In the last decade, new instruments have been used to study ALS patients very carefully. These studies have led to the identification of biomarkers such as proteins that are in the blood and brain fluids that can be used to predict disease progression. Sometimes we can use such methods to distinguish ALS patients that have different underlying causes.
Geevasinga, N., et al., Pathophysiological and diagnostic implications of cortical dysfunction in ALS. Nat Rev Neurol, 2016. 12(11): p. 651-661.