[hmahncke]

For folks who dislike p-value reporting (and I'm one of them), we can focus on the effect sizes for speed of processing training in ACTIVE:

[1] 0.36 in slowing decline in functional abilities, equivalent to ~3 years of delayed decline [2] 48% reduction in at fault auto crash risk [3] 30% reduction in the risk of experiencing serious [0.5 s.d.] worsening of depressive symptoms [4] 29% reduction in dementia incidence [hazard ratio]

These are all clinically meaningful effect sizes.

Regarding the dementia incidence study, it's correct that two of the cognitive training interventions did not show effects, and speed of processing training did. In my view, a straightforward interpretation is that different types of cognitive training are different (much like different small molecule pharmaceuticals are different), and consequently they have different effects on endpoints like dementia incidence.