Amyloid Plaques Found in Non-Alzheimer Elders

Early amyloid plaques may identify at-risk elders

(RxWiki News) Two brain-imaging techniques have been able to see brain deposits of amyloid beta, a precursor to developing amyloid plaques, in seemingly normal older individuals.

The amyloid plaques are a hallmark to Alzheimer's disease. This brain-imaging technique could help identify patients for therapies to prevent the development of dementia.

Senior author Keith Johnson, MD, Massachusetts General Hospital (MGM) Imaging and his colleagues think these findings support what they already hypothesized: Alzheimer’s disease begins many years before symptoms appear.

Finding the amyloid beta which can lead to amyloid plaques in non-Alzheimer's disease elders supports this theory.

"Brain deposits of amyloid beta may lead to earlier diagnosis of Alzheimer's disease."

The current study drew its participants from the Harvard Aging Brain Study. There were 87 normally cognitive older people and 32 people diagnosed with mild Alzheimer’s disease (AD) who all received both high-resolution magnetic resonance imaging (MRI) of brain structure and PET scanning with Pittsburgh Compound B (PiB) to detect amyloid plaques.

The results showed that those cognitively normal individuals had amyloid plaques in addition to structural changes in their brain.

These changes were similar but less pronounced than the neurodegenerative changes seen in the symptomatic patients. The most evident structural changes in the cognitive normal participants were in areas of the brain called the default network.

In Depth

  • The default network is known to be compromised early in Alzheimer’s disease
  • Researchers observed that if normal older adults had deposits of amyloid plaques and they are experiencing neurodegenerative changing like Alzheimer’s patients, we may be able to signify these older adults as ‘preclinical’ AD

Alzheimer's disease is the most common form of dementia in the United States affecting approximately 5.3 million people, and the number is growing. Alzheimer’s results in memory loss, decline in cognitive functioning, and behavioral changes. Alzheimer's disease is usually diagnosed clinically from the patient history, statements from relatives, and clinical observations. There is no cure, and treatment efforts are aimed at slowing the progression of the disease and treating its symptoms. Prescription medications such as Namenda (NMDA receptor antagonist) and Aricept (cholinesterase inhibitor) have been shown to slow progression by altering the amounts of certain neurotransmitters in the brain to improve neuronal communication.

Review Date: 
March 31, 2011