EEG Definition
EEG stands for “electroencephalography” which is an electrophysiological process to record the electrical activity of the brain. EEG measures changes in the electrical activity produced by the brain. Voltage changes come from ionic current within and between some brain cells called neurons.
What is EEG Used For?
Performance and Wellness
Athletes, biohackers, and any interested consumer can use EEG to track their brain activity the same way they might track the number of steps they take in a day. EEG can measure cognitive functions — such as attention and distraction, stress and cognitive load (the brain’s total capacity for mental activity imposed on working memory at any moment). These findings can reveal valuable insights into how the brain responds to daily life events. EEG data provides feedback that can be used to design scientifically informed strategies to reduce stress, improve focus or enhance meditation.
Consumer Research
EEG data can be a powerful tool for consumer insights. Brain responses provide unprecedented consumer feedback — in that EEG is being used to measure the gap between what consumers really pay attention to versus what they self-report liking or noticing. Combining EEG with other biometric sensors like eye-tracking, facial expression analysis, and heart rate measurements can provide a complete understanding of customer behavior to the companies. The use of neurotechnologies like EEG to study consumer reactions is called neuromarketing.
Healthcare
Because EEG tests show brain activity during a controlled procedure, results can contain information used to diagnose various brain disorders. Abnormal EEG data is displayed through irregular brainwaves. Abnormal EEG data can indicate signs of brain dysfunction, head trauma, sleep disorders, memory problems, brain tumors, stroke, dementia, seizure disorders like epilepsy and various other conditions. Depending on the intended diagnosis, doctors sometimes combine EEG with cognitive tests, brain activity monitoring and neuroimaging techniques.
Seizure Diagnosis
EEG tests are often recommended to patients experiencing the seizure activity. In these cases, doctors may conduct an ambulatory EEG. An ambulatory EEG records continuously for up to 72 hours, while traditional EEG lasts for 1–2 hours. The patient is allowed to move around in their own home wearing an EEG headset. Extending the recording increases the likelihood of recording abnormal brain activity. For that reason, ambulatory EEGs are often used to diagnose epilepsy, seizure disorders, or sleep disorders.
Sleep Study for Sleep Disorders
An EEG sleep study or “polysomnography” test measures body activity in addition to performing a brain scan. An EEG technologist monitors heart rate, breathing and oxygen levels in your blood during an overnight procedure. Polysomnography is mostly used in medical research and as a diagnostic test for sleep disorders.
Quantitative Neuroscience
Since EEG measures electrical activity in the outer layer of the brain (the cerebral cortex), it can pick up brainwaves from your scalp. By combining EEG brain tests with data from other brain monitoring techniques, researchers can gain new insights into the complex interactions taking place in our brains — as well as in our bodies.
That’s exactly what quantitative electroencephalography (qEEG) aims to accomplish. Quantitative EEG records your brainwaves just like a traditional EEG. Using machine learning, qEEG compares your brainwaves with the brainwaves of individuals in the same gender and age range, but for those who do not have brain dysfunction. The qEEG process creates a “map” of your brain through the quantitative comparison. This process is common in the sub-discipline of neuroscience called computational neuroscience.
EEG electrode placement is a critical part of successful qEEG. Traditional EEG lead placements follow the 10–20 system, an internationally recognized standard for applying the electrodes attached to your scalp. “10–20” refers to the distance between EEG leads being 10% or 20% of the total distance of the skull.
The number of electrodes on a device can vary — some EEG recording systems can have as many 256 electrodes. Recordings of qEEG use a 19-sensor cap to gather data from all 19 areas of your scalp. Because EEG leads amplify signals from the site they’re placed, acquiring qEEG brain mappings identify at the brain level the cause of dysfunction observed at the behavioral and/or cognitive level.
Academic Research
Abnormal EEG results aren’t the only valuable information derived from an EEG test result. Many researchers use normal EEG in their research, including a groundbreaking 1957 study on brain activity during REM sleep.
As introduced in the section on the types of brainwaves that EEG measures, studying EEG recordings reveal a range of frequencies contained within brain signals. These frequencies reflect different attentional and cognitive states. For example, researchers have monitored gamma-band activity (often associated with conscious attention) while investigating the neurological responses during meditation (EEG meditation).
Gamma band activity is associated with peak mental or physical performance. Experiments where a subject wearing an EEG device is practicing deep meditation brought on theories that gamma waves are associated with conscious experiences or transcendental mental states. However, there is no agreement among academic researchers around what cognitive functions that gamma-band activity is associated with.
Researchers need a way to process and handle all the wealth of brain data they collect — and even share it with different institutions. “Neuroinformatics” is the field of research that provides computational tools and mathematical models for neuroscience data. Neuroinformatics aims to create technologies for organizing databases, data sharing, and data modeling. It entails a diverse amount of data, as “neuroscience” is broadly defined as the scientific study of the nervous system. One of the neuroscience’s sub-disciplines includes cognitive psychology, which uses neuroimaging methods such as EEG to analyze which parts of the brain and nervous system underlie which cognitive processes.
Market Research: Using EEG Headsets to Understand Emotional & Cognitive State
EEG Games
EMOTIV’s EPOC X headset is the first high-fidelity brain-computer interface (BCI) that can monitor and interpret conscious and unconscious thoughts and emotions. The BCI can detect the complex brainwaves of 30 different expressions, emotions and actions. This detection is achieved through machine learning. Machine learning algorithms have been trained to recognize the brain patterns that occur while the participant processes the various expressions, emotions, and actions.
When the algorithms pick up on an EEG brainwave in its data set, the BCI can associate the pattern with a physical or digital command. For example, thinking a trigger word like “push!” will make your avatar push an object out of their path.
TechCrunch TV: Mind Controlled Devices and More Using EEG
Advantages of EEG
There are many alternative methods to study brain function including:
- Functional magnetic resonance imaging (fMRI)
- Magnetoencephalography (MEG)
- Nuclear magnetic resonance spectroscopy (NMR or MRS)
- Positron emission tomography (PET)
However, EEG measurement is the least invasive measure of brain activity we have available, and provides lots of quantitative information during relevant cognitive processes. Other advantages include:
- EEG has a very high temporal resolution compared to Functional magnetic resonance imaging (fMRI). It can pick up the rapid reactions of the brain that happen at the speed of milliseconds, which allows it to sync accurately what happens in the brain and in the environment. EEG is recorded at sampling rates between 250 and 2000 Hz in clinical and research settings. More modern EEG data collection systems can record at sampling rates above 20,000 Hz if desired.
- Significantly lower hardware costs and total cost of ownership (TCO).
- EEG data is collected non-invasively unlike electrocorticography, which requires neurosurgery for electrodes to be placed directly on the surface of the brain.
- Mobile EEG sensors can be used in more places than fMRI, SPECT, PET, MRS, or MEG, as these techniques rely on heavy, costly and immobile equipment.
- EEG is silent, to allow for studying the responses to auditory stimuli.
- Compared to fMRI and MRI, there is no physical danger around an EEG machine. fMRI and MRI are powerful magnets that prevent use by patients with metallic gear such as pacemakers.
- fMRI, PET, MRS, and SPECT can aggravate claustrophobia which can corrupt test results. EEG does not induce claustrophobia as subjects are not confined to a small space.
- Consumer EEG scans allow for more subject movement during testing, unlike most other neuroimaging techniques.
- EEG does not involve exposure to radioligands, unlike positron emission tomography, or high-level magnetic fields like MRI or fMRI.
- EEG does not involve exposure to high-intensity (>1 tesla) magnetic fields.
- Compared to behavioral testing methods, EEG can detect covert processing (processing that does not require a response). This technology also is used in subjects who are unable to make a motor response.
- EEG has a low barrier of entry for consumer use so it is a powerful tool for tracking and recording brain activity during different activities of daily life, allowing for a nearly limitless number of applications.
- EEG sleep analysis can indicate significant aspects of the timing of brain development, including evaluating adolescent brain maturation.
- There is a better understanding of exactly what signal is measured with EEG, compared to the BOLD (Blood-oxygen-level-dependent) imaging used in fMRI.
New EEG Use Cases
We are only just beginning to scratch the surface of how EEG can be used. There are many modern applications for EEG measurement. Some notable and novel use cases include:
- Neuromarketing
- Sleep Studies
- Brain Computer Interface (BCI)
- Self-Quantification
- ADHD Therapy
- Neurological disorders
- Brainwave entrainment
- Cognitive behavioral therapy
- Neuroinformatics
- Brainwave gaming
- AR & VR supplement
- Dysphagia and Dementia
- Stroke rehabilitation
