Peggy Younes felt her head begin to spin in the middle of a Medicare forum loaded with acronyms, enrollment dates and possible coverage changes that could cost seniors who make the wrong choices.

"I sit back there and I start to laugh. I can't keep up," said the 76-year-old Oxnard resident. "I leave feeling like I really don't understand."

It's dazed-and-confused time for many seniors as they try to figure out whether they need to change their prescription drug plan or other aspects of their Medicare coverage.

Private companies that offer Medicare coverage began marketing their 2009 plans this month. The enrollment period during which beneficiaries choose Medicare plans for next year begins Nov. 15 and ends Dec. 31.

"Almost every plan changes every year," Medicare expert David Lipschutz of California Health Advocates said at Monday's forum held at an Oxnard senior center. He warned seniors not to assume last year's plan will continue to cover their needs.

"It doesn't pay to be complacent," he said.

The most confusing enrollment decisions facing seniors involve choosing a program to cover prescription drug needs and whether to use one of the Medicare Advantage managed-care programs offered by private companies as an alternative to traditional Medicare.

Lipschutz said the exact changes in prescription drug and Medicare Advantage plans aren't known yet. He advised seniors to carefully review the mail they get from their insurance providers detailing next year's coverage.

"There are so many seniors who don't understand this. They think it's junk mail," said Katharine Raley of the county's health insurance counseling and advocacy program.

She told seniors who feel overwhelmed to put all their mail together and review it with a county insurance advocate.

"You've got to do some planning, because it's your dollars you're going to lose if you don't," she said.

Raley said seniors might find a few companies that offered stand-alone prescription drug plans last year have dropped the programs for next year.

Lipschutz said new laws restrict how agents can recruit seniors for Medicare Advantage or prescription drug plans. They can't show up uninvited at your home. In most cases, they also can't call people unsolicited on the telephone. "Agents can't approach you in common areas like parking lots or outside of senior centers," he said.

U.S. Rep. Lois Capps, D-Santa Barbara, told seniors at the forum that she's pushing for reform that could bring better prices for prescription drugs and less subsidies for the private companies selling Medicare Advantage plans.

Capps expressed alarm at delays in Medicare payments that have angered doctors and caused at least one local surgeon to boycott the insurance program. She said she's fighting to expedite payments and wants program changes that attract doctors to Medicare, rather than push them away.

"I want people who provide Medicare to feel good about the program they're representing," she said.