Towards the Real-Life EEG Applications: Practical Problems and Preliminary Solutions

Towards the Real-Life EEG Applications: Practical Problems and Preliminary Solutions

Guangyi Ai (Neusoft Institute Guangdong, China)
Copyright: © 2019 |Pages: 13
DOI: 10.4018/978-1-5225-7879-6.ch014

Abstract

Electroencephalogram (EEG) is one of the most popular approaches for brain monitoring in many research fields. While the detailed working flows for in-lab neuroscience-targeted EEG experiments conditions have been well established, carrying out EEG experiments under a real-life condition can be quite confusing because of various practical limitations. This chapter gives a brief overview of the practical issues and techniques that help real-life EEG experiments come into being, and the well-known artifact problems for EEG. As a guideline for performing a successful EEG data analysis with the low-electrode-density limitation of portable EEG devices, recently proposed techniques for artifact suppression or removal are briefly surveyed as well.
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Introduction

Understanding how the brain works and responds to stimuli of interest under specified contexts plays a significantly important role in various research fields from fundamental neuroscience researches to complicated social behavioral topics. In many researches, since no clear answers can be effectively obtained, a deep-going analysis based on objective, quantitative, and context-dependent brain states turns into the key for further uncovering the essential parts of the research topics. Yet, monitoring brain states and activities is still remaining a challenge. While brain monitoring techniques and corresponding standard working flows have been well established for in-lab neuroscience researches, when carrying out social or behavioral tasks under a real-life condition, special care must be kept in mind because of a number of practical and technical limitations. This chapter reviews the techniques targeted to the real-life applications of EEG, and briefly marks the practical problems should be aware of, thus makes a preliminary guideline for the EEG applications under real-life environments.

Background

In conjunction with the rapid development of sensors and electronic systems, epoch-making techniques for brain state monitoring have been brought onto the frontal stage and widely used in various research fields. Relying on disparate principles, brain states and neuron activities can be observed from different viewpoints. Among those techniques, EEG has gained increasing attention and become popular in various research topics. However, the use of EEG also has its own limitations. In practice, the experimental condition for EEG applications under an open real-world environment is hugely different from the in-lab setups for standard neuroscience researches, and portable EEG measurements are usually preferred. Thus, the practical issues and solutions to real-life portable EEG applications should be taken into account.

Why EEG?

To measure brain activities or responses to specific stimuli, a number of techniques can be adopted. In dependence on the fact that neuronal activities are associated with changes in cerebral blood flow, functional magnetic resonance (fMRI) measures brain activity using blood-oxygen-level dependent (BOLD) contrast. In comparison with a predefined control state, detections for increased brain activities can be obtained with a high spatial resolution. Magnetoencephalography (MEG) is another leading neuroimaging technique to specify activated brain regions deep inside using sensitive magnetometers that can catch magnetic field changes caused by electrical activities taking place inside the brain. These techniques provide extraordinary information for brain states estimation, and have been widely used in various brain related researches. However, both of them must be taken with unportable, huge, expensive apparatus, which imposes strong constraints to its applications and experimental task design. Near-infrared spectroscopy (NIRS) is a new optical imaging technology, which is possible to be miniaturized for portable use and having an extra advantage of interference-free against other electric activities, such as activities caused by muscle movements. But its conspicuous disadvantages of limited spatial and temporal resolutions are usually negatively concerned as a limitation to real-life portable applications. Electroencephalography (EEG), which is firstly recorded by Hans Berger in 1929, so far, is still one of the most prominent and dominant technologies to observe brain activities, especially for monitoring brain responses or state changes when a high time resolution is needed. Due to its principle relying on the detection of electric potential changes on scalp, EEG data sampling can be performed from DC to several kilohertz (depending on the device specification), and provides a great benefit for temporal feature analysis. Moreover, devices for EEG measurement are easy to miniaturize for portable uses. Thus, EEG technique can release the subjects from highly constrained conditions and provide significant freedom for brain-related experiments, hence extremely enlarges its possible applications. Although, EEG also faces its own inevitable problems as every other technology has, its advantages of low cost, portability, and high time resolution makes it one of the most prospective methods for the researches under real-life conditions.

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