Willis and associates released the 5-year results in JAMA last December and the results were really positive. All 3 kinds of cognitive programs were shown to have an impact right away after the program, after 3 years, and after 5. The results of the group that used a computer-based program to train processing speed revealed clear short-term and long-lasting results. Individuals who experienced enhanced speed of processing likewise revealed much better performance on jobs of important activities of day-to-day living such as quickly discovering a product on a congested kitchen shelf and reading medication bottles. They also reacted to road signs faster. We discovered this transfer of training in our prior studies using the training method too.
Simply put, significant portions of the participants improved their memory, information-processing and reasoning speed throughout all 3 methods. The most impressive outcome was that, when checked 5 years later, the participants in the computer-based program had less of a decline in the skill they were trained in than did a control group that received no cognitive training.
To respond to the very first question, I would state that a crossword puzzle is not a form of cognitive training. It can be promoting, however it is not a type of structured psychological exercise that has been shown to improve certain cognitive skills – besides the ability of doing crossword puzzles, of course.
In terms of the second question, it is too early to say whether we can actually reverse decline in a permanent method. There are lots of skills included and the studies are not long enough to really compare various trajectories. What we can say is that by doing some workouts, one can enhance cognitive speed of processing by 146-250 %, and that a significant portion of that improvement remains even after 5 years. We can not state more definitively.