Author: Wang Andrew
Date: October 2007
Advances in the diagnostic criteria for Alzheimer's Disease (AD) are giving hope to physicians, patients, and family members for earlier diagnosis and treatment. Researchers led by Dr. Howard Feldman, Head of the Division of Neurology at the University of British Columbia's Faculty of Medicine, have developed new guidelines for the diagnosis of AD based primarily on the structure of the brain. AD may now be diagnosed when patients are experiencing only slight to mild degrees of cognitive impairment; an improvement on current guidelines which often delay treatment until severe dementia has already set in.
As the most common cause of dementia, AD is a neurodegenerative disease that results in cognitive deterioration. The Alzheimer Society of Canada estimates that the disease currently affects more than 238,000 Canadians and approximately $5.5 billion is spent each year on caring for affected individuals.
Established and unchanged since 1984, the current diagnostic criteria involve a two-step approach: evaluating functional disability and then looking for a cause. This often wastes valuable time that patients and physicians alike cannot afford to lose, resulting in more cases of severe and untreatable AD. "Integrating the profound neurobiological advances of the last 20 years allow for diagnoses based on more than declining functional ability," says Feldman, "we now have advanced diagnostic tools distinctive and reliable biological indicators that can be detected before the patient crosses the dementia threshold of disability."
The new diagnostic criteria include a core of clinically determined early, progressive, and significant episodic memory loss accompanied by one or more biological indicators characteristic of AD.
Such indicators include atrophy of the temporal lobe (visualized in an MRI), abnormal amyloid Beta protein concentrations found in the cerebrospinal fluid, a pattern of reduced glucose metabolism seen in PET scans of the brain, and a genetic mutation for AD.
With these criteria in hand, early detection will allow for preventative vaccines or other drug regiments that target the early stages of the disease. However, further validation studies are required to improve the sensitivity and accuracy of these new measures.
Author: Andrew Wang
Reviewed by: Frances Mao
Published by: Konrad Sawicki