MRI imaging of the brains of people with PPA shows the language part in the perisylvian region of the left hemisphere has shrunk. By comparison, Alzheimer's Disease targets the hippocampus on both sides of the brain.
One of the oddities about PPA is that even when people have lost their ability to speak, they are still able to maintain their hobbies and perform other tasks. "One of my patients redid his vacation home and rebuilt all the cabinets himself. Another took up sculpturing and one kept up her organic garden. We have patients who do very complicated things even when they can't put two sentences together," Mesulam said. Alzheimer's patients lose interest in their hobbies, family life and just sit doing nothing, he noted.
As PPA progresses over 10 to 15 years, however, patients eventually lose their ability to function independently.