Overview of EEG Normal Waveforms
An EEG, or electroencephalogram, is a test that track and records brain wave patterns. The data collected during an EEG represents the combined activities of millions of brain cells, all working together. This is a bit like listening to the hum of a busy city from high above. Analyzing and interpreting these results is a delicate balance of science and skill. Normal EEG results can vary widely from person to person, based on their individual body processes.
How is EEG Normal Waveforms performed
Interpreting the patterns in an EEG, a test that detects electrical activity in your brain, requires a meticulous, step-by-step approach. Before you even begin the process, you need to keep in mind several factors that can influence the test’s results. These factors include the patient’s age, whether they are awake or asleep, their physical and mental activity at the time, and the presence of any biological or environmental impacts or medications that could alter the brain’s electrical activity.
What Else Should I Know About EEG Normal Waveforms?
An EEG, or electroencephalogram, is a test that records the electrical signals in your brain. These electrical signals show up as waveforms on the EEG and can be categorized by their location, size, speed, shape, pattern, symmetry, and response to activity. Most of the time, these waveforms are grouped by their speed or frequency, hence they are named after Greek numerals. The most studied waveforms include delta (very slow), theta (slow), alpha (moderate), sigma (fast), and beta (very fast). There are also other waveforms that move even slower or faster, but these are studied less often as the equipment needed to record these waveforms is not always available.
In a normal clinical setting, an EEG focuses on waveforms that range from very slow to very, very fast. This is done by filtering out the EEG signals. A new kind of EEG, called a full bandwidth EEG, can look at all of the waveforms without directing the focus on any one frequency band over the others. Although, recording such an extensive range of frequencies is not normally done because it needs special equipment that can record data at higher speeds and will use more storage space.
Different types of waveforms can tell us different things about the brain:
1. Infra-slow oscillations (very, very slow): These are often present at the early stage of a baby’s brain development when sensory input plays little to no role. These are also seen during non-REM sleep in sync with faster EEG activities. Very slow EEG responses along with variable slow fluctuations at the seizure focus can also be seen in animal models and humans.
2. Delta (very slow): The delta rhythm naturally appears in deep sleep and is often present in the front center of the brain. When a patient is awake, it could mean generalized encephalopathy and focal cerebral dysfunction.
3. Theta (slow): The theta rhythm comes on when we become drowsy and enter the early stages of sleep. Heightened emotional states can also enhance frontal rhythmic theta rhythm in children and young adults.
4. Alpha (moderate): The posterior dominant alpha rhythm is often seen in normal awake EEG recordings and is most commonly found in the back of the brain. It is considered a sign of good brain health if one’s background alpha rhythm is fast.
5. Sigma waves: These are seen in N2 sleep and are known as sleep spindles or sigma waves.
6. Beta (fast): Beta rhythm is the most common rhythm seen in normal adults and children and are seen throughout the brain.
EEGs are commonly used to study the brain’s activity during rest and during various tasks. It is used to spot brain issues early, diagnose seizures, examine sleep disorders, and assess overall brain health.