What Is ALS?

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ALS (Lou Gehrig's disease) Q&A
What is ALS?
(the scientific answer)

Amyotrophic lateral sclerosis (ALS) is a progressive, degenerative disease of the nervous system. It is one of a group of diseases, called motor neuron diseases (MND), in which specialized nerve cells that control movement of the voluntary muscles gradually cease functioning and die. These nerve cells, called motor neurons, carry impulses from the brain to the brainstem and the spinal cord. The impulses are then carried to the muscles. The muscles respond to these messages by coordinated relaxation or contraction corresponding to willed movement. In ALS and other motor neuron diseases, motor neurons gradually deteriorate. Because the nerve cells that stimulate them have died, the muscle tissues waste away. This results in progressive muscle weakness, atrophy, and often spasticity, or excess muscle tone. Only the motor neurons are affected. Other nerve cells, such as sensory neurons that bring information from sense organs to the brain, remain healthy.

Are there other names for ALS?

ALS, also known as motor neuron disease (MND), is commonly called Lou Gehrig's disease for the famous New York Yankee's baseball player who died of ALS in 1941. ALS is sometimes referred to as Charcot's disease for the French neurologist Jean-Martin Charcot who identified the disease in 1869.

Who gets ALS?

Most who develop ALS are between 40 and 70 years of age, although the disease can strike at any age. Men are affected slightly more frequently than women. ALS occurs throughout the world regardless of racial, ethnic or socioeconomic status.

Some studies have identified areas that at certain times have appeared to have greater than expected numbers of cases. This has occurred in the past in the western Pacific islands and in parts of Japan and Australia. Other areas in the continental United States have been reported but have not stood up to careful epidemiological investigations.

How common is ALS?

More than 5,600 Americans are diagnosed with ALS each year or two new ALS cases per 100,000 people (incidence). Approximately 35,000 people at any given time are living with ALS in the United States or six to eight people per 100,000 population (prevalence). The incidence of ALS is close to that of multiple sclerosis and four times that of muscular dystrophy.

What are the symptoms of ALS?

ALS strikes people in different ways and progression of the disease is often irregular. Some of the early symptoms of ALS are:

  • Weakness or difficulty in coordination in one limb
  • Changes in speaking or swallowing
  • Unusual muscle twitches, spasms, or cramps
  • Unusual weight loss or loss of muscle bulk

The symptoms and clinical features of the disease depend on the location of the affected motor neurons. Speech and swallowing impairments are called bulbar symptoms. They indicate that neurons in the brainstem are affected. Weakness of the respiratory muscles, muscle weakness, and loss of mobility in the arms and legs are called somatic symptoms. They indicate spinal cord involvement. In classical ALS, a mixture of upper and lower motor neurons are involved, with both bulbar and somatic symptoms.

  • Lower motor neuron symptoms
    Weakness and muscle wasting are common when lower motor neuron involvement predominates. The patient or physician usually notices fasciculation, or muscle twitching. Fasciculation is a sign of muscle irritability, as the normal action of the lower motor neuron on the muscle is impaired. The sole involvement of lower motor neurons can be seen in a form of ALS called progressive muscular atrophy. Fasciculation is described as "benign" if there is no muscle weakness, atrophy, or impairment of motor function. Fasciculation is described as "pathologic" when it occurs in ALS with other symptoms.
  • Upper motor neuron symptoms
    Spasticity, or stiffness, in the lower limbs, face, or jaw indicates upper motor neuron involvement. Spasticity in the legs often produces severe walking difficulties. The patient may complain of heaviness, fatigue, stiffness, or lack of coordination of any affected limb. Reflexes are very brisk, or exaggerated. Outbursts of laughter or crying with minimal provocation can occur. This is called emotional lability and is referred to as a pseudo-bulbar affect. Both brisk reflexes and emotional lability involve the inability to inhibit reflexes.

How is ALS diagnosed?

The diagnosis of ALS is a "clinical diagnosis," meaning there is no specific test that gives a definitive answer. Before a diagnosis of ALS is confirmed, many tests must be administered to rule out illnesses with symptoms that may mimic ALS. These may include an MRI of the brain or spinal cord, an electromyography (EMG) study of nerve and muscle function and a variety of blood and urine tests. By evaluating these tests, the patient's medical history and performing a complete neurological exam, the neurologist can usually reach a definitive diagnosis.

It is always recommended that patients seek a second opinion by a neurologist experienced with ALS in order to decrease the possibility of an incorrect diagnosis. In some cases a definitive diagnosis can be made only after several months of observation and retesting.

What is the prognosis of ALS?

ALS progresses at different rates in each individual. The average survival for someone affected by ALS is three to five years. A small percentage of people have a very slow progression and live 10-20 years with the illness at various levels of disability. Weakness of the bulbar and somatic muscles produces a decline in speech, swallowing, and limb strength and function. The ALS patient usually remains alert throughout the course of the illness and retains normal sensation, vision, and bowel function. Bladder function is impaired in 1% of patients. Generally, ALS is not a physically painful condition. Discomfort can result from immobility and joint contractures, a shortening of muscles resulting in deformity. While most patients do not have loss of intellectual function, some may have subtle changes in mood, behavior, or personality. In a small minority of patients, more significant changes in behavior and judgment suggest a form of dementia.

Each ALS patient is unique in regard to the rate and characteristics of the progression of the disease. The Lois Insolia ALS Center provides a multidisciplinary approach to patient care, including an individualized treatment plan guided by the patient's personal preferences and wishes. Although the clinical progression can vary greatly, 50 percent of those diagnosed will succumb to the illness within five years of the onset of symptoms

What causes ALS?

It is likely that there are several different causes of ALS. Two genes have been identified that cause familial ALS. The causes of sporadic forms of ALS are still unknown.

One hypothesis is that a group of gene mutations inherited together predispose one to ALS such that a threshold is formed. Environmental factors may "push" someone over the threshold so that ALS symptoms occur. Both the predisposing genes and environmental factors are unknown at this time.

Is there any treatment for ALS?

Many of the symptoms of ALS are treatable, but there are no drugs available to cure the disease. Rilutekę, the first FDA-approved medication for the treatment of ALS, has been shown to modestly increase lifespan. Since it became available in 1996, two retrospective studies presented at the 12th International Symposium on ALS/MND in 2001 indicated that Rilutekę appears to have a greater impact on life expectancy than was reported in initial drug trials.

The quality of life of patients with ALS can often be improved by various treatments and interventions. Proper positioning, exercise, physiotherapy, and medications can help keep patients comfortable. Patients with significant bulbar involvement may require help to improve communication or ensure safe and adequate nutrition. A gastrostomy (feeding) tube may be suggested if there is recurrent pneumonia, high risk of aspiration (inhaling food or liquids into the lungs), inadequate nutrition, rapid weight loss, or extended feeding time. A wide range of devices and techniques can address problems with communication. Ultimately, ALS may result in respiratory decline, requiring consideration of respiratory support, including non-invasive ventilation such as a BiPAP (bilevel positive airway pressure), or a tracheostomy and a ventilator.

Is ALS inherited?

Familial (genetic) ALS accounts for 10% of all ALS cases. ALS is considered familial if there are two or more cases within the same bloodline. If no family history exists, the disease is termed sporadic and other family members are not thought to be at increased risk for developing the disease.

Are there diseases similar to ALS?

Although it is the most serious, ALS is one of a number of diseases affecting the nerve cell, or motor neuron. Some involve only upper motor neurons, which run from the motor cortex of the brain to the brain stem and/or spinal cord. Others involve lower motor neurons, which run from the brain stem and spinal cord to muscles.

  • Spinal muscular atrophy (SMA)
    SMA variations include childhood forms and a less frequent adult form, which involves only the lower motor neurons. Inheritance of adult SMA is autosomal recessive. Symptoms are generalized weakness and muscle wasting with muscle twitching. Onset is over 18 years into adulthood with variable progression and normal life expectancy.
  • Primary lateral sclerosis (PLS)
    PLS, a degenerative disease of the upper motor neurons only, has symptoms of progressive spasticity, difficulty in walking, and pseudobulbar affect. PLS affects the trunk, extremities and bulbar muscles. PLS is not considered to shorten life expectancy as it has a slow progression over the course of approximately 20 years. Because ALS may initially present with signs of only upper motor neuron involvement, a diagnosis of PLS has the potential to be reclassified as ALS if sufficient signs of upper and lower motor neuron involvement are present.
Spinal bulbar muscular atrophy (Kennedy's Disease)
Symptoms are weakness and muscle wasting of the bulbar muscles (throat and mouth) and skeletal muscles. Facial and muscle jumping is common; breast development, infertility and testicular wasting can occur. It usually affects only men. Females are carriers who are usually asymptomatic or have a mild form. Onset is adulthood with progression being slow and variable with normal lifespan. Inheritance is X-linked recessive.

From the Les Turner ALS Foundation website

What is ALS?
(the unofficial version) 

The Roommate

I’m learning how to grudgingly coexist in my body with ALS. After inhabiting this flesh mostly alone all these years (except three pregnancies when I willingly—eagerly!—shared) I suddenly have a roommate I despise who is sabotaging my every move. A roommate who follows me into the shower, yanking my hair back and throwing me off balance as I lean back to rinse out the shampoo.


A roommate who grabs my throat as I try to swallow, choking me, forcing me to cough and spew and sputter as I strive desperately to catch my breath. A roommate who fights dirty, trapping me in my bed, pinning my arm and legs with the weight of my comforter—a misnomer that provides no comfort, hasn’t been comforting in months, a traitor.


A roommate who slyly sticks her foot out to trip me, sending me flailing wildly, skidding face-first across the hardwood floor, slamming my nose into the baseboard. She snickers at my helplessness as the blood oozes from my nose and mouth, as I writhe in pain, as I cry out for help that does not come.


A roommate who steals from me, robs me of my independence, who blatantly rips me off without even trying to hide her larceny. She knows I can’t prosecute her; she is above the law.


A roommate who demands constant attention, inserting herself into every conversation, inviting herself along on every outing, insinuating herself into even the most private moments between a husband and wife. A roommate whose unwelcome presence wears on me until I can no longer elude her even in my dreams. She diminishes me, humiliates me, taunts me, terrorizes me, violates me.


But I won’t—I can’t—give her an inch. Whatever she takes from me will be a spectacular battle. I concede nothing. I’m a stubborn adversary drawn into a war I did not seek, fighting this enemy occupation until the bitter end.