Familial ALS- ALS cases are inherited from 2 or more family members, affects 5-10% of ALS cases.

Sporadic ALS- disease occurs at random with no clearly associated risk factors; most common form of ALS, affects approximately 90-95% ALS cases.

Interventional trial- study where exposure, for example a drug, is assigned; used to determine the effectiveness of a treatment or intervention.

With drugs and a placebo- One group gets the active treatment, the other gets the placebo. Everything else is held the same between the two groups, so that any difference in their outcome can be attributed to the active treatment.

Observational study- study in which patients are observed and where no treatment is given; researcher has no control over the experiment because they are done in a more natural setting than an interventional trial.

Trial Phase- objectives are different for each phase of a trial.

• Phase I, drug is given to a small number of people to see if it is safe.
• Phase II begins to look at effectiveness of the drug.
• Phase III is considered the definitive test of whether a drug is effective, held at multiple research sites and much larger than the previous phases.

Vital Capacity- the maximum amount of air that can be expelled from the lungs after a maximum drawing of air into the lungs, measured by a spirometer and then scored as a percentage.