Independent Component Analysis: Here we adapted the FastICA algorithm to implement ICA in our research as mentioned in the chapters before. It extracted the following component maps for a summary view of the activity power spectrum and event - related data epochs. The 2D component map is shown in Fig. 9.
To plot maps of 2-D scalp components, select Plot -> Component maps -> In 2D. Pop topoplot.m will then generate the animated window. The popup window we used to plot ERP scalp maps is very similar.
Blinks and artifacts identification: Fig. 10. Shows IC1 representing blinks in the spectrum.
For three factors, this Fig. 10 can be recognized as an eye artifact: (1) A typical eye artifact has the smoothly decreasing EEG spectrum like the one displayed; (2) The scalp shows a powerful, far - front visualization typical that of an eye artifact; And, (3) Individual eye movements can be seen in the erpimage.m aspect
Eye objects are almost always present in EEG datasets. They are usually found near the top of the collection of components and contour maps of the scalp. Component property figures can also be accessed directly by choosing Plot —> Component properties. The single component 1 is shown in Fig. 10 with a clear frontal eye movement projection. Several eye blinks were saved because they're one of the most important parts of our research. Most of the objects are dismissed or decayed based on the severity of their errors. Individual data components with blinking elements (see Fig. 11) and cross coherence (see Fig. 12).
One EEG was collected while the individual was engaged in a challenging cognitive task and compared to a control data set collected when the person was in a less reflective role. The blinking rate of subjects performing cognitive tasks decreased significantly from 19 to 15 in signals obtained from them. After counting the blinks in our data sets, we noticed a strong difference between the blinks caused by a more attentive task and the blinks caused by a less attentive task. On the power spectral density estimates, it can also be seen that power is most prevalent in the alpha frequency region and gradually decreases as the frequency increases. Furthermore, the spectral analysis is useful.
An Event-Related Potentials (ERP) is also analyzed (see Fig. 13). From the above results, it can therefore be deduced that blinking rates decrease when conducting a conscientious task on Video Display Terminals (VDT), which will help spur eyestrain — a major symptom of CVS. High attention in the use of VDT is therefore directly linked with CVS. The component Activity IC14 and Standard Normal Quantities is shown in Fig. 14. Finally the Power spectral density for components are shown in Fig. 15.
Power Spectral density
Average power of a signal x(t) for the total time is given by the succeeding time average
EEG data and alcoholism
Colrain analyzed 42 long-term alcoholics (27 males) and 42 controls (19 males) in a clinical study in 2009 [24]. According to Nicholas and Trinder's study [25], alcoholics were significantly less likely than controls to produce K-complexes. Despite this, the amplitude of P2 was lower in abusers than in controls, with the largest difference in Cz, alcoholics' P2 latency was longer [25]. There were no gender differences or relationships between screening and sex for K-complex occurrence, P2 amplitude, or P2 latency. Heavy drinkers had lower frontal amplitudes of N550 and P900 than controls, and males had lower frontal amplitudes than females, but the gender difference was not important ( see Fig. 16).
As a result, this research shows that long-term alcohol dependence is linked to a reduced capacity to produce evoked delta waveform responses as well as a smaller response order of magnitude when evoked (weaker N550 and P900 amplitudes). The resting EEG is a transcript of current nervous system electrical impulses recorded while the subject is in a relaxed state. It is made up of oscillations with a frequency defined as the number of times a wave completes its loop in one unit of time. By the magnitude of their voltage, EEG variations are often calculated in microvolts (V) (power).
EEGs are typically classified into five frequencies: Delta (3Hz or less), Theta (3.5–7.5Hz), Alpha (8.0–11.5 Hz), Beta (between 12 and 28 Hz), and Gamma (between 28.5 and 50.0 Hz), with each frequency indicating a different degree of cognitive activity. Via safe adult lives, the EEG remains stable and highly heritable [26]. Alcoholics have irregular resting EEGs and ERPs, according to this study. Often, explore the significance of the findings. Tonic theta levels have been shown to rise in many brain conditions, including Alzheimer's disease, and to rise with reduced brain activity, according to neuroscientists. The Collaborative Study on Alcohol Genetics (COGA) looked into alcoholics' tonic theta capacity. The incidence of eye-closed resting theta in 307 people who participated in the alcohol-dependent survey and 307 people who were matched by sex in a study [27]. The alcohol-dependent group had higher resting theta in all scalp locations. Increased tonic theta intensity in the EEG can suggest a problem with cognition ability in the Central Nervous System (CNS) [28]. Theta capacity at rest increased with age, and also in Alzheimer's patients [28]. Another possible rise in theta may be a neurophysiological sign of a cortical imbalance in the balance of excitatory and inhibitory neurons [28].
In a relaxed human, the alpha rhythm is the highest of all frequencies. It can be seen when the eyes are open or closed, and it is greatest over the occipital region of the brain when the eyes are closed. The alpha frequency is a calming factor. Several major studies, dating back to the mid-19th century, have shown that alcohol abusers have unbalanced or low alpha capacity. Initial research suggested that addicts had lower alpha capacity than non-addicts [30], but more recent research contradicts this [29]. Enoch and his team discovered that an alpha rhythm, specifically Low Voltage Alpha (LVA. T), was linked to an alcohol dependence co-subtype occurring with social anxiety. The authors believe that the effect of altered NE levels on thalamus stimulation (a nervous system messaging facility) can explain some of the links between LVA, anxiety, and alcoholism. (a nervous system messaging system) may clarify some of the connections between LVA, anxiety, and alcoholism. [23.]
EEG data and Media Addicts:
When it comes to Media Obsessed people, we've done a lot of electroencephalogram data analysis. We discovered some strong findings about theta and alpha frequencies of addicts as compared to non-addicts. Since addict research has suggested that abusers have low alpha and high theta, the same has been applied to the measurement of all subjects' median alpha and theta frequency bands. In the occipital region of addicted subjects, a whole pattern in alpha and theta signals was discovered to be dominant and peculiar compared to the other frequencies. We may infer from other analytics we performed, such as eye blink rate and human attention, that performing attentive tasks on digital screens causes a decrease in eye blink rate (EBR), which leads to the fundamental symptom of eye strain computer vision syndrome (CVS). Overall trend of Alpha & Theta of Media Addicted vs non-Addicted are shown in Fig. 17. The same data also can be explained through the Table 1. It is observed that addicted signals are always higher frequencies (in Hz) than the normal behavior.
Power Spectrum Analysis:
We determined the spectral density to consider the power signal distribution in the frequency domain. To get such, the Fourier transform was used. We discovered that the power of addicts was significantly higher than that of non-addicts, especially in the occipital region of the brain. Even though the power was higher in all areas of the brain, the occipital region showed a noticeable difference. The spectrograms and power spectral analysis are shown in the Fig. 18–20. Power spectrum for channel 8 to channel 1 are shown in Fig. 18, the Trend graph are shown in Fig. 19, and Spectrograms are shown in Fig. 20.
We used Python's matplot.lib and MATLAB's EEGLAB to plot the power spectrums, trend graphs, and spectrograms. We calculated the absolute values for the frequency bands Alpha, Theta, and Beta of the EEGs in Table 1 using these. The overall pattern of Alpha and Theta was found to be similar to that of alcoholics. When digital displays are removed from the equation, the results appear to change.