EEG Primer – Part 2

So what is in the EEG data?

How is the EEG data interpreted?

As the electrical activity produced by the brain is examined by the EEG equipment, we can interpret which areas of the brain are processing which information at a specific time.

  • Occipital lobe

The occipital lobe makes sense of the visual information in order for us to understand it. It is responsible for processing visual information. If this part of the brain is damaged we would not be able to process the visual signals correctly.

  • Parietal cortex

It is responsible for the processing of sensory information within seconds. If this part of the brain would be damaged, humans wouldn’t be able to feel sensations of touch.

  • Temporal cortex

Just like the occipital lobe is responsible for processing visual information, the temporal lobe is responsible for processing auditory information. It revolves around hearing and listening and understanding and interpreting the information.

  • Frontal cortex

This is where we form our personalities and become who we are. It is responsible for making decisions like what to wear or when to sleep and is also in charge for thinking and understanding something. It is essential for being able to speak fluently and meaningfully.

Apart from where the electric movement generates from we can also analyze the frequencies which make the ongoing activity. At different states, the brain generates different frequency patterns.

  • Delta(1-4 Hz)

This is primarily for examining how deep the sleep is. The stronger the delta rhythm, deeper the sleep will be.

  • Theta(4-7 Hz)

This is related with cognitive tasks like recalling memory and difficult tasks, for example what you ate 3 days back or reading the alphabet backwards.

  • Alpha (7-12 Hz)

It is associated with the state when we are relaxed but drowsy. It coordinates multi sensory processing, attention and concentration.

  • Beta (12-30 Hz)

It is related with body movements, when we anticipate or even notice body movements. These become stronger as we plan to execute any movement.

  • Gamma (30-50 Hz)

Gamma frequency is associated with attentive focusing and serves as carrier frequency to facilitate the exchange of data between different brain regions.

Analyzing the EEG (Electroencephalogram) data, can be quite challenging. Examining the data, in order to extract and indentify information requires expertise and experience.

USES OF EEG (Electroencephalogram)

Why is it performed?

An EEG is performed to check if there are any problems in the electrical activity of the brain which may be related to specific brain disorders. The values and measurements used by an EEG are used to either confirm or to take out the following conditions:

  • Dementia: it is related to symptoms like loss of memory and reduced thinking skills resulting difficulty in performing daily activities.
  • Stroke: stroke is a condition where the brain stops functioning properly due to the lack of blood flow or due to bleeding.
  • Head injury: any type of injury to the brain, skull or scalp. It could either be a mild bump of a traumatic brain injury which results to some sort of damage.
  • Seizure disorders (epilepsy): seizure refers to a sudden rush of electrical brain activity. Epilepsy is a chronic disorder with unprovoked seizures.
  • Brain tumors: tumors can either be malignant or benign. A tumor is a mass of tissue formed by the collection of abnormal cells.
  • Sleep disorders: this includes sleep apnea, narcolepsy, cataplexy and sleeping sickness.
  • Memory problems: this is related to Alzheimer in which memory is affected. The thinking, reasoning and memory skills are reduced.
  • Encephalopathy: it is a brain disease, damage or malfunction

EEG can also be performed on people that are in coma. Their brain activity can be tested in order to see if there is any progress or improvement in the individual. The test can also be done during brain surgery so that brain activity is monitored.




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