Whether it happens to you, a friend, or a family member, an ALS diagnosis can change your world overnight. At TDI, we’re here to help you arm yourself with the knowledge you need to fight ALS.

We've compiled a selection of the questions we hear the most, along with answers from our researchers and other TDI staff members. If you don’t find the answers you need here, feel free to ask your question.

At any given time, there are over 30,000 patients diagnosed with ALS living in the United States; the number world-wide is estimated at around 400,000. Generally speaking, someone is diagnosed with ALS every 90 minutes. The life-time incident rate for an average person is often estimated at between 1/400 to 1/600 - a number that is similar to the incidence of multiple sclerosis; a disease, however, having a substantially longer average survival prognosis and thus larger living patient population.

There are two broad categories of ALS - sporadic (sALS, essentially of unknown cause) and familial (fALS, with a direct genetic linkage). fALS cases are typically identified by examining the medical history of ancestry with typical fALS affecting approximately half the members of the family tree. Several specific genes have been linked to the inherited disease which is estimated to be between 10 - 20% of all cases. To date, epidemiological studies have not consistently identified clear causative agents for the remaining 80 - 90% of sporadic disease. ALS seems to affect males and females at the same rate and there have been no indications that prevalence is higher based on ethnicity or other demographic variable. While the average age of onset is about 50 years old, cases are not uncommon in adults as young as 18 and as old as 80.

A comprehensive report conducted by the National Academies' Institute of Medicine (IOM) supports the association between service in the U.S. military and increased risk of developing ALS. The IOM was charged with reviewing and evaluating all relevant scientific literature on ALS and veterans. It concludes that there exists "suggestive evidence of an association between military service and later development of ALS." Since 2000, studies have been conducted to assess the ALS incidence rate in Gulf War veterans. Most notably, a study jointly funded by the VA and DOD concluded that those deployed in the first Gulf War were twice as likely to develop ALS as their non-deployed counterparts, and potentially, at younger ages. Air Force veterans, it determined, faced the highest risk, at 2.7 times that of those not serving. In 2005, The Harvard School of Public Health broadened the case for ALS's military relevance. Its epidemiological study found that men with a history of any military service in the last century were nearly 60% more likely to die of ALS than men in the general population. The recent IOM report refers to this study as "well-designed and well-conducted." In July 2008, in response to the evidence, Secretary of Veterans Affairs Dr. James B. Peake announced that ALS is to be considered a presumptively compensable illness for all veterans with 90 days or more of continuously active service in the military.

ALS is essentially a diagnosis of exclusion; elimination of other possible diseases until ALS is left as the only diagnosis. Depending on the strength of criteria used, there can often be some chance that ALS is misdiagnosed.

ALS is considered to be a fatal disease with many patients succumbing to loss of ability to independently breathe. The average survival is often estimated at 30 months post symptom onset, but progression varies and up to 10% are estimated to survive 10 years or longer. Survival can also be extended, potentially indefinitely, if a patient opts for mechanical ventilation intervention.

There is considerable variation in the natural history of the disease across patients but many patients observe initial symptoms in a specific muscle group such as the thumb or the disease may manifest as 'foot drop', etc. This initial muscle weakness will, with varying progression, typically spread laterally (to the opposite limb) or vertically, affecting muscles on the same side. Symptom initiation in the chest or neck/mouth is often referred to as bulbar onset. Progression rates vary across individuals and have been reported in some cases to alter within individuals as the disease progresses.

PLS neurodegeneration is restricted to only upper motor neuron while ALS diagnosis requires the observation of progressive loss and involvement of both upper and lower motor neurons. Publications suggest that PLS tends to be a slowly progressing disease but that the majority of diagnosed patients will eventually progress to a situation of involvement of lower motor neurons and thus the diagnosis altered to ALS.

There is currently one rodent model that is widely accepted by researchers as modeling human ALS. This model is based on version of the mutated, human SOD1 gene. Mice or rats bred to carry multiple copies of the altered human gene develop symptoms very similar to clinical ALS. These animals provide a basis for evaluation of drug efficacy potential in studies that are similar to a clinical trial as well as a source for tissue for experimentation.

Currently, there is no effective therapeutic approved for use by the FDA that has been identified to stop the disease's progression or prevent onset. Rilutek is a drug that has been approved for use in the treatment of ALS; however it offers a very modest effect which has usually been described as a three-month life extension. The effectiveness of Rilutek varies from patient to patient and all medical treatment decisions should be made in careful consultation with one's physician or other qualified medical professional charged with their care.