmann B, Visser GH. Quantitative EEG Monitoring During Cerebral Air Embolism and Hyperbaric Oxygen Treatment in a Pig Model. J Clin Neurophysiol 2003; 20:264-72. [PMID: 14530740 DOI: 10.1097/00004691-200307000-00006] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The purpose of this study was to evaluate the contribution of quantitative EEG (qEEG) to an animal model of cerebral air embolism (CAE). In 12 anesthetized pigs, air was injected into the internal carotid artery, and hyperbaric oxygen (HBO) treatment was started either after 3 minutes or after 60 minutes (United States Navy Treatment Table 6). Off-line spectral analysis was used to determine the frequency content of the EEG signal, and factor analysis was performed to determine the frequency ranges that optimally showed the changes in the power spectrum. Factor analysis revealed two factors that represented different and independent spectral changes during embolization: 0.5 to 7.3 Hz (band 1) and 26.4 to 30.3 Hz (band 2). Shortly after embolization, the power in both bands decreased to a minimum, representing an isoelectric EEG in 11 out of the 12 animals. EEG differences between animals were considerable, despite standardized doses of injected air, and qEEG can objectively assess and quantify these differences in immediate impact of air embolism on brain function. Also, qEEG enabled monitoring of the recovery from the initial embolic event and of the response on treatment. The initial recovery was much more protracted in band 2 than in band 1, but even after completing HBO treatment, qEEG values did not return to baseline values in all animals. In addition, two animals did not survive until the end of the HBO treatment, and qEEG proved to be superior to the other measured hemodynamic variables to detect and ensure a deterioration of brain function. This study showed that qEEG monitoring has significant additional value to monitoring HBO treatment.
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Affiliation(s)
- Judith Drenthen
- Department of Neurology/Clinical Neurophysiology, Erasmus Medical Center Rotterdam, The Netherlands
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Abstract
CONTEXT Electronic medical devices (EMDs) with downloadable memories, such as implantable cardiac pacemakers, defibrillators, drug pumps, insulin pumps, and glucose monitors, are now an integral part of routine medical practice in the United States, and functional organ replacements, such as the artificial heart, pancreas, and retina, will most likely become commonplace in the near future. Often, EMDs end up in the hands of the pathologist as a surgical specimen or at autopsy. No established guidelines for systematic examination and reporting or comprehensive reviews of EMDs currently exist for the pathologist. OBJECTIVE To provide pathologists with a general overview of EMDs, including a brief history; epidemiology; essential technical aspects, indications, contraindications, and complications of selected devices; potential applications in pathology; relevant government regulations; and suggested examination and reporting guidelines. DATA SOURCES Articles indexed on PubMed of the National Library of Medicine, various medical and history of medicine textbooks, US Food and Drug Administration publications and product information, and specifications provided by device manufacturers. STUDY SELECTION Studies were selected on the basis of relevance to the study objectives. DATA EXTRACTION Descriptive data were selected by the author. DATA SYNTHESIS Suggested examination and reporting guidelines for EMDs received as surgical specimens and retrieved at autopsy. CONCLUSIONS Electronic medical devices received as surgical specimens and retrieved at autopsy are increasing in number and level of sophistication. They should be systematically examined and reported, should have electronic memories downloaded when indicated, will help pathologists answer more questions with greater certainty, and should become an integral part of the formal knowledge base, research focus, training, and practice of pathology.
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Affiliation(s)
- James B Weitzman
- Department of Pathology, SUNY Downstate Medical Center, Brooklyn, NY 11203, USA.
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