1. NERVE CONDUCTION STUDIES

NCS are used to test individual nerves. Peripheral nerves are organs that serve as the “wiring” carrying signals for sensation, muscle commands, and other special functions to and from the brain and spinal cord. The nerves tested travel in predictable routes through the body, well known to each examiner. Testing involves stimulating a nerve with brief, small electrical impulse to the skin surface and recording the response from a muscle or another portion of the nerve via small detection pads on the skin. The electrical stimulations range from barely perceptible to a shock comparable to a static electric shock in winter. These studies are very safe and even the maximal machine output is too small to cause injury. Most studies require only a small fraction of the maximal level. There are no lasting effects. Information on the health of each nerve including the location and type of specific nerve injury is gathered and interpreted.

Patient Experience:

Recording electrodes are applied to the muscle being examined. The nerve is then stimulated with a small electric current. You might feel a tingle or your muscles may twitch. You should wear loose clothing and avoid using any skin lotions prior to the test.

2. ELECTROMYOGRAPHY (EMG)

This is another type of testing providing complimentary information, usually following nerve conduction studies. In this test a sterile, disposable, very thin needle electrode (about the width of a straight pin (26 gauge)), Teflon coated to ease insertion is placed through the skin into a muscle. The needle is a specialized recording device with a fine internal platinum wire, analogous to an antenna that directly records the muscle’s natural electrical activity at rest and during muscle contraction. Analysis of this activity gives important information about the health of each muscle tested as well as the controlling nerves. Each examination is specially tailored to provide information about the specific clinical questions for a given patient.

Patient Experience:

A sterile needle electrode is inserted into a muscle to “listen” to the electrical activity while you contract and relax the muscle. Nothing will be injected. You will feel the poke of the needle.

EEG stands for electroencephalogram, a test used to evaluate and measure the electrical activity in the brain. EEGs use small discs called electrodes that are placed on the scalp. These electrodes pick up tiny electrical impulses in the brain and transmit them via wires to a machine that creates a graph depicting the activity.

EEGs are noninvasive and painless. Measurements of the skull are taken first to determine the optimal placement of the electrodes, then the skin in these areas may be carefully cleaned of oils to enable the electrodes to adhere better. In some cases, the electrodes may be attached to a close-fitting cap instead of directly to the scalp. Then, the electrodes are connected to the EEG machine using a series of wires. EEGs may be conducted while the patient is awake or during sleep. During the test, patients may be asked to open and close their eyes, read or perform other simple activities to measure the brain’s activity. EEGs performed on patients who are awake typically take about an hour.

EEGs are used to diagnose an array of issues related to the brain, including: Epilepsy and other seizure disorders; Brain tumors; Encephalopathy (brain dysfunction); Encephalitis (brain inflammation); Stroke; Dementia; Brain injury and Sleep disorders.