While PPA robs people of their ability to speak and understand language, an unusual twist of the disease is patients are still able to maintain their hobbies and perform other complicated tasks for a number of years before other symptoms develop. Some people garden, build cabinets and even navigate a city subway system. By contrast, Alzheimer's patients lose interest in their hobbies, family life and may become idle. As PPA progresses over a number of years, however, patients eventually lose their ability to function independently.
Preliminary evidence from the study also seemed to connect another form of dementia to a vasectomy. In a smaller group of 30 men with a dementia called frontotemporal dementia (FTD,) 37 percent had undergone a vasectomy. The earliest symptoms of FTD are personality changes, lack of judgment and bizarre behavior. As in PPA, FTD usually starts at an earlier age, in the 40s and 50s.
One of Weintraub's patients with FTD was eating lunch in a restaurant with his family and excused himself to go to the bathroom. When he hadn't returned after 10 minutes, his sons went to investigate. They found him doing pushups on the bathroom floor. Other FTD patients begin shoplifting, compulsively gambling, misspending large amounts of money or become sexually demanding.
The most common form of dementia caused by brain deterioration in individuals over age 65 is Alzheimer's disease. Weintraub did not find an increased rate of vasectomy in patients with Alzheimer's.
Many patients with FTD and PPA share a common brain disease that is completely different from Alzheimer's. Whether a patient will get the behavioral or language problems depends on where the disease causes the most destruction in the brain. In FTD, most of the damage is in the frontal lobes; in PPA, it's in the language centers of the left hemisphere of the brain.