http://www.amenclinics.com/cybcyb/exercise-fitness/table-tennis-is-the-worlds-best-brain-sport/
Avoid dementia by ....
Wear your seat belt.
Don't drink or stop drinking alcohol.
Diet and Exercise.
Life long learning.
Watch what you eat.
No smoking. Dead people don't get dementia.
Escape cancer drugs.
Chemical used for cosmetics may be problematic.
Time is, was and will be. Without time we would not be. What a load it has to carry! Time seems eternal! You might even ask whether cycles in time exist? If so read Roger Penrose's book on new attitudes in physics towards possible "Cycles in Time".