Neurological diagnostic procedures continue to play a pivotal role in confirming neuro-related disorders inside the human brain. With the advent of new techniques, doctors have powerful tools to detect, manage, and treat a neurological disease that helps in assessing the corresponding ailment, and its progression and test how well a particular therapy may be working.

Along with monitoring the treatment and its therapeutic effect, these new-age technologies and instruments allow science and medicine to understand the brain and its complex working patterns. Among various techniques to monitor the nervous system activity as it occurs, evoked potentials test, also called evoked response, is an essential diagnostic technique that measures the electrophysiologic responses of the nervous system to a variety of stimulants. In this process, electrical signals are generated to the brain by hearing, touch, or sight to test the efficiency of sight and hearing. A low-intensity procedure evoked potential testing that poses little to no risk to the person beyond minor discomfort at the time of testing.

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Child undergoing evoked potentials testing

Purpose Of Evoked Potentials Testing

While a few decades ago, the only way to make a definite diagnosis for many neurological disorders was to perform an autopsy after someone had passed away, presently these tests can be performed on a living human being at a testing facility safely and conveniently. In some cases, more than one sitting may be required to determine the cause of these abnormalities, and sometimes results may be immediate. Evoked potential testing is very helpful in infants and young children to find out about neurological conditions such as spinal cord injury, tumors of the acoustic nerve, stroke, injuries, abnormal brain development, hemorrhage in the brain, and multiple sclerosis. Apart from testing chronic diseases, this test is also used to monitor brain activity among coma patients in cases when confirmation of brain death is required by the physician.

Types Of Evoked Potentials

Broadly, evoked potentials can be divided into the following three categories:

Auditory Evoked Potentials

The process is also called brain stem auditory evoked response when through detecting acoustic neuromas, hearing loss and damage to the acoustic nerve and auditory pathways in the brainstem can be analyzed. The patient is made to sit in a soundproof room with headphones. The sound is delivered one at a time to one ear and then a masking sound is sent to the other ear. The entire procedure takes about an hour. Each ear is usually tested two times.

Visual Evoked Potentials

This detection is done to detect loss of vision from optic nerve damage. In this test, the person sits close to a screen and is asked to focus on the center of a shifting checkerboard pattern. One eye is tested at a time. The entire testing takes about forty to fifty minutes. This testing is potentially used to detect multiple sclerosis.

Somatosensory Evoked Potentials

Also called SSEP, it is used to measure responses from electrical stimuli to the nerves, electrodes are pasted to the arms, leg, and to the back side of the scalp to measure the signal. Tiny electrical shocks are delivered by electrodes pasted to the skin over a nerve in an arm or the leg traveling from the peripheral nerves to the brain. SSEP may be used to help diagnose multiple sclerosis, spinal cord compression or injury, and certain metabolic or degenerative disc disease. SSEP tests usually take longer than an hour.

Posterior Tibial Nerve Sensory Evoked Potentials

Also called PTNSEP, the test requires stimulation of your posterior tibial nerve located near the ankle. The tibial nerve is a branch of the sciatic nerve and a part of the lumbosacral region- the area that connects the spine to the pelvis. This test requires the application of electrodes on the scalp, hips, back, knees, and inner ankles. This exam may take up to 2 hours to complete.

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Benefits Of Evoked Potentials Test

An efficient way to monitor changes in a patient’s neurological status, evoked potentials are considered extremely effective because they can indicate problems along nerve pathways that otherwise may be diminutive or invisible during a neuro testing and may not show in an MRI at all. The evoked responses are easily quantified by measuring peak amplitudes and latencies in milliseconds, and they provide data that is a quantitative value of the neurological testing Evoked Potentials are objective, often more sensitive than any detailed neurological examination, and can be easily recorded in patients who are under anesthesia or coma. Information provided by these tests is co-related from clinical history, physical examination, and MRI scans when diagnosing the exact neurological medical condition and deciding on the further course of treatment.