Autonomic symptoms develop later in the course of the disease, and death is usually due to repeated respiratory infections and progressive respiratory failure. Upper motor neuron UMN signs and symptoms include spasticity, hyperreflexia, bulbar signs and symptoms, and presence of the Babinski sign. Lower motor neuron LMN signs and symptoms include weakness, muscle atrophy, hyporeflexia, and muscle fasciculations.
UMN involvement may be localized to one region of the spinal cord e. Clinical, electrophysiological, and neuropathological evidence of lower motor neuron degeneration. Radiographic assessment, including neuro-imaging, is not diagnostic in ALS; radiologic studies are used to rule out other disease processes.
The MRI is usually normal. Motor neuron syndromes with lymphoproliferative disorders or other malignancies e. The etiology of ALS is unknown. In addition, neurons may be sensitive to glutamate-induced cell membrane damage. Males are more commonly affected than females before age 65 years; after age 65 years, men and women are equally affected. The peak age of diagnosis is in the seventh and eighth decades; however, ALS may be diagnosed as early as the third decade.
Additional laboratory studies may be helpful in establishing the diagnosis of ALS or in evaluating other diagnostic considerations:. Doctors may place a breathing tube through the mouth or may surgically create a hole at the front of the neck and insert a tube leading to the windpipe tracheostomy.
Although ventilation support can ease breathing problems and prolong survival, it does not affect the progression of ALS. Cellular defects. Ongoing studies seek to understand the mechanisms that selectively trigger motor neurons to degenerate in ALS, which may lead to effective approaches to halt this process.
Research using cellular culture systems and animal models suggests that motor neuron death is caused by a variety of cellular defects, including those involved in protein recycling and gene regulation, as well as structural impairments of motor neurons.
Increasing evidence also suggests that glial support cells and inflammation cells of the nervous system may play an important role in ALS.
Stem cells. Scientists are turning skin cells of people with ALS into stem cells that are capable of becoming any cell type, including motor neurons and other cells which may be involved in the disease.
NINDS-funded scientists are using stem cells to grow human spinal cord sections on tissue chips to help better understand the function of neurons involved in ALS. Genetics and epigenetics.
Other studies are working to identify additional genes that may cause or put a person at risk for either familial or sporadic ALS. A large-scale collaborative research effort supported by NINDS , other NIH institutes, and several public and private organizations is analyzing genetic data from thousands of individuals with ALS to discover new genes involved in the disease. By using novel gene editing tools, researchers are now able to rapidly identify new genes in the human genome involved in ALS and other neurodegenerative diseases.
Additionally, researchers are looking at the potential role of epigenetics in ALS development. Epigenetic changes can switch genes on and off, which can greatly impact both health and disease.
Although this research is exploratory, scientists hope that understanding epigenetics can offer new information about how ALS develops. NINDS supports research on the development of biomarkers—biological measures that help identify the presence or rate of progression of a disease or the effectiveness of a therapeutic intervention. Biomarkers can be molecules derived from a bodily fluid blood or cerebrospinal fluid , an image of the brain or spinal cord, or a measure of the ability of a nerve or muscle to process electrical signals.
New treatment options. This work involves tests of drug-like compounds, gene therapy approaches, antibodies, and cell-based therapies in a range of disease models. Additionally, a number of exploratory treatments are being tested in people with ALS.
The Registry includes data from national databases as well as de-identified information provided by individuals with ALS. All information is kept confidential. People with ALS can add their information to the Registry by visiting www. Clinical trials Many neurological disorders do not have effective treatment options. Clinical trials offer hope for many people and an opportunity to help researchers find better ways to safely detect, treat, or prevent disease.
For more information abuot finding clinical trials on ALS, visit www. Tissue from individuals with ALS is needed to enable scientists to study this disorder more intensely. The goal is to increase the availability of, and access to, high quality specimens for research to understand the neurological basis of the disease. It is not uncommon for people with progressive bulbar palsy to go on to develop ALS.
Myasthenia gravis is an autoimmune neuromuscular disorder that may also present in a similar fashion. Polio is a virus that attacks motor neurons in the anterior horn of the spinal cord, resulting in paralysis. Thankfully, due to aggressive vaccinations, this virus has largely been eradicated.
Some of those who have had the disease, however, may complain of a weakness known as post-polio syndrome. This may be due to aging or injury causing the relatively few surviving motor neurons controlling the movement of a previously affected limb to die.
The disorder only affects older people who have had polio in the past. It is usually not life-threatening. Kennedy's disease is due to an X-linked genetic mutation that affects the androgen receptor.
The disorder causes slowly progressive weakness and pain of the muscles closest to the torso. The face, jaw, and tongue are also involved. Women with the genetic mutation are carriers, with a 50 percent chance of passing the gene on to their children.
Women with the mutation may also suffer from minor symptoms, such as finger cramps, instead of more profound weakness. Because the disease affects the androgen receptor the receptor to which estrogen and testosterone attach , men with the disorder may also suffer from symptoms such as gynecomastia breast enlargement , testicular atrophy, and erectile dysfunction.
Spinal muscular atrophy is an inherited disease that predominantly affects children. It is caused by defects in the SMN1 gene and is inherited in an autosomal recessive pattern. Due to this defective gene, not enough SMN protein is made, and this leads to degeneration of lower motor neurons. This leads to weakness and muscle wasting. There are three main types of SMA, each involving children at a different age. There is no very effective treatment for any of the motor neuron diseases.
Medical therapy focuses on controlling symptoms of the disease as best as possible. However, in order to know what symptoms to anticipate, as well as rule out other more treatable diseases, it is important to get the right diagnosis. Using their physical exam and other techniques such as electromyography , nerve conduction studies, and genetic testing when appropriate, neurologists can help define the correct diagnosis.
Having the right diagnosis allows your neurologist to manage your symptoms as much as possible and to anticipate and prepare for any expected complications. In the beginning, we commented that "fortunately" motor neuron diseases are uncommon. This may be good unless you or a loved one develop one of these conditions. Then, in addition to suffering the symptoms of these diseases, you may find that there are less research and less support than you would hope.
While these diseases are uncommon, measures such as the Orphan Drug Act are directing more attention to these less common but no less important conditions. You may feel alone if you've been diagnosed with a motor neuron disease. Unlike the large groups of "breast cancer advocates" out there, we do not see huge groups of, for example, progressive bulbar palsy advocates. Yet awareness is rising, and at least for ALS, support.
People with motor neuron diseases need support just as those with more common conditions. ALS often starts in the hands, feet or limbs, and then spreads to other parts of your body. As the disease advances and nerve cells are destroyed, your muscles get weaker.
This eventually affects chewing, swallowing, speaking and breathing. There's generally no pain in the early stages of ALS , and pain is uncommon in the later stages. ALS doesn't usually affect your bladder control or your senses. ALS affects the nerve cells that control voluntary muscle movements such as walking and talking motor neurons.
ALS causes the motor neurons to gradually deteriorate, and then die. Motor neurons extend from the brain to the spinal cord to muscles throughout the body. When motor neurons are damaged, they stop sending messages to the muscles, so the muscles can't function.
For the rest, the cause isn't known. Researchers continue to study possible causes of ALS. Most theories center on a complex interaction between genetic and environmental factors. Environmental factors, such as the following, might trigger ALS. As the disease progresses, ALS causes complications, such as:. Over time, ALS paralyzes the muscles you use to breathe. You might need a device to help you breathe at night, similar to what someone with sleep apnea might wear.
For example, you may be given a bilevel positive airway pressure BiPAP device to help with your breathing at night.
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