Senior spelling bee champ shares his secrets for staying sharp

Michael Petrina's mother passed away from Alzheimer's disease 15 years ago. That's one of the reasons the 67-year-old retired attorney works his mind so hard.

Petrina took first place in the AARP National Spelling Bee on Sunday, beating more than 50 contestants in 47 rounds. The winning word? Rhizoctonia, a genus of imperfect fungi.

"R-H-I-Z...," Petrina started to spell before breaking into laughter as he spoke to CNN Monday. "Is that right? I hope. I'll look it up while we're talking."

The AARP started the spelling bee in 1996 as a way to motivate members to keep their minds sharp.

While Alzheimer's and other types of dementia are a big concern for seniors, even normal aging can slow the brain's processes over time.