Neurology

Electroencephalography (EEG)

• EEG tests are appropriate diagnostic indicators in relation to some of the following diseases: Epilepsy 

• Non-epileptic paroxysmal disorder 

• Infantile paralysis 

• Down's syndrome 

• Pulmonary Encephalopathy 

• Neurologic lesions 

• Cerebrovascular disorders 

• Brain tumor and other intracranial spatial disorders 

• EEG examination during and after neurosurgery and stereotaxic brain surgery

Electromyelography-Nerve Conduction Velocity-Repetitive Nerve Stimulation (MG-NCV-RNS) EMG-NCV-RNS examination is a diagnostic procedure to the following diseases: 

• Inflammatory Demyelinating Neuropathy 
• Chronic Inflammatory Demyelinating Polyradiculoneuropathy 
• Myasthenia Gravis 
• Carpal Tunnel Syndrome 
• Parkinson's disease 
• Botulism
• All neuropathies, Myopathies, Radiculopathies

EMG NERVE CONDUCTION

Why EMG is advised?
How EMG is performed?
Needle Examination
The time required to take EMG?
Preparations for EMG test?
How soon will I find out the results?

EMG stands for Electromyogram which translated means electrical testing of muscles but in fact has come to mean electrical testing of nerves and muscles. EMG is an in-office procedure and does not require hospitalization. On average, an EMG takes anywhere between 30 minutes to 2 hours.

It can be done at any time during the day and, with few exceptions, does not require any special preparation.

Why EMG is advised?
EMG is usually advised when patients are having problems with their muscles or nerves. They test the nerves and muscles of the body’s extremities, looking for a problem in either one of these areas. If you have tingling or numbness in your arms or legs, an EMG may show if you have a nerve entrapment somewhere or a nerve injury. Weakness of the muscles or “fatigue” (tiredness) may be indicative of nerve or muscle disease and require an EMG. There are many other medical problems that might suggest the need for an EMG.

How EMG is performed?

During this test, you are made to lie on an examination table, next to an EMG machine. The test consists of two parts, though at times one may be done without the other. The first part is called Nerve Conduction Studies. In this part some brief electrical shocks are delivered to your arm or leg in an effort to determine how fast or slowly your nerves are conducting the electrical current and therefore in what state of health or disease they may be. You see, a nerve works something like an electrical wire. If you want to see if the wire is functioning properly, the easiest thing to do is to run electricity through it. If there are any problems along its length, you will know it by a failure of the current to go through. To do this, the doctor will attach small recording electrodes to the surface of one part of your limb, and will touch your skin at another point with a pair of electrodes delivering the shock. When this happens, you will feel a tingling sensation that may or may not be painful. Between the brief shocks you will not feel pain. As there are several nerves in each extremity which need to be tested, the procedure is repeated 3 or 4 times or more per extremity studied. The amount of current delivered is always kept at a safe level. Patients wearing pacemakers or other electrical devices need not worry since this current will rarely interfere with such devices.

Needle Examination

The second part of the test is called Needle Examination and as the name implies, involves some needle sticking. The needles used are thin, fine and about one and a quarter inches long. This part tests the muscle to see if there has been any damage to it as a result of the nerve problem or if the disease involves the muscle itself rather than the nerve. Usually 5 to 6 muscles are sampled in one extremity, but occasionally, if you have problems in more than one area, additional muscles may need to be studied. The needle is usually inserted in the relaxed muscle and moved inside gently in order to record the muscle activity. When this is done, you will be able to hear the sound of the muscle activity amplified by the EMG machine. The painful part of this section is when the needle is first inserted through the skin since all of the pain receptors are located in this area. Once inside the muscle, the sensation is usually perceived as discomfort or pressure rather than pain. During the needle exam, no electrical shocks 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 2 to 5 minutes though this may vary with the type of problem being investigated.

The time required to take EMG?

The nerve conduction part of the test usually takes longer than the needle exam because one needs to make calculations and measurements during it. On average, if one extremity is studied, the nerve conductions take anywhere between 15 and 30 minutes. The needle exam for one extremity usually takes 15 to 20 minutes. You can count on being in the examination room for about one hour if only one extremity is requested; longer if more extremities need to be tested.

Preparations for EMG test?

Few preparations are needed on the day you have an EMG. You do not need to fast, or eat any particular kinds of food before the test. You can count on resuming your regular activity after the test is completed. As for clothing, it is not as much what you wear as it is what you don’t wear. Since in a great majority of cases the low back and buttocks area may need to be studied or in cases of neck problems, the back of the neck and shoulder areas studied, it is best not to wear clothes which will interfere with access to these areas.

With few exceptions, you may continue taking medication prescribed by your physician as ordered without this interfering with the EMG. However, if you are taking a blood thinner, you should notify the Lab where your EMG is being done, since in that case the needle part of the test may cause bleeding inside the muscle. Also if you are on any medication for Myasthenia Gravis such as Mestinon or other, your medication may interfere with the test, so you should also notify the Lab. If you have any doubts about other medications you are taking, it is best to check with the Lab to be on the safe side.

How soon will I find out the results?

Though the physician performing the test has a general idea of what the findings are during the test, the full results are only arrived at after more calculations and measurements are performed after the end of the test. The results are therefore usually not ready until later that day or even the next in complicated cases. They are usually not released directly to the patient. Instead they will be conveyed to the referring physician since he or she has to assess the results in light of the patient’s other findings.