|Mercy Medical Center Neurodiagnostic Lab
ACCREDITED EEG LAB
Mercy Medical Center Neurodiagnostic Lab is accredited by the EEG Laboratory Accreditation Board of ABRET. Mercy Medical Centers Neurodiagnostic Lab is just one of two labs accredited in the state of Massachusetts.
Diagnostic Services Offered
- Standard Electroencephalogram (EEG)
- Ambulatory Electroencephalogram (EEG)
- Electromyography (EMG) and Nerve Conduction Velocity (NCV)
- Visual Evoke Potential
- Auditory Brainstem Evoked Potential
- Somatosensory Evoked Potential
Outpatient services are provided to patients ages five and up, Monday through Thursday, 7 a.m. to 5 p.m.; Friday 7 a.m. to 3 p.m., holidays excluded.
**Written orders from a physician and/or referrals are required for all services performed by this department.
For further information on any of these tests or to schedule an appointment, call us at 413-748-9610.
What is ABRET?
ABRET is the national credentialing board for Electroencephalographic Technologists, Evoked Potential Technologists, Long Term Monitoring Technologists, and Neurophysiologic Intraoperative Monitoring Technologists. It has been focused on the competency and evaluation of technologists serving the neurology community and patients for more than 40 years. ABRET's Lab Accreditation process evaluates technical standards, the quality of the laboratory's output and lab management issues. Accreditation by ABRET with independent, objective verification of quality shows proof that the lab can produce EEGs interpretable by competent physicians anywhere; identifies the lab's status to colleagues and patients; enhances the credibility for its data; distinguishes its characteristics from the competition; and heightens the laboratory's reputation for integrity. ABRET credentials are internationally recognized and endorsed by the American Clinical Neurophysiology Society (ACNS) and the American Society of Electroneurodiagnostic Technologists (ASET).
What is Electroencephalogram (EEG)?
An electroencephalogram (EEG) is a test that measures and records the electrical activity of your brain. Special sensors (electrodes) are attached to your head and hooked by wires to a computer. The computer records your brain's electrical activity on the screen or on paper as wavy lines. Certain conditions, such as seizures, can be seen by the changes in the normal pattern of the brain's electrical activity.
Why It Is Done
An electroencephalogram (EEG) may be done to:
- Diagnose epilepsy and see what type of seizures are occurring. EEG is the most useful and important test in confirming a diagnosis of epilepsy.
- Check for problems with loss of consciousness or dementia.
- Help find out a person's chance of recovery after a change in consciousness.
- Find out if a person who is in a coma is brain-dead.
- Study sleep disorders, such as narcolepsy.
- Help find out if a person has a physical problem (problems in the brain, spinal cord, or nervous system) or a mental health problem.
How To Prepare
Before the day of the electroencephalogram (EEG) test, tell your doctor if you are taking any medicines. Your doctor may ask you to stop taking certain medicines (such as sedatives and tranquilizers, muscle relaxants, sleeping aids, or medicines used to treat seizures) before the test. These medicines can affect your brain's usual electrical activity and cause abnormal test results.
Do not eat or drink foods that have caffeine (such as coffee, tea, cola, and chocolate) for eight hours before the test.
Since the electrodes are attached to your scalp, it is important that your hair be clean and free of sprays, oils, creams, and lotions. Shampoo your hair and rinse with clear water the evening before or the morning of the test. Do not put any hair conditioner or oil on after shampooing.
To find certain types of abnormal electrical activity in the brain, you may have to be asleep during the recording. You may be asked not to sleep at all the night before the test or to sleep less (about four or five hours) by going to bed later and getting up earlier than usual. If your child is going to be tested, try to keep him or her from taking naps just before the test. If you know that you are going to have a sleep-deprived EEG.
How It Is Done
An electroencephalogram (EEG) may be done in a hospital or in a doctor's office by an EEG technologist. The EEG record is read by a doctor who is specially trained to diagnose and treat disorders affecting the nervous system (neurologist).
Electromyogram (EMG) and Nerve Conduction Studies
An electromyogram (EMG) measures the electrical activity of muscles at rest and during contraction. Nerve conduction studies measure how well and how fast the nerves can send electrical signals. Nerves control the muscles in the body by electrical signals (impulses), and these impulses make the muscles react in specific ways. Nerve and muscle disorders cause the muscles to react in abnormal ways.
Measuring the electrical activity in muscles and nerves can help find diseases that damage muscle tissue (such as muscular dystrophy) or nerves (such as amyotrophic lateral sclerosis or peripheral neuropathies). EMG and nerve conduction studies are often done together to give more complete information.
Why It Is Done
An electromyogram (EMG) is done to:
- Find diseases that damage muscle tissue, nerves, or the junctions between nerve and muscle (neuromuscular junctions). These disorders may include a herniated disc, amyotrophic lateral sclerosis (ALS), or myasthenia gravis (MG).
- Find the cause of weakness, paralysis, or muscle twitching. Problems in a muscle, the nerves supplying a muscle, the spinal cord, or the area of the brain that controls a muscle can cause these symptoms. The EMG does not show brain or spinal cord diseases.
Nerve conduction studies are done to:
How To Prepare
Tell your doctor if you:
- Are taking any medicines. Certain medicines that act on the nervous system (such as muscle relaxants and anticholinergics) can change electromyogram (EMG) results. You may need to stop taking these medicines three to six days before the test.
- Have had bleeding problems or take blood thinners, such as warfarin (Coumadin) or heparin. If you take blood thinners, your doctor will tell you when or if to stop taking them before the test.
- Have a pacemaker.
Do not smoke for three hours before the test.
Wear loose-fitting clothing so your muscles and nerves can be tested. You may be given a hospital gown to wear.
For an EMG, you may be asked to sign a consent form. Talk to your doctor about any concerns you have regarding the need for the test, its risks, how it will be done, or what the results will mean.
Evoked Potential Test for Demyelinating Disease
An evoked potential test measures the time it takes for nerves to respond to stimulation. The size of the response is also measured. Nerves from different areas of the body may be tested.
Types of responses are:
- Visual evoked response or potential (VER or VEP), which is when the eyes are stimulated by looking at a test pattern.
- Auditory brain stem evoked response or potential (ABER or ABEP), which is when hearing is stimulated by listening to a test tone.
- Somatosensory evoked response or potential (SSER or SSEP), which is when the nerves of the arms and legs are stimulated by an electrical pulse.
Each type of response is recorded from brain waves by using electrodes taped to the head. The visual evoked response (VER) is the most commonly used evoked potential test in the diagnosis of multiple sclerosis (MS).
Conducting gel and electrodes are applied to the scalp. The location will depend on the type of response being recorded. For example, when VERs are recorded, the electrodes are applied to the rear (occipital region) of the scalp over the brain areas that register visual stimuli.
Stimuli are delivered:
- For VER by a screen with a checkerboard pattern.
- For ABER by clicking noises or a tone sent through earphones.
- For SSER by an electrical pulse at the wrist or ankle. This pulse is a mild electrical shock.
Responses from the electrodes are recorded. The time between the stimulation and the response is called the latency, which indicates the speed at which the nerves pass a signal.
Why It Is Done
This test may be used when demyelinating disease such as multiple sclerosis (MS) is suspected and a neurological examination alone does not provide enough evidence.
For a clear diagnosis of MS, the doctor has to find evidence that multiple parts of the central nervous system are affected. When there are symptoms clearly caused by MS lesions of the spine but no visual symptoms, the visual response may be tested anyway. Abnormal results in such cases mean that there are also areas of damage (MS lesions) on the brain.
Findings of this test may include the following.
The time between the stimulation and the nerve's response is within the normal range.
Some people who are free from symptoms in the nerve area tested will still have abnormal responses in that area.
Abnormal response times can also be associated with other neurological diseases or with damaged optic nerves and eyes.
For more information or to schedule an appointment, call the Neurodiagnostic Lab at Mercy Medical Center at 413-748-9610.