ARTICLE | doi:10.20944/preprints202203.0145.v1
Subject: Medicine & Pharmacology, Behavioral Neuroscience Keywords: electroencephalography (EEG); EEG bands; decision tree; machine learning
Online: 10 March 2022 (10:38:44 CET)
Electroencephalography (EEG) is a brain imaging technique in which electrodes are placed on the scalp. EEG signals are commonly decomposed into frequency bands called delta, theta, alpha, and beta.While these bands have been shown to be useful for characterizing various brain states, their utility as a one-size-fits-all analysis tool remains unclear. We present a two-part data-driven methodology for objectively determining the best EEG bands for a given dataset in this paper. First, a decision tree is used to estimate the optimal frequency band boundaries for reproducing the signal’s power spectrum for a predetermined number of bands. The optimal number of bands is then determined using an Akaike Information Criterion (AIC)-inspired quality score that balances goodness-of-fit with a small band count. Data-driven EEG band discovery may aid in objectively capturing key signal components and uncovering new indices of brain activity.
ARTICLE | doi:10.20944/preprints202108.0342.v1
Subject: Behavioral Sciences, Behavioral Neuroscience Keywords: integrated information theory; Lempel-Ziv complexity; multichannel EEGs; Electroencephalography; measures of consciousness
Online: 16 August 2021 (13:52:06 CEST)
Multichannel EEGs were obtained from healthy participants in the eyes-closed no-task condition (where the alpha component is typically abolished). EEG dynamics in the two conditions were quantified with two related binary Lempel-Ziv measures of the first principal component and with three measures of integrated information including the more recently proposed integrated synergy. Both integrated information and integrated synergy with model order p=1 had greater values in the eyes closed condition. If the model order of integrated synergy was determined with the Bayesian Information Criterion, this pattern was reversed, and in common with other measures, integrated synergy was greater in the eyes open condition. Eyes open versus eyes closed separation was quantified by calculation of the between-condition effect size. Lempel-Ziv complexity of the first principal component showed greater separation than the measures of integrated information. The performance of the integrated information measures investigated here when distinguishing between indisputably different physiological states encourages caution when advocating for their use as measures of consciousness.
REVIEW | doi:10.20944/preprints202103.0555.v1
Subject: Engineering, Automotive Engineering Keywords: dry EEG; dry EEG electrode; dry electrode; electroencephalography; non-contact electrode EEG
Online: 23 March 2021 (08:56:57 CET)
The basis of the work of electroencephalography (EEG) is the registration of electrical impulses from the brain or some of its individual areas using a special sensor/electrode. This method is used for the treatment and diagnosis of various diseases. The use of wet electrodes in this case does not seem viable, for several well-known reasons. As a result of this, a detailed analysis of modern EEG sensors developed over the past few years is carried out, which will allow researchers to choose this type of sensor more carefully and, as a result, conduct their research more competently. Due to the absence of any standards in the production and testing of dry EEG sensors, the main moment of this manuscript is a detailed description of the necessary steps for testing a dry electrode, which will allow researchers to maximize the potential of the sensor in the various type of research.
ARTICLE | doi:10.20944/preprints202111.0345.v1
Subject: Engineering, Biomedical & Chemical Engineering Keywords: brain-computer interface (BCI); electroencephalography (EEG); stress state recognition; feature selection; particle swarm optimization (PSO); mRMR; SVM; DEEP; SEED
Online: 19 November 2021 (11:01:19 CET)
Mental stress state recognition using electroencephalogram (EEG) signals for real-life applications needs a conventional wearable device. This requires an efficient number of EEG channels and an optimal feature set. The main objective of the study is to identify an optimal feature subset that can best discriminate mental stress states while enhancing the overall performance. Thus, multi-domain feature extraction methods were employed, namely, time domain, frequency domain, time-frequency domain, and network connectivity features, to form a large feature vector space. To avoid the computational complexity of high dimensional space, a hybrid feature selection (FS) method of minimum Redundancy Maximum Relevance with Particle Swarm Optimization and Support Vector Machine (mRMR-PSO-SVM) is proposed to remove noise, redundant, and irrelevant features and keep the optimal feature subset. The performance of the proposed method is evaluated and verified using four datasets, namely EDMSS, DEAP, SEED, and EDPMSC. To further consolidate, the effectiveness of the proposed method is compared with that of the state-of-the-art heuristic methods. The proposed model has significantly reduced the features vector space by an average of 70% in comparison to the state-of-the-art methods while significantly increasing overall detection performance.
ARTICLE | doi:10.20944/preprints202008.0159.v1
Subject: Mathematics & Computer Science, Analysis Keywords: Diseases; electrocardiography; electroencephalography; Timed-Up and Go test; sensors; mobile devices; feature detection; diseases; older adults
Online: 6 August 2020 (10:46:57 CEST)
The use of smartphones, coupled with different sensors, makes it an attractive solution for measuring different physical and physiological features, allowing for the monitoring of various parameters and even identifying some diseases. The BITalino device allows the use of different sensors, including Electroencephalography (EEG) and Electrocardiography (ECG) sensors, to study different health parameters. With these devices, the acquisition of signals is straightforward, and it is possible to connect them using a Bluetooth connection. With the acquired data, it is possible to measure parameters such as calculating the QRS complex and its variation with ECG data to control the individual's heartbeat. Similarly, by using the EEG sensor one could analyze the individual's brain activity and frequency. The purpose of this paper is to present a method for recognition of the diseases related to ECG and EEG data, with sensors available in off-the-shelf mobile devices and sensors connected to a BITalino device. The data were collected during the elderly's experiences, performing the Timed-Up and Go test, and the different diseases found in the sample in the study. The data were analyzed, and the following features were extracted from the ECG, including heart rate, heart rate variability, the average QRS interval, the average R-R interval, and the average R-S interval, and the EEG, including frequency and variability. Finally, the diseases are correlated with different parameters, proving that there are relations between the individuals and the different health conditions.
ARTICLE | doi:10.20944/preprints201906.0122.v1
Subject: Behavioral Sciences, Cognitive & Experimental Psychology Keywords: music; language; syntax; attention; comprehension; electroencephalography; event-related potentials
Online: 13 June 2019 (13:13:57 CEST)
Music and language are hypothesized to share neural resources, particularly at the level of syntax processing. Recent reports suggest that attention modulates this sharing of neural resources, but the time-course of the effects of attention, and the degree to which attention operates similarly on music and language, are yet unclear. In this EEG study we manipulate the syntactic structure of simultaneously presented musical chord progressions and garden-path sentences in a modified rapid serial visual presentation paradigm, while varying top-down attentional demands to the two modalities. The Early Right Anterior Negativity (ERAN) was observed in response to both attended and unattended musical syntax violations. In contrast, an N400 was only observed in response to attended linguistic syntax violations, and a P3 only in response to attended musical syntax violations. Results show that top-down allocation of attention indeed affects the processing of syntax in both music and language, with different neural resources acting upon the two modalities particularly at later stages of cognitive processing. However, the processing of musical syntax at an earlier stage of the perceptual-cognitive pathway, as indexed by the ERAN, is partially automatic, and is strongly indicative of separate neural resources for music and language.
ARTICLE | doi:10.20944/preprints202203.0257.v1
Subject: Medicine & Pharmacology, Psychiatry & Mental Health Studies Keywords: biomarkers; electroencephalography; event related potentials; heart rate variability; diagnosis; sensitivity; specificity
Online: 17 March 2022 (15:19:38 CET)
The combination of statistical learning technologies with large databases of psychophysiological data has appropriately generated enthusiastic interest in future clinical applicability. It is argued here that this enthusiasm should be tempered with the understanding that significant obstacles must be overcome before the systematic introduction of psychophysiological measures into neuropsychiatric practice becomes possible. The nonspecificity of psychophysiological measures complicates their use in diagnosis. Low test-retest reliability complicates use in longitudinal assessment, and quantitative psychophysiological measures can normalize in response to placebo intervention. Ten cautionary observations are introduced and, in some instances, possible directions for remediation are suggested.
ARTICLE | doi:10.20944/preprints202208.0346.v1
Subject: Behavioral Sciences, Cognitive & Experimental Psychology Keywords: ambient light; reliability; take-over request; mental workload; electroencephalography (EEG); transition of control
Online: 18 August 2022 (11:02:56 CEST)
Drivers of L3 automated vehicles (AVs) are not required to continuously monitor the AV system. However, they must be prepared to take over when requested. Therefore, it is necessary to design an in-vehicle environment that allows drivers to adapt their levels of preparedness to the likelihood of control transition. This study evaluates ambient in-vehicle lighting that continuously communicates the current level of AV reliability, specifically on how it could influence drivers' take-over performance and mental workload (MW). We conducted an experiment in a driving simulator with 42 participants who experienced 10 take-over requests (TORs). The experimental group experienced a four-stage ambient light display that communicated the current level of AV reliability, which was not provided to the control group. The experimental group demonstrated better take-over performance, based on lower vehicle jerks. Notably, perceived MW did not differ between the groups, and the EEG indices of MW (frontal theta power, parietal alpha power, Task-Load Index) did not differ between the groups. These findings suggest that communicating the current level of reliability using ambient light might help drivers be better prepared for TORs and perform better without increasing their MW.
ARTICLE | doi:10.20944/preprints202105.0473.v1
Subject: Behavioral Sciences, Behavioral Neuroscience Keywords: inhibitory control; executive function; event-related potentials; electroencephalography; N200; P300; cognitive aging; neural recruitment
Online: 20 May 2021 (10:18:16 CEST)
Aging is accompanied by frontal lobe and non-dominant hemisphere recruitment that supports executive functioning, such as inhibitory control, which is crucial to all cognitive functions. Yet, the spatio-temporal sequence of processing underlying successful inhibition and how it changes with age is understudied. Thus, we assessed N200 (conflict monitoring) and P300 (response inhibition, performance evaluation) event-related potentials (ERPs) in young and healthy older adults during comparably performed successful stop-signal inhibition. We additionally interrogated the continuous spatio-temporal dynamics of N200- and P300-related activation within each group. Young adults had left hemisphere dominant N200, while older adults had overall larger amplitudes and right hemisphere dominance. N200 activation was biphasic in both groups but differed in scalp topography. P300 also differed, with larger right amplitudes in young, but bilateral amplitudes in old, with old larger than young in the left hemisphere. P300 was characterized by an early parieto-occipital peak in both groups, followed by a parietal slow wave only in older adults. A temporally similar but topographically different final wave followed in both groups that showed anterior recruitment in older adults. These findings illuminate differential age-related spatio-temporal recruitment patterns for conflict monitoring and response inhibition that are critically important for understanding age-related compensatory activation.
ARTICLE | doi:10.20944/preprints202012.0527.v1
Subject: Mathematics & Computer Science, Algebra & Number Theory Keywords: epilepsy; seizure detection; electroencephalography; classification with a deferral option; home monitoring; long-term monitoring; wearables
Online: 21 December 2020 (13:40:43 CET)
Wearable technology will become available and allow prolonged electroencephalography (EEG) monitoring in the home environment of patients with epilepsy. Neurologists analyse the EEG visually and annotate all seizures, which patients often under report. Visual analysis of a 24 hour EEG recording typically takes one to two hours. Reliable automated seizure detection algorithms will be crucial to reduce this analysis. We study a dataset of behind-the-ear EEG measurements. Our first aim was to develop a methodology to reduce the EEG dataset by classifying part of the data automatically, while retaining 100% detection sensitivity (DS). Prediction confidences are determined by temperature scaling of the classification model outputs and trust scores. A DS of approximately 90% (99%) can be achieved when automatically classifying around 90% (60%) of the data. Perfect DS can be achieved when automatically classifying 50% of the data. Our second contribution demonstrates that a common modelling strategy, where predictions from several short EEG segments are used to obtain a final prediction, can be improved by filtering out untrustworthy segments with low trust scores. The false detection rate shows a relative decrease between 21% and 43%, and the DS shows a small increase or decrease.
CASE REPORT | doi:10.20944/preprints202004.0443.v1
Subject: Keywords: traumatic brain injury (TBI); Dysarthria; transcranial direct current stimulation (tDCS); Quantitative Electroencephalography (QEEG); speech therapy
Online: 24 April 2020 (13:56:38 CEST)
Purpose: Dysarthria, a neurological injury of the motor component of the speech circuitry, is of common consequences of traumatic brain injury (TBI). Palilalia is a speech disorder characterized by involuntary repetition of words, phrases, or sentences. Based on the evidence supporting the effectiveness of transcranial direct current stimulation (tDCS) in some speech and language disorders, we hypothesized that using tDCS would enhances the effectiveness of speech therapy in a client with chronic dysarthria following TBI. Method: We applied the constructs of the “Be Clear” protocol, a relatively new approach in speech therapy in dysarthria, together with tDCS on a chronic subject who affected by dysarthria and palilalia after TBI. Since there was no research on the use of tDCS in such cases, regions of interest (ROIs) were identified based on deviant brain electrophysiological patterns in speech tasks and resting state compared with normal expected patterns using the Quantitative Electroencephalography (QEEG) analysis. Results: Measures of perceptual assessments of intelligibility, an important index in the assessment of dysarthria, were superior to the primary protocol results immediately and 4 months after intervention. We did not find any factor other than the use of tDCS to justify this superiority. The percentage of repeated words, an index in palilalia assessment, had a remarkable improvement immediately after intervention but fell somewhat after 4 months. We justified this case with subcortical origins of palilalia. Conclusion: Our present case-based findings suggested that applying tDCS together with speech therapy may improve intelligibility in similar case profiles as compared to traditional speech therapy. To reconfirm the effectiveness of the above approach in cases with dysarthria following TBI, more investigation need to be pursued.