It may be that loneliness may affect systems in the brain dealing with cognition and memory, making lonely people more vulnerable to effects of age-related decline in neural pathways, he suggested.

BBC: NEWS | Health | Loneliness link with Alzheimer's

Stage IV: This stage is commonly associated with more significant cognition problems and memory loss.

FORBES: The Stages Of Traumatic Brain Injury: Learning From The Brains Of Athletes, Veterans, And One Head-Banger

Up to a third of cases are fatal and those who survive may face memory loss, impaired cognition and motor difficulties (the virus affects the nervous system).

CNN: ON DEADLY GROUND

For Merzenich, improving memory and cognition among older people is just the beginning.

FORBES: Sharp As A Tack

Ira Hyman, a professor at Western Washington University who specializes in human memory and cognition, contends that mobile devices are more distracting for parents than radio, conversation and other outside-the-home diversions of yesteryear.

WSJ: The Perils of Texting While Parenting