The mother of a close friend is in the early stages of Alzheimer's disease. The once-lively woman can still function enough to enjoy a daily trip to the local coffee shop with her husband and hasn't forgotten the names of her two children, but my friend admits it's hard to carry on a conversation with her mom these days. Her mother can't remember if she's repeating herself when she tells a story, so she withdraws into her own world.

"I get very frustrated and sad, and then it turns to anger," admits my friend (who didn't want to be identified). "I remember how brilliant she was."

Memories: First in, last out

The expression, First in, last out ... Last in, first out, is a short way of explaining that the things we learned long ago, like in childhood or when we were young adults, stay in people with Alzheimer's memories longer than things they learned or experienced recently. That's why they can't remember a conversation that happened 20 minutes ago, but they can remember events from 20 years ago.

Of course as the disease progresses, long-term memory is also impacted, and the person may forget the names of loved ones and other information that is stored in long-term memory.

How memory loss happens

In order to understand why patients with Alzheimer's disease lose their memory, it's helpful to know how the brain creates memories. Once a person with a healthy-functioning brain learns something new or has an experience – whether it's when they're five or 55 – it registers in the part of the brain called the hippocampus, which sends that memory or info to other parts of the brain for storage. That "storage bank" retrieves the memory. When Alzheimer's starts to take hold, the hippocampus is one of the first areas of the brain to be damaged. Because this part of the brain doesn't remember that the event (or person) ever took place, it can't assist in retrieving the memory.

As the disease progresses, memories start to slowly dissipate. "The first thing that gets affected is the ability to take in new memories," explains Dr. Amanda Smith, M.D., medical director of the Byrd Alzheimer's Institute at the University of South Florida. Sometimes, Dr. Smith says, new memories that don't have the same emotional attachment are stored in a different place than other memories, which is why an Alzheimer's patient whose disease has progressed might remember an event from 20 years ago, but can't remember what they did 20 minutes ago.

As a result, you cannot teach mom to not repeat herself because the hippocampus cannot register the teaching or send it to the storage units of the brain -- this is caused by damage to the hippocampus.

When plaque builds up in the brain's nerve cells – one of the causes of Alzheimer's – memory and thinking are impacted. That is one of the causes of confusion among people with Alzheimer's disease and their inability to organize their thoughts or remember the faces of people closest to them.

The frustration caregivers have as their loved one slowly starts to forget treasured memories is understandable.

"It takes an emotional toll on the caregiver," explains Louise Kenny, LCSW, a bereavement counselor at Avow Hospice in Naples, Florida. "They grieve watching their loved one lose their memory."

Kenny advises caregivers to educate themselves as much as possible about the disease, so they will be prepared for the many progressions that are likely to take place.

"Really understanding the type of dementia your loved one is going through will make care giving a bit easier. If you can keep that in the forefront, realize that it's not intentional, but that there are physical and neurological reasons for memory loss."

Regular routine can help

No doubt, patience is required to be the caregiver of an Alzheimer's patient. Kenny suggests that caregivers keep a regular routine for their loved one because research shows that patients respond to consistency. Kenny also tells caregivers that as the disease progresses, they may need to reduce the amount stimulation or noise their loved one is subjected to because it can make patients disoriented.

Browse Our Free Senior Care Guides

Care for the caregiver

While caregivers want to do what is best for their loved one, it's also important for caregivers to be mindful of their mental and physical health. To avoid burn out, Kenny stresses that caregivers reach out to others and find a support network where they can share their concerns, fears and even frustrations. Too many times, notes Kenny, the world starts to narrow for caregivers - just as it does for Alzheimer's patients - and they find themselves isolated. Kenny reminds caregivers not to lose touch with friends whom they can turn to when their loved one passes and they experience the grieving process.

Keep your sense of humor

Finally, Kenny advises caregivers to keep a sense of humor. At the moment, laughter is the best medicine for my friend. While her mom understands the seriousness of her diagnosis, she also likes to joke about her memory loss. "My mom says she can laugh or cry, and she'd rather laugh," says my friend. "So that's what we do."