Neuroscience Screening

Electroencephalogram (EEG) measures and records the electrical activity of your brain and translates that activity into a series of wavy lines. Conditions such as seizures often will show changes in this electrical activity. The EEG test will likely be ordered to see whether there are any ongoing irregularities in the brain’s electrical activity that may be producing seizures.

Normal electrical activity in the brain makes a recognizable pattern. Seizures produce very specific, abnormal patterns. Even without having a seizure, doctors can recognize abnormal patterns that are markers for the risk of seizures.

Having an EEG is a painless, safe procedure.

Sometimes, you’ll need to stay up late the night before and avoid caffeine on the morning of the test. 

Before the test, the EEG technologist applies small metal disks called electrodes to several places on your scalp. A special glue or paste that washes off afterwards attaches the electrode disks. Sometimes a cap with the wires already attached is used instead.

Some EEG tests are done when you’re sitting in a chair; others are performed when you’re lying down on a couch.

During the test, the technologist may ask you to breathe deeply through the mouth for a short time, which may produce a slightly dizzy feeling or numbness in your hands or feet. This sensation will go away once your breathing returns to normal. The technologist may shine a flashing light into your eyes or ask you to open and close them rapidly a few times. You may be asked to sleep or to make other simple responses, depending on the aims of the test

The average EEG test may last 35 to 40 minutes. An EEG involving a period of sleep will take longer.  

Electromyography (EMG) are tests used to measure muscle and nerve function. They are diagnostic tests used to identify the cause of pain, numbness, tingling, weakness or atrophy (shrinking muscles). EMGs are used to help diagnose conditions such as neuropathy (nerve damage), carpal tunnel syndrome (compressed wrist nerve) and sciatica (a pinched nerve). 

EMGs are in-office procedures and do not require hospitalization. On average, an EMG takes anywhere between 30 minutes and two hours, depending on how extensive a test the doctor orders. It can be done at any time during the day. 

There is no need to fast or eat any particular kinds of food before the test. You can drive yourself to and from the test. With few exceptions, patients may continue taking prescribed medication. But always notify your care provider and technician of any medications you are taking, because some can interfere with your test.  

During the EMG test, you will lie on an examination table next to the EMG machine, which looks like a desktop or laptop computer. The test consists of two parts. The first part is called nerve conduction studies [link to: new tab on Nerve Conduction Studies]. When this happens, you’ll feel a tingling sensation. The procedure is repeated three or four times or more per body part studied.  

The second part of the test is called needle examination. The needles used are thin, fine and about one and a quarter inch long. They test the muscle to see if there has been any damage to it as a result of the nerve problem. They can also help determine if your condition involves your muscle rather than nerves. Usually, five or six muscles are sampled in one area. 

The needle is usually inserted in the relaxed muscle and moved inside gently in order to record the muscle activity. During the needle exam, no electrical pulses are delivered. Also, since the needle probe is used here only as a recording device, no injections are given through the needle into the muscle. On the average, a muscle can be sampled in two to five minutes. 

Usually, you won’t receive sedation before getting an EMG. Most patients want to return to work or other regular activities immediately after the test is completed. Another reason for not giving sedation is that sedated patients need someone drive them home from the hospital, which can be difficult to arrange sometimes. Using our standard no-medication procedure, you’ll be able to drive yourself to and from your EMG test.

Nerve conduction studies (NCS) are used to evaluate the electrical conduction of nerves in your body. Examples of conditions that can be diagnosed with NCS include: 

• Neuropathy (nerve damage)
• Carpal tunnel syndrome (compressed wrist nerve)
• Radiculopathy (nerve that is pinched by your spine)

An NCS is done by providing a small electrical pulse to your nerve with a probe on your skin at one site. It records the signal at a different place along your nerve by placing electrodes on the skin. You can expect to experience a small tingling sensation, similar to the feeling when you hit your “funny bone” at the elbow. 

Several nerves in each extremity usually need to be tested, so the procedure is repeated three or four times or more per body part studied. The amount of current delivered is always kept at a safe level. No need to worry if you wear a pacemaker or other electrical device, since this current will rarely interfere with such devices. 

Evoked potentials (EP) are recordings of electrical activity from the brain, spinal nerves, or sensory receptors in response to specific external stimulation. Evoked potentials are helpful in evaluating different neurological problems including: 

• Spinal cord injuries 
• Hearing loss 
• Blurred vision and blind spots 
• Acoustic neuroma (non-cancerous tumor that affects your hearing and balance) 
• Optic neuritis (inflamed or irritated nerve that affects your eye and vision) 

Evoked potentials are performed using: 

• Earphones to stimulate the hearing pathway 
• A checkerboard pattern on a television screen to stimulate the visual pathway 
• A small electrical current to stimulate a nerve in the arm or leg