For Early Onset Dementia Patients, Workplace Fraught With Worry

When Diane Thornton first realized she was having trouble keeping track of appointments, she would write herself reminder notes. When she got lost on her way to the office, she'd call her secretary and ask for directions. On days she had trouble speaking or remembering words, she would avoid answering her phone.

But when in her psychotherapist practice she could not remember her patients' names, could not recognize the notes she had written in their files, could not understand the mounting paperwork it took to handle their claims, and could not trust herself not to say inappropriate things -- she knew there would be no quick fix, no easy cover up.

She would have to quit, and face the fact that at age 52 she had dementia.

Though she admits she has "no reference for time" and difficulty "remembering when things happened," she remembers one date in particular.

"August 15, 2006. That date really sticks on the brain. That's when I left my job. That's the day I lost my identity," Thornton said.

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Thornton, now 55, is one of the 200,000 Americans under age 65 estimated to be living with early onset dementia or Alzheimer's disease. Dementia, and its often attendant cause Alzheimer's, is marked by memory loss and declines in language and cognitive function. While it typically affects people in the final years of life, early onset dementia sometimes strikes people in their prime.

For a retiree with adult children, dementia is a frightening prospect. But for a middle-aged person with a mortgage and children who never anticipated early retirement, figuring out how to balance their diagnosis with their job adds another layer of anxiety to an already dire situation.

"I would forget the patient I was seeing. I'd look at my notes and at the patient's chart and I wouldn't recognize my own handwriting. After the HIPAA [privacy] laws changed there was all this new paperwork and I just could not keep track," Thornton told ABC News from her home in Memphis.

After months of seeing doctors, one of whom suggested she was just a "stressed-out soccer mom," Thornton received her diagnosis from a physician who "couldn't have looked more unhappy that I didn't have a brain tumor."