https://www.ubisoft.com/en-us/game/rocksmith/plus ROCKSMITH as a skill trainer.
autumn.health passive mood tracking has no references likely semantic analysis. https://www.turing.ac.uk/research/interest-groups/data-science-mental-health
https://codeforces.com/blog/entry/23054 competitive programming
https://pdfs.semanticscholar.org/d480/900464ef8a78cf4702ae8b4a9c9a20a35cdf.pdf a few (7) validated apps for cognitive decline testing
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1474018/figure/F3/ Seattle longitudinal study. Aside from perceptual speed and numeric ability most cognitive ability declines starting at age 60 IN SEATTLE!
https://www.nber.org/papers/w28785 Lumosity brain games shows that learning drops in presence of high air pollution
https://www.lesswrong.com/posts/nvRauqCD3u5hdkLm9/chess-and-cheap-ways-to-check-day-to-day-variance-in "Thirdly, having a good day at chess seems pretty strongly associated with having a good day at high-cognition-requiring tasks in general. In fact, it seems like a better predictor of this than asking myself 'do I expect to be good at cognition today?'."
Gary recommends blog on memory
https://www.learningscientists.org/blog/2016/5/10-1 retrieval vs storage strength memory is about propriate recall to not get overwhelmed with sense data. " we should not do so immediately after having just studied (or taught) it, when retrieval strength is still very high." retreival strength is not always high and therefore there should be a test! see Ultralearning.