As a clinician always looking for basic helpful activities that can improve brain function, I was especially interested in your last comment. Human interaction, in my own clinical experience, will indeed discourage cognitive deterioration.
Those that stay locked in and alone fall apart cognitively more quickly.
Research at UCLA regarding Mirror Neurons shows with fMRI [functional brain imaging] that we actually learn through the process of mirroring in our "mind's eye" the activities of others, even through the visual stimulation of watching ads on the Super Bowl!
The two most common problems I see in my practice are: 1. Drug interactions, long a favorite topic, and 2. Chronic metabolic disturbances not recognized over time leading to relative malnutrition.
Thanks,