When Deborah Bell's father was diagnosed with gallbladder cancer seven years ago, she knew something was off about her mother, Rosa.
She was mean, combative, detached and accusing Bell of being the "other woman" in her father's life. And when Bell's father was placed in hospice care and died in their home, Rosa had no idea what had happened to her husband.
But the biggest red flag came when Rosa went to let out the dog, turned the house alarm on, then forgot the alarm was on and couldn't remember how to turn it off.
After neighbors called Bell to tell her about the incident, rescuers were called and she was evaluated at the hospital.
Testing revealed her diagnosis: middle-stage Alzheimer's disease.
"My dad would always say to me 'your mom is crazy as hell,' but I thought it was just normal parents fighting kind of stuff," said Bell, of Dania Beach, Fla. "I would say to him, 'No Dad. Come on. I'm sure you are a little crazy too.' But looking back at it, she was going through Alzheimer's and we didn't know."
Alzheimer's is a slowly progressive brain disease - and the most common form of dementia - that destroys memory and cognitive skills and leads to behavioral changes. Although there are treatments available to delay the worsening of symptoms, there is no cure. Treatments include oral medications for symptoms of the disease, clinical trials, music and art therapy, creative writing and retention therapy, mentally stimulating activities and physical fitness.
The disease, which takes an average of eight to 12 years to fully progress, ultimately leaves individuals in a vegetative state in which they are unable to talk, walk or swallow.
According to the U.S. Department of Health and Human Services National Institute on Aging, symptoms of Alzheimer's usually appear after age 60, and it is estimated that as many as 5.1 million Americans have the disease.
Dr. Elizabeth Crocco, chief of Geriatric Psychiatry at the University of Miami Miller School of Medicine, says the behavioral changes are the most difficult part to manage and it is important to keep individuals with Alzheimer's stable and well for as long as possible.
"A steady routine is essential, and it is important to take care of physical health," she said. "People can live many years with this disease. The bottom line is that we can all go at any time. We want individuals with Alzheimer's to be able to live life to the fullest."
Bell moved into her mother's house to take care of her full-time while continuing her "second full-time job" as a middle-school teacher. She says her mother, now 85, can no longer carry out a conversation or complete daily tasks such as showering or dressing herself. She also doesn't recognize her daughter.
"At this point, she thinks I am her mom," Bell said. "She answers to me with, 'Yes ma'am,' but other days she'll have these lucid moments where she will look at me and say 'I love you.' That makes it all worthwhile."
Age is the primary risk factor for Alzheimer's disease followed by family history, genetics, major head trauma, repeated head trauma, diabetes and stroke.
As families prepare to get together for the holiday season, some individuals may notice changes in a family member's physical or cognitive health - especially elderly relatives - that can be the first sign of Alzheimer's disease.
According to the Alzheimer's Association, family members should be on the lookout for 10 important warning signs during the holiday season: Memory loss that disrupts daily life; challenges in planning or solving problems; difficulty completing familiar tasks; confusion with time or place; trouble understanding visual images and special relationships; new problems with words in speaking or writing; misplacing things and losing the ability to retrace steps; decreased or poor judgment; withdrawal from work or social activities and changes in mood or personality.
Jamie Brodarick, the program services manager for the Alzheimer's Association, says one in eight people with Alzheimer's live alone.
It is important for family members to be proactive.
"There are some normal age-related changes, but anytime these changes are interfering with a person's ability to have a normal daily routine then it is a problem," she said. "There are things you can do to make sure you are not dealing with a crisis situation."
Dr. Marc Agronin, a geriatric psychiatrist and the director of mental health and clinical research at Miami Jewish Health Systems, says early diagnosis is critical when it comes to Alzheimer's disease.
"The earlier you diagnose the memory changes, the more you can do," he said. "The sooner you identify, the more damage you can prevent."
The current theory for Alzheimer's disease is that by the time symptoms begin to appear, the process has been going on for several years. Although other forms of dementia are reversible, Alzheimer's is not.
Agronin says studies are working on using a new type of brain scan that uses dye to help identify the beta amyloid protein in the brain. People who have a certain amount of this protein are considered to have a higher risk for Alzheimer's disease, and then become involved in clinical trials.
Susan, whose husband Jim has moderate Alzheimer's disease, was involved in an immunotherapy clinical trial and is currently part of the Girsh Memory Enrichment Institute at Miami Jewish Health Systems - a program for individuals with cognitive impairment and their caregivers.
"It is difficult for a single caregiver to stimulate their loved one to keep things going," said Susan, who asked that her last name not be used for security reasons. "It's stimulation, which makes all the difference."
Agronin says caregivers need to remain hyper vigilant because disaster can be right around the corner. Depression, anxiety, behavioral changes, sleep disturbances and sexual dysfunction are all things that go with Alzheimer's.
"We are making gains in terms of understanding this disease, but we need help," he said. "Don't hesitate. And, don't give up hope. It is never too late to make changes to improve the situation. Even though we can't cure it, there are lots of different ways to care for the person."
Explore further: Scientists spot early signs of Alzheimer's disease