An electroencephalogram (EEG) is a diagnostic test that measures the electrical activity of the brain in order to detect and evaluate neurological conditions such as epilepsy, dementia and narcolepsy, as well to determine the rate of recovery for patients who are unconscious or in a coma.
During the EEG procedure, electrodes are placed on the head to record the electrical activity in the brain, which is interpreted by the doctor. Patients will be asked to breathe deeply, look at bright, flashing lights or go to sleep in order for the doctor to collect a range of brain activity. Brain activity is produced as a series of wavy lines that are analyzed by the doctor. This test takes one to two hours to perform, and some patients may be asked not to eat, drink or sleep for several hours before their exam.
Electromyography (EMG) is a diagnostic exam that evaluates the health of the muscles and the nerves that control them by measuring muscle electrical activity. This test is most commonly performed to determine the cause of muscle weakness and identify cases that are caused by neurologic disorders such as carpal tunnel syndrome, peripheral neuropathy and others rather than primary muscle conditions.
During the EMG exam, thin needle electrodes are inserted through the skin and into the muscle, where they detect electrical activity while the muscle is at rest and contracting. Patients may experience mild pain when the electrodes are inserted, but this is tolerable for most. This test is usually performed in conjunction with a nerve conduction velocity test.
Normal results of an EMG test indicate muscles that do not produce any electrical activity while at rest and progressively increasing with contraction. After the test, patients may experience feelings of tenderness or bruising on the affected muscle.
Evoked Potential Testing
An evoked response study is a diagnostic procedure that measures electrical activity in the brain as it responds to signals from the sight, sound and touch senses. This allows doctors to assess hearing or sight (especially useful when performed on infants), diagnose optic nerve disorders or detect tumors within the brain or spinal cord.
There are several different types of evoked response studies available that can test for different problems, including Visual Evoked Response (VER), Brainstem Auditory Evoked Response (BAER) and Somatosensory Evoked Response (SSER).
Nerve Conduction Velocity Studies (NCV)
Nerve conduction studies are utilized to determine if the patient is suffering from nerve damage or inherent deficiency. This allows the doctor to either rule out or confirm a diagnosis of nervous system issues, instead of musculoskeletal problems that could cause similar symptoms. They can also help determine the source of nerve damage, such as substance abuse, nerve compression or another peripheral neuropathy, as the specific cause can be vital to effective treatment.
Nerve conduction studies are often performed in conjunction with electromyography, which helps to diagnose muscle disease and neuromuscular conditions such as myasthenia gravis and Lou Gehrig’s disease (amyotrophic lateral sclerosis).
We provide a full range of neuroimaging services at Neurological Specialties of Long Island, PLLC, including:
- Magnetic Resonance Imaging (MRI): Utilizing our on-site American College of Radiology (ACR) accredited MRI, our neurologists can accurately diagnose brain and spinal disorders. An MRI is a safe, non-invasive test which uses a strong magnetic field to provide high resolution pictures of structures deep inside the body.
- Magnetic Resonance Angiography (MRA): This test uses the same MRI machine, but studies the blood vessels in the brain rather than the brain itself. The MRA is useful for studies of blocked arteries and aneurysms.
- Transcranial Doppler Studies (TCD) / Carotid Doppler (CD): We are an Accredited Vascular Laboratory by The Intersocietal Commission for the Accreditation of Vascular Laboratories (ICAVL). These tests are a non-invasive method of looking at the blood vessels of the head and neck using ultrasound.
Video Nystagmography (VNG)
Videonystagmography is used to determine if inner ear functions are the cause of dizziness and balance disorders. VNG is a series of tests that examine the involuntary movement of the eyes known as nystagmus. The movements are recorded through infrared cameras in the form of goggles placed over the eyes. The only discomfort from this comprehensive exam comes as a result of wearing goggles. VNG is one of the only tests that can determine if the problem is unilateral (one ear) or bilateral (both ears).