Electroencephalography (EEG) and the Devices Used to Measure It

Electroencephalography (EEG) and the Devices Used to Measure It

04/03/2022 14:15 | Technology

Every machine requires circuitry or a motherboard to control its functions and operation. Similarly, humans have a complex computing system within their bodies, known as the brain. The inner workings and connections of the brain are a mystery. It is a complex network of neurons linked together to form the brain's entire jelly-like morphology.

Medical science and inventions have improved our understanding of how the brain functions. Electroencephalography, a method and device for recording and analysing electrical activity in the brain, was one such invention.

While the first EEG was performed in 1924, technology has evolved to the point where modern portable EEG devices are changing the way we look at the brain.

This article will teach you the fundamentals of electroencephalography, its procedure, and the various devices used.

What exactly is electroencephalography (EEG)?

Electroencephalography1, also known as EEG, is a technique for recording the electrical activity of the brain in the form of waves. One can monitor the neurophysiological function of the brain while the subject is performing different tasks. Various electrical anomalies can also be precisely detected.

As we gain a better understanding of the brain, our EEG technology and the way we interpret brain signals improve. This has resulted in new methods of performing EEGs, such as wireless EEG systems, which allow us to continue learning about the brain's secrets.

The Fundamentals of EEG Functionality

The human brain is made up of billions of interconnected neurons. These neurons function by generating electrical potentials that travel through the brain as neuronal impulses. EEG works on the principle of measuring these electrical potentials/voltages generated inside the brain. The EEG machine accomplishes this by measuring voltage differences between various points with a pair of electrodes, and the resulting data is sent to an amplifier. The amplified data is eventually digitised and displayed on the monitor as a time-varying sequence of voltage values. The resulting EEG waveforms are analysed to look for signs of abnormality within the brain. An EEG Machine is made up of two parts.

An EEG machine is essentially made up of the following primary device(s):

Electrodes: Electrodes are used to detect the small electrical brainwaves produced by neurons. These are applied to the scalp with a special paste. Modern EEG machines come with a wearable cap that contains electrodes.
Amplifiers: As the signals from the electrodes travel through the machine, they pass through an amplifier, which boosts or amplifies the incoming signal sufficiently to be displayed on the screen.
Computer Control Module: A computer processes the amplified signals.
Display Device: The processed signals are displayed on the screen for the operator to analyse. Before digital monitoring methods became common, waveforms were plotted on rolls of graph paper with a moving pen.

What is the procedure for EEG?

An EEG test can be performed as an outpatient study or as part of your hospital stay. Depending on your health, you can use a variety of techniques when performing EEG. In general, an EEG procedure is carried out as follows:

  • The patient is instructed to unwind by lying down on a bed or sitting in a chair.
  • Various electrodes (between 16 and 20 or more) are applied to the scalp with a special electrolyte paste, or the patient is fitted with an electrode-containing cap.
  • The patient is then instructed to close his or her eyes and remain still.
  • This procedure is typically performed by an EEG technologist and can take anywhere from 20 minutes to 2 hours, not including electrode preparation.
  • Longer brain monitoring necessitates the patient's hospitalisation.

In recent years, modern technology has made this process easier, and portable EEG devices now offer maximum convenience without sacrificing quality results. This reduces prep time for the EEG operator (it's simple to put on and adjust, and there's no messy glue or wires to clean up), and it provides maximum comfort for the patient (the soft support pads are gentle on the skin).

These devices, also known as rapid EEGs, make EEG technology market much more accessible, allowing more people to benefit from it. The portable EEG device transmits data to the Zeto app, allowing practitioners to access real-time results from anywhere.

We're still working hard to understand the human brain, and many mysteries remain, but each technological advancement brings us closer. Portable EEG devices make it easier to study the brain, which benefits researchers, practitioners, and patients.

Brainwave Types Measured by an EEG Machine

The brain's electrical signals are displayed on the screen as waves with varying amplitude, phase, and frequency. The Fast Fourier Transform (FFT) and other signal processing techniques convert incoming signals into useful information that can be used to aid in diagnosis. Infra-low, Delta, Theta, Alpha, Beta, and Gamma are the four main types of brainwaves based on frequency.

Each brainwave corresponds to a specific function of the brain. As a result, the paragraphs that follow discuss the various important functions of the brain in relation to brain waves.

Delta Waves (frequency ranging from 0.5 Hz to 3 Hz)

Delta waves are brainwaves that are slow but loud (like the deeply penetrating waves of a drum beat). They are produced during REM sleep. When delta waves are punctuated by sleep spindles and sharp waves. When delta waves synchronise between distant cortical areas, they frequently produce sharp waves that are thought to be important for memory consolidation.

Theta Waves (frequency ranging from 3 Hz to 7 Hz)

Theta waves are most common during REM sleep. They are derived from deep subcortical sources and thus go mostly undetected by EEG. Pathological theta is the most common type of theta. Normal theta waves are known to play a role in learning and memory. We have vivid images and intuitions in our dreams when we are in theta state.

Alpha Waves (frequency ranging from 7 Hz to 13 Hz):

When a person is relaxed, lucid, or calm, alpha waves occur. These are mostly found in the brain's occipital and posterior regions. When asked to close his or her eyes and then relax, the brain is disengaged from any complex cognitive tasks or thinking, and alpha waves are induced.

Beta waves: (frequency ranging from 14 Hz to about 38 Hz:

The term "beta waves" refers to a state of mind that is alert, attentive, and conscious. These have a low amplitude and are linked to motor decisions. Beta waves are further classified as follows:

  • While musing, low-beta waves (Beta1, 12-15 Hz) occur.
  • Mid-Beta Waves (Beta2, 15-22 Hz): occur when you are deeply engaged in something or actively attempting to figure something out.
  • High-Beta Waves (Beta3, 22-38 Hz): These occur during complex thought processes and the integration of new experiences. Also associated with extreme anxiety or excitement. 9

Gamma Rays (frequency ranging from 38 Hz to 120 Hz)

These are the quickest brainwaves, with the highest frequency and the smallest amplitude. They are frequently contaminated by electric noise or muscle artefacts due to their small amplitude and high frequency. EEG captures gamma waves, which provide information about information processing in the brain 10. The synchrony of gamma waves between different parts of the brain reflects the exchange of information between those areas. Gamma waves are still a mystery because they orchestrate the synchronised activity of neurons.

  • Low-Gamma Waves (38-60 Hz): Cognitive tasks and active attentive behaviour
  • High-Gamma (60-120 Hz) Waves: Their function is unclear, but their predominance is considered diagnostic of epilepsy.

EEG Use and Applications

EEG is now used to diagnose and treat brain-related disorders.

  • The most powerful and preferred diagnostic procedure for epilepsy is electroencephalography (EEG).
  • 13 EEG is extremely useful in diagnosing sleep disorders such as insomnia, parasomnias, and so on.
  • EEG has valuable diagnostic potential for a variety of other neurological conditions, including stroke, autism, depression, and ADHD, to name a few.
  • EEG is emerging as the tool of choice for next-generation Brain Computer Interfaces and Neural Prosthetics.
  • EEG can be used to track attention during a variety of activities, assisting in the development of stress-reduction and focus-improvement strategies.
  • To help objectively identify participants' responses, EEG has been introduced as a new tool for Neuromarketing studies.

And the list continues to grow...

In conclusion

The development of EEG opened up a new avenue for learning about the brain. EEG has proven to be invaluable in the treatment of seizures, epilepsy, and sleep disorders, and it has great potential in the treatment of other neurological issues. A greater good can be achieved as EEG becomes simpler, easier to acquire and interpret, and wireless. It's just a matter of when, given recent advances in electronics, cloud computing, and machine learning. EEG has a promising future. As a result, advances in our understanding of the brain could not be more exciting. Learn more about the differences between wet and dry EEG tests.