One area where the DiPALS report may be flawed involves their discussion of whether ALS patients ought to undergo surgery, a reference being made to a paper by Pinto, et alia, published in 2004 suggested disease progression may increase in ALS patients who undergo surgery. They do not suggest constraining gastronomy tube surgeries, et alia or tracheostomy surgeries, however. Since I began observing remarks by ALS patients in 1999, the pacer was unanimously regarded as the least difficult of those who underwent same and expressed their opinion in on-line remarks I discovered. The DiPALS authors express an interest in the full set of data used by the FDA in support of the HUD/HDE determination; indeed I also wish this data, but even if such were available there are likely not enough cases to support conclusions needed to perfect medical opinion on the pacer. The symptom variance in ALS patients is very large and as a result, I estimated the number of cases needed to complete the medical review is likely more than 5,000 to 10,000 cases.

Their analysis was by intent to treat; Sandeep Gupta describes here:

Intention-to-treat concept: A review
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3159210/