How can the same brain plasticity-based training programs help individuals with cognitive losses arising from normal aging, exposure to IED explosions, or chemotherapy?

Over the years, I have specifically discussed the potential value of intensive brain plasticity-based brain fitness training for individuals with ALL of these (and other, related) personal histories. How in the heck can “one size fit all”? How on earth can the losses in mental faculties stemming from an explosion of little bubbles in the…