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Electroencephalography (EEG)

Electroencephalography (EEG): Understanding the Procedure and Its Uses

Electroencephalography (EEG) is a neurophysiological technique used to record the brain’s spontaneous electrical activity156. During the procedure, small metal discs with thin wires, known as electrodes, are placed on the scalp to detect and record tiny electrical charges resulting from the activity of brain cells34. The EEG is typically non-invasive, and the electrodes are positioned using the International 10-20 system or its variations1. The electrical activity is amplified and displayed as a graph on a computer screen or printed on paper, which is then interpreted by a healthcare provider4.

How EEG Works

1. Detection of Electrical Activity: EEG electrodes detect voltage fluctuations from ionic current within the neurons of the brain18. The EEG signal primarily reflects the activity of cortical neurons near the electrodes1.
2. Waveform Analysis: A healthy EEG shows specific patterns of activity that correlate with a person’s level of wakefulness1. The frequencies observed typically range from 1 to 30 Hz, with amplitudes varying between 20 and 100 μV1.
3. Frequency Bands: The EEG signal is divided into frequency bands, including alpha (8–13 Hz), beta (13–30 Hz), delta (0.5–4 Hz), and theta (4–7 Hz)1. Alpha waves are seen during relaxed wakefulness, beta waves during intense mental activity, and theta and delta waves are typically associated with sleep or brain dysfunction1.

Why EEG is Performed

EEG is used to detect abnormalities in brain activity that can help diagnose various brain conditions34:

• Epilepsy and Seizure Disorders: EEG is a primary tool for diagnosing epilepsy and other seizure conditions3. It can detect abnormal electrical discharges, such as sharp waves, spikes, or spike-and-wave complexes1.
• Sleep Disorders: EEG is used to diagnose sleep disorders13.
• Brain Tumors and Stroke: EEG can be used to diagnose brain tumors and stroke3.
• Brain Death Confirmation: EEG may be used to confirm brain death in individuals in a coma3.
• Encephalopathy: EEG can help diagnose brain diseases with varied causes3.
• Head Injuries and Brain Damage: EEG can find brain damage from a head injury3.
• Brain Inflammation: EEG can help diagnose brain inflammation3.
• Monitoring Anesthesia: Continuous EEG can help find the right level of anesthesia for someone in a medically induced coma3.

EEG Procedure

During an EEG, a technician applies electrodes to the scalp using a conductive gel34. The electrodes are connected to an EEG machine, which amplifies the electrical signals and records them4. The procedure typically involves looking at about 100 pages or computer screens of activity4. The healthcare provider pays special attention to the basic waveform, brief bursts of energy, and responses to stimuli, such as flashing lights4.

Conclusion

EEG is a valuable tool for both research and clinical diagnosis of brain disorders due to its high temporal resolution and non-invasive nature12. It helps in understanding brain activity and diagnosing various neurological conditions34.

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At DrStemCellsThailand (DRSCT)‘s Anti-Aging and Regenerative Medicine Center of Thailand, we emphasize comprehensive evaluations and personalized treatment plans of Cellular Therapy and Stem Cells for managing various health conditions. If you have questions about Electroencephalography (EEG) or would like more information on our services related to neurological health, consult with our experts today!

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References:

• Electroencephalography: basic biophysical and technological aspects: This review summarizes essential aspects related to the biophysical phenomena of EEG signal generation and the technical features a clinician needs to understand in order to read and interpret EEGs. DOI: https://doi.org/10.1684/epd.2020.1217
• Electroencephalography: This article discusses EEG as a non-invasive measurement of the brain’s electric fields using electrodes placed on the scalp to record voltage potentials. DOI not available. Visit: https://pubmed.ncbi.nlm.nih.gov/30721678/