PiB was assessed in older individuals with no signs of Alzheimer’s, according to paper in Archives of Neurology.
Professors at the University of Pittsburgh School of Medicine have developed an imaging agent that they believe could facilitate the early diagnosis of Alzheimer’s disease. Pittsburgh Compound B (PiB) finds Alzheimer’s-associated plaques in symptom-free older adults by binding to the amyloid proteins.
In the study, 43 people between 65 to 88 years who had no impairment on cognitive testing were scanned with PiB and PET. Nine of them showed early amyloid deposition in at least one area of the brain. That suggests there may be as many people in this age group with these early brain changes but no visible symptoms of Alzheimer’s disease as there are people with recognized Alzheimer’s disease.
A surprising finding was that detailed tests of brain functioning showed no decrease in functioning among participants whose scans revealed the presence of the Alzheimer-associated amyloid deposits.
“The good news is it appears the brain can tolerate these plaques for years before the effects are apparent,” comments senior investigator, William E. Klunk, M.D., Ph.D., professor of psychiatry and neurology at the University of Pittsburgh School of Medicine. “The bad news is that by the time the symptoms emerge, the disease has had perhaps a 10-year head start.”
Dr. Klunk cautioned that although researchers suspect that people with amyloid deposits and normal brain functioning have a high risk of developing Alzheimer’s disease in the future, the team does not yet have proof of that fact and can therefore not tell the research participants the results of their PiB scans according to study protocol.
The study is published in this month’s issue of the Archives of Neurology.