Electromyography (EMG) and nerve conduction studies (NCS) are tests that measure muscle and nerve function. In most cases, both tests are performed. NCS is most often done first. During NCS, mild electrical currents are applied to the skin on some parts of your body. This is done to see how quickly impulses travel between nerves. EMG assesses muscle function. To do this, a fine needle is placed under your skin into the muscle being tested. This is repeated on other muscles. The needle allows the electrical activity in your muscles to be measured. No electrical currents are applied with the needle. During each test, wavy lines (waveforms) appear on a screen or on paper. These lines show how well your nerves and muscles work. These waveforms help to determine your test results.
An EEG records the electrical activity of the brain. Highly sensitive monitoring equipment records the activity through electrodes that are places at measured intervals on a patient’s scalp. For the patient, the test is not painful. The head is measured and the electrodes are placed on the scalp with a paste-like substance or an Electro-Cap™ may be used. The test itself usually takes about 60 minutes, and the principal role of the patient is simply to remain still, relaxed and comfortable. During the test, the patient may be asked to take repeated deep breaths (hyperventilate) and may be shown a strobe light that flashes at different speeds. Both activities can help reveal different brain patterns that are useful for diagnosis. Sometimes, physicians also want to preserve brain patterns that occur during sleep. For sleep tests, the patient may be asked to stay awake most of the night prior to the EEG appointment. EEGs assist physicians in the diagnosis of a variety of neurological problems, from common headaches and dizziness to seizure disorders, strokes, and degenerative brain disease. The EEG is also used to look for organic causes of psychiatric symptoms and disabilities in children, and can assist physicians in determining irreversible brain death.
Evoked Potential (EP)
The EP is a recording of electrical activity from the brain, spinal nerves or sensory receptors in response to specific external stimulation. Electrodes are applied to the scalp and other areas of the body, a series of stimuli is introduced, and a computer records the neurological responses. Hundreds of responses are received, amplified and averaged by a computer. The final response is plotted on a graph and interpreted by a physician who looks for particular waveforms and the time it takes them to occur.Evoked potentials are helpful in evaluating a number of different neurological problems, including spinal cord injuries, acoustic neuroma and optic neuritis, and each type of EP looks at a different neurological pathway. The three most common types are the brainstem auditory evoked potential (BAEP), the visual evoked potential (VEP), and the somatosensory evoked potential (SSEP).
Auditory: The BAEP assists in evaluating the auditory nerve pathways from the ears through the brainstem. Electrodes are attached to the scalp and ear lobe, and earphones are placed over the ears. The phones deliver a series of clicks or tones to each ear separately.
Visual: VEPs evaluate the visual nervous system from the eyes to the occipital (visual) cortex of the brain. Electrodes are applied to the scalp, and the patient is usually asked to stare at a pattern on a video screen while remaining fully alert. Each eye is tested separately.
Botox injections for dystonia, blepharospasm, hemifacial spasm, spasticity and Chronic migraine headaches are provided under EMG guidance at our facilities.
Deep Brain Stimulation Service (DBS) Neurological Associates of St. Paul offers Deep Brain Stimulation services in collaboration with our Neurosurgery colleagues. Deep Brain Stimulation Therapy uses electrical stimulation to safely and effectively treat some of the most disabling motor symptoms of Parkinson's disease. As a result, many patients achieve greater control over their body movements and get a second chance at life. Now approved for advanced Parkinson's disease, Activa Parkinson's Control Therapy is a safe and effective adjunctive treatment option for many Parkinson's patients. Activa Therapy controls rigidity, bradykinesia/akinesia and/or tremor — while reducing the duration of dyskinesia related to antiparkinsonian medication. To make an appointment with Dr Laura Li, call our office 651-221-9051.
Canalith Repositioning for Benign Positional Paroxysmal Vertigo.
Lumbar Puncture (Spinal Tap)
A lumbar puncture (LP) is the insertion of a needle into the fluid within the spinal canal. It is termed a "lumbar puncture" because the needle goes into the lumbar portion (the "small") of the back. Other names for a lumbar puncture include spinal tap, spinal puncture or thecal puncture. A LP is most commonly performed to diagnose a disease, namely to obtain a sample of the fluid in the spinal canal (the cerebrospinal fluid) for examination.