that next. first, the science of cognitive training. think aerobics but your mind, it's helped super bowl quarterback tom brady win big. rachel crane has this week's teching care of your health. see what i did there? >> what is this exercise test? >> it improves visual speed and attention. >> how does cognitive training work? >> we can build brain exercises that rewire the brain. it achieves the goal of being faster -- we actually built more than 29 exercises that target memory, speed, attention, people skills, navigation, intelligence. >> there's a good amount of controversy surrounding the efficacy of these brain training tools. >> sure. independent and academic review reviewed cognitive training programs and pointed out some of them have no evidence and some