EEG

Understanding EEG: A Window into the Brain’s Electrical Activity

Electroencephalography (EEG) is a non-invasive, powerful tool used to measure and record the electrical activity of the brain. Whether you’re a healthcare professional, a student of neuroscience, or simply someone interested in understanding the workings of the human brain, EEG offers fascinating insights into our neural activities.

What is EEG?

EEG stands for electroencephalography. It involves placing electrodes on the scalp to detect electrical impulses produced by the brain's neurons. These impulses are then amplified and recorded by the EEG machine, providing a visual representation of brain wave patterns.

History of EEG

The origins of EEG can be traced back to the early 20th century when Hans Berger, a German psychiatrist, first recorded electrical activity from a human brain. His pioneering work laid the foundation for modern neurophysiology and opened new avenues for understanding brain function and diagnosing neurological conditions.

How Does EEG Work?

EEG works by detecting the small electrical changes resulting from the brain's neuronal activity. Here’s a simplified breakdown of the process:

1. Placement of Electrodes: Small metal discs (electrodes) are attached to the scalp using a conductive gel. These electrodes are strategically placed according to the International 10-20 system, which ensures standardized positioning.
2. Recording Brain Waves: The electrodes pick up the electrical impulses produced by neurons. These signals are incredibly weak, so they are amplified by the EEG machine.
3. Displaying Results: The amplified signals are displayed on a computer screen as wavy lines, each representing the activity of a different region of the brain. The patterns and rhythms of these waves can provide valuable information about brain function.

Types of Brain Waves

EEG records different types of brain waves, each associated with various states of consciousness and brain activities:

• Delta Waves (0.5 – 4 Hz): These are the slowest brain waves, associated with deep sleep and restorative processes.
• Theta Waves (4 – 8 Hz): Common during light sleep, relaxation, and meditative states.
• Alpha Waves (8 – 13 Hz): Present during relaxed, wakeful states, often when the eyes are closed.
• Beta Waves (13 – 30 Hz): Associated with active thinking, focus, and problem-solving.
• Gamma Waves (30 – 100 Hz): Linked to high-level information processing and cognitive functioning.

Applications of EEG

EEG has a wide range of applications in both clinical and research settings:

1. Diagnosis of Neurological Disorders: EEG is crucial in diagnosing conditions like epilepsy, sleep disorders, and brain tumors. Abnormal EEG patterns can indicate areas of dysfunction.
2. Monitoring Brain Activity: In critical care units, EEG monitors brain activity in patients with head injuries or those in comas, providing real-time information on brain health.
3. Sleep Studies: EEG is a fundamental tool in sleep research, helping to identify different stages of sleep and diagnose sleep disorders like insomnia, sleep apnea, and narcolepsy.
4. Research and Cognitive Studies: EEG is used extensively in cognitive neuroscience research to study brain functions related to memory, attention, language, and more.