The Difference Between Alzheimer’s Disease and Primary Progressive Aphasia

Kimberly Williams-Paisley learns the difference between Alzheimer’s disease and primary progressive aphasia after her mother’s diagnosis with PPA. The two situations share many similarities, and it can be hard for the general public to understand how they differ.

We’ll outline these differences in this latest installment of our online book club speaking about Kimberly Williams-Paisley’s book, Where the Light Gets In. She writes about her mother’s experience with primary progressive aphasia.

How It Begins

The common age of onset for Alzheimer’s Disease and primary progressive aphasia is different. Williams-Paisley learns on page 82:

Most people diagnosed with AD are over sixty-five. The first symptoms of frontotemporal dementia (FTD) often become apparent in fifty- or sixty-year-olds, making the disease relatively more common among younger people. Dr. Mesulam told us that PPA often seems to affect women in their sixties, like my mother.

PPA may affect people much earlier. Additionally, PPA affects words first while Alzheimer’s disease affects memory. A doctor explains on page 82:

He’d based his conclusion on the fact that Mom’s difficulties really begun with speaking and writing, hallmarks of aphasia. PPA first attacked the part of her brain behind her forehead. This frontotemporal area is primarily responsible for language. Her memory was healthy. That alone set her apart from people with AD, whose earliest symptom is usually forgetfulness.

Language loss, not memory loss, is a hallmark of early PPA.

How It Ends

Williams-Paisley learns that the two conditions will resemble each other more towards the end stage. On page 82, the doctor warns:

As the disease progressed, he told us, she would need help going to the bathroom, showering, dressing, and eating. We would see behavioral changes. And most likely dementia would spread throughout her brain. Eventually, the symptoms would resemble the last stage of AD. We learned later that this meant she would probably disengage from her environment, rarely say a word, and eventually lose control of movement and the ability to swallow, among other things.

Williams-Paisley remembers that they waited for a “shred of good news” while the doctor outlined PPA’s progression, but there was none beyond the family being better equipped to understand the road ahead.

For more information on the differences between Alzheimer’s disease and primary progressive aphasia, see this earlier post on brain differences between the two conditions.