Electromyogram
Electromyography (EMG) neurophysiological testing is a dynamic laboratory method of study and investigation to assess muscle and nerve health. assess the function of the peripheral nerves, i.e. the nerves of the body outside the brain and spinal cord. This means that lesions of any kind in the spinal cord or brain do not show characteristic abnormal findings on electromyography .
The audit consists of two phases:
1. The control of nerve conduction velocities (neurophysiological control)
2. Checking muscle function (myogram).
Nerve conduction studies use surface electrodes while during myography a needle electrode is inserted directly into a muscle and records the electrical activity in that muscle. The EMG converts the signals into images, sounds and numbers that are interpreted by a neurologist.
Why is the test performed?
The test is often necessary to diagnose or rule out certain conditions such as:
- Muscle diseases, such as muscular dystrophy or polymyositis.
- Diseases that affect the connection between the nerve and the muscle, such as myasthenia gravis.
- Nerve disorders outside the central nervous system (peripheral nervous system) such as carpal tunnel syndrome or peripheral neuropathies.
- Disorders affecting the motor neurons in the brain or spinal cord (central nervous system), such as motor neurone disease or polio.
- Disorders affecting the nerve root, such as herniated discs in the spine usually in the neck or back.
In practice, the most common conditions for which EMG is performed are carpal tunnel syndrome, ulnar neuropathy, diabetic neuropathy and authenalgias.
How is the examination performed?
Electromyography is performed by inserting special thin needle-like electrodes into certain muscles selected according to the diagnostic goal or the patient’s symptoms. With these needle-like electrodes, the doctor can distinguish whether there is damage to the muscles themselves or to the nerves that supply them, as well as other data related to the time since the invasion of the damage and its severity. The muscles and nerves selected for study may be located in the limbs, trunk or head.
Examination Preparation
Before the test, you should tell the doctor if you are taking medications such as muscle relaxants or antipyretics, if you are carrying a pacemaker or stimulator for deep brain stimulation. Make sure you wear comfortable and loose clothing, keep your skin clean with no perfumes, creams or lotions. The examination is performed in the sitting or supine position, depending on whether the upper or lower limbs are examined.
The duration of the examination depends on the location and extent of the lesion and lasts from 20 to 50 minutes. There are generally no side effects from the test. Although slight discomfort may occur during the test, there are no complications afterwards. If a small bruise develops when using the needle it is soon absorbed. The test is safe for pregnant women and children.
Electroencephalogram
An electroencephalogram “EEG” is a test that measures electrical activity in the brain and records brain wave patterns. Certain brain conditions can affect a person’s brain wave patterns. Brain cells communicate with each other using electrical signals. Certain age-related disorders can affect the transmission of these signals. The electroencephalogram essentially measures changes in the electrical activity of the brain.
Why is the test performed?
The test is the best diagnostic tool for epilepsy and other seizure disorders . It is often used in conjunction with other imaging tests, such as CT and MRI, and laboratory tests to diagnose epilepsy . EEG can also help the doctor diagnose other conditions such as:
- Confusion
- Dementia
- Tinnitus of the head
- Infections
- Neoplasms
- Sleepdisorders
- Neurodegenerative diseases
- Metabolic disorders affecting brain function
At the same time, the test is indicated for those who
- Have a brain tumour or brain trauma
- They’re about to undergo brain surgery
- Have disorders with headaches
How is the examination performed?
At the beginning of the EEG the doctor will place the electrodes on the subject’s scalp, using a special gel that is removed by simple shampooing. The electrodes are connected to special wires that transfer the brain activity to a computer and record it.
After the electrodes are placed, the examinee will either lie down on an examination bed or in a chair. He/she will be asked to lie still and close his/her eyes. During the examination, the room will be quiet and dark. The doctor will ask the patient to perform various commands, such as blinking, looking at a flashing light or breathing deeply, as these behaviors cause abnormal electrical signals. Often, the doctor can record the electroencephalogram on video so that he or she can later compare the electrical signals with the patient’s reactions at that moment.
Examination Preparation
The preparation for an electroencephalogram, includes:
- Washing the scalp with shampoo. No gel or hair cream should be applied at the time of the examination
- Avoiding caffeine for at least 8 hours before
- Following the doctor ‘s instructions regarding the medication the examinee may take
The doctor may ask to limit sleep before the EEG so that the patient is sleepy during the test. An electroencephalogram during sleep or after sleep deprivation has a greater chance of detecting abnormal activity in the brain.
There are usually no side effects to performing an EEG and the procedure is completely painless. An EEG only takes information about the electrical energy produced by the brain.
The duration of the examination is 20-40 minutes, it is painless and non-invasive and does not cause permanent changes