Conditions and Treatments

Electroneuromyograhy (EMG) is a series of tests that measure how the nerves and muscles are working and how well the nerves communicate with the muscles. This testing can tell us where a nerve or muscle problem is located and often the nature of the problem based on the abnormalities discovered. EMG is most often done in the outpatient setting but can also be done in the hospital. It is performed by neuromuscular specialists who have been trained in the techniques involved and how to interpret the results.

There are two main components to the test, which usually takes 30 to 60 minutes. The first consists of nerve conduction studies, which are performed by giving shocks to the nerves and then measuring how fast the nerve conducts and how big a signal is produced a fixed distance away. The doctor or technician may use heated towels to warm your arms or legs before testing. With motor nerves, an electrode is placed on a specific muscle, and the shock to the nerve causes a small muscle twitch which is detected by the electrode. If the signal takes longer than expected to reach the muscle, there may be a problem with the myelin cells that cover and insulate the nerves, suggesting a “demyelinating neuropathy.” If the muscle twitch is smaller than expected, it could be a problem with the axon nerve fibers that make up the nerve, suggesting an “axonal neuropathy,” or it could also be a problem with the muscle itself.  With sensory nerves, the electrode picks up a tiny signal in the sensory nerve. Other tests may look at the signals that go up to the spinal cord and back down the nerve. Together, these tests show how the nerves are working. If you have weakness, the doctor may give a rapid series of shocks to the nerve which tests whether there is a problem with the chemical signals from the nerves going to the muscles. This occurs with diseases like Myasthenia gravis.

The second part of the test involves inserting small needle electrodes into specific muscles. This can be uncomfortable but most patients tolerate it well, and your doctor will monitor how you are doing at all times. This part of the test shows whether the muscles are “irritable” due to loss of nerve connections, whether the nerve has partially grown back to contact more muscle fibers, and whether there might be a problem in the muscles themselves. Your doctor may ask you to gradually move a single muscle by increasing amounts. These tests provide important information that can lead to diagnosis of a wide variety of nerve and muscle diseases, including common conditions like Carpal Tunnel Syndrome and rare conditions such as Amyotrophic Lateral Sclerosis (ALS). EMG can also be used by your neurologist to select specific muscles for botulinum toxin injections.

Autonomic disorders are conditions associated with changes in the autonomic nervous system that regulates body functions not under voluntary control. These diseases can result in changes in the control of blood pressure, sweating and bowel or bladder control, and cause episodes of loss of consciousness, bladder or bowel incontinence or constipation, and erectile dysfunction. Autonomic problems can occur in isolation or as a symptom of a neurodegenerative condition such as Parkinson’s disease or Alzheimer’s disease. Our Autonomic Lab provides a complete set of diagnostic tools that can determine the nature of the autonomic problem and help your neurologist manage your symptoms. These include a tilt table test, in which you are strapped to a table (a little like the “Bride of Frankenstein”!) and gradually tilted from horizontal up to near vertical while you blood pressure and heart rate are carefully monitored. The doctor will ask you if tilting the table produces dizziness or other symptoms. Another test examines your ability to produce sweat by chemically stimulating a patch of skin on your forearm or leg. These autonomic tests are performed in the outpatient clinic setting, and can help your neurologist understand the problem and what needs to be done to treat it.

Myasthenia gravis (MG) causes weakness that gets worse with increasing effort or activity and improves with rest. It often presents with droopy eyelids or double vision, and trouble with swallowing or talking. Generalized weakness can also occur, particularly at the end of the day.

MG most commonly occurs in women under the age of 40 and in men over the age of 60. It is due to a problem at the neuromuscular junction that prevents chemical signals from passing from the nerves to the muscles, which results in fluctuating muscle weakness. MG is caused by an autoimmune response, which occurs when the immune system targets a part of our own bodies rather than foreign bacteria or viruses. The immune system creates antibodies against the receptors on the muscles for the chemical acetylcholine, which prevents the signals from activating the muscles. These antibodies can be detected in the blood in about 90% of people who have MG with generalized weakness, and about 50% of people whose MG affects only their eyes. Electroneuromyography (EMG) can also help with the diagnosis, showing decreased muscle responses with repetitive stimulation. It is not clear what triggers the autoimmune response, but it has been associated with tumors of a gland called the thymus in the chest, as well as certain medications. Your doctor may order a CT scan of the chest to find out if you have an enlarged thymus or a thymus tumor (thymoma), and if so, an operation to remove it often improves the ability of medicines to control MG symptoms.

A number of medications have been used for long term control of MG. These often include a steroid (prednisone) or other immune-suppressing medicine like azathioprine (Imuran®), sometimes together with a medication that helps improve chemical communication between the nerves and muscles such as pyridostigmine (Mestinon®).

MG can be life threatening if it causes weakness of the respiratory muscles. You should let your neurologist know if you develop shortness of breath. If symptoms are mild, a pulmonary function test may be helpful to track your breathing. If you suddenly become severely short of breath, you should call 911 to be taken to a hospital, as symptoms can progress rapidly into an acute “myasthenic crisis” which requires admission to the hospital. Sometimes a ventilator is needed to keep you breathing while special treatments are given. These include intravenous immunoglobulin (IVIG) which downregulates the immune response to the MG antibody, or plasma exchange in which the antibodies are removed from the blood in a “blood-washing” dialysis machine, usually every other day for 5 treatments. MG crisis can sometimes occur in the setting of pregnancy, infections or medication changes.

Motor-neuron disease (MND) is a class of disorders that affect the motor neurons and results in marked muscle weakness, loss of muscle bulk (atrophy), and often tiny muscle twitches known as fasciculations. The cause of MND is not known, but it seems to selectively attack motor neurons, the nerve cells that control muscle movement, while sparing the sensory systems. There are two main types of motor neurons. The “upper motor neurons” live in an area of the brain just in front of a major groove called the central sulcus, and send their axon fibers down the spinal cord. These fibers send information to the “lower motor neurons” that directly contact the muscles. Loss of the lower motor neurons causes weakness and atrophy of the muscles and the twitches called fasciculations. Loss of the upper motor neurons leads to decreased coordination for skilled tasks, stiffness and spasticity, and increased (“brisk”) spinal reflexes. The most widely known MND is Amyotrophic Lateral Sclerosis (ALS), also known as Lou Gehrig’s disease, in which both upper and lower motor neurons are affected. Other forms include Primary Lateral Sclerosis (PLS), which affects primarily the upper motor neurons, and often has a less severe course than ALS, and Progressive Muscular Atrophy (PMA), which affects primarily the lower motor neurons. MND are considered neurodegenerative disorders with gradual progression and severe disability, often leading to death in few years. If a MND is suspected, you should see a neuromuscular specialist who will order or perform an EMG [link to EMG section], which can confirm or exclude the diagnosis.  Sometimes other conditions can mimic MND. If you have MND, regular visits to your neuromuscular specialist are important.  Since the disease can progress rapidly, changes in breathing, speech and swallowing function can occur and require supportive treatments. Although the prognosis remains poor and most patient die within 5 years from diagnosis, there have been significant improvements in survival and quality of life, mostly associated with better supportive treatments such as gastrostomy tubes and non-invasive ventilation. Riluzole is the only approved medication for MND and has been associated with modest extension of life expectancy.

Muscular dystrophy (MD) is a group of neurological conditions with defects in structural proteins in the muscles, causing progressive muscle weakness. Most MDs have a genetic and hereditary component and several genes have been identified for specific syndromes. There are many different types of MD. The best known is Duchenne MD and the milder Becker MD, both due to defects in the muscle protein called dystrophin found on the X chromosome and affecting only boys. Emery-Dreifuss MD causes wasting and weakness of the shoulders and upper arms and the calf muscles of the legs, as well as contractures in the elbows, neck and heels, and a heart rhythm problem known as conduction block. Facioscapulohumeral (FSH) MD begins in the teenage years and causes progressive weakness in muscles of the face, shoulders and chest with lesser involvement of the arms and legs. Limb-girdle muscular dystrophy (LGMD) affects the large muscles of the shoulders and hips. Myotonic dystrophy presents in adulthood with muscle spasms, cataracts, cardiac abnormalities, and endocrine problems. Individuals with Myotonic MD often have long, thin faces, droopy eyelids, and a swan-like neck. Oculopharyngeal muscular dystrophy (OPMD) predominantly affects the eye movement muscles and those associated with speech and swallowing. Diagnosis of these MD syndromes is made by a neuromuscular specialist based on the pattern of weakness, changes in serum CK (a muscle enzyme that is increased in blood due to muscle breakdown), muscle biopsy, EMG and genetic testing. Since the heart is a muscle that is affected in several forms of MD, we often obtain an EKG, echocardiogram and x-rays. While there is no specific treatment for most MD, steroids can help in some cases. A few medications are under investigation for specific MD types. Rehabilitation and exercise programs are also helpful.

Neuropathy is a generic term that refers to damage to the peripheral nerves that transmit messages from the central nervous system to the muscles, glands and organs, as well as sensory information from the skin and special senses to the brain. When there is injury to a single nerve it is called a mononeuropathy, as seen in carpal tunnel syndrome where the median nerve is compressed by a tendon at the wrist. When it occurs at multiple nerves it is called polyneuropathy. Nerve diseases can be classified as “demyelinating” when they affect the protective layer covering the nerve fibers and help them conduct impulses more quickly, or “axonal” when they involve the nerve fibers (axons) themselves. Sometimes the damage starts at the toes and progresses upward over time. This is the pattern when neuropathy is due to a metabolic disease like diabetes or a vitamin deficiency. Sometimes the injuries are spotty affecting different nerves, as seen with vasculitis. The damage can also be specific to motor nerves that control the muscles, sensory nerves or autonomic nerves.

Sometimes nerve diseases can present suddenly with rapidly progressive weakness due to inflammation, as in the Guillain-Barre syndrome (GBS), which often requires hospitalization and intravenous treatments such as intravenous immunoglobulin (IVIG) which reduces the immune response to the nerves, or plasma exchange in which antibodies are removed from the blood in a “blood-washing” dialysis machine, usually every other day for 5 treatments. Recovery from GBS may take many weeks and require inpatient rehabilitation. GBS is usually a single episode that does not recur, but a variant disease called CIDP can cause fluctuating symptoms of weakness and sensory changes and require long term therapy to suppress the immune response.

There are many causes for neuropathy, including mechanical trauma, toxins, vitamin deficiencies and hereditary genetic diseases like Charcot-Marie-Tooth disease. Diabetes is one of the most common causes of neuropathy, and commonly causes numbness, tingling and pain at the feet. A number of medications, particularly cancer chemotherapy, can cause neuropathy. Your neuromuscular specialist may perform an EMG to determine the location, type and severity of the nerve disorder, and order blood tests to check for diabetes, vitamin deficiencies and other possible causes. Genetic testing may be appropriate if there is a family history of nerve disease.

Medications for neuropathy can help with symptoms such as burning and pain associated with neuropathy, but do not help the weakness or numbness and do not prevent the neuropathy from progressing. Treating the cause of neuropathy, such as improving control of blood sugar for diabetic neuropathy, stopping toxic exposures or vitamin supplements for vitamin-deficient neuropathies can help prevent further nerve damage.

Call 1-84-GET-UCONN or request an appointment online with one of our specialists.