Early Alzheimer's Detection Possible by New Chemical

Researchers reported that a new imaging technique has been found which helps to detect Alzheimer’s disease in the brain before any serious damage takes place.

The study has been mentioned in the December 21 issue of the New England Journal of Medicine, and states that a new imaging molecule dubbed as FDDNP stains the damaged brain tissue so it shows up on PET scans.

Research was carried on by scientists from the University of California, Los Angeles, and the molecule helped them to discriminate people with normal brains from those with mild cognitive injury and those with Alzheimer's disease.

Currently, the only way to detect the disease is to remove brain tissue or to perform an autopsy. The new study is part of a larger mission to find an enhanced method to diagnose the condition using tracers that can be detected with a PET scan.

Alzheimer's disease is a neurodegenerative disease characterized by progressive cognitive deterioration together with declining activities of daily living and neuropsychiatric symptoms or behavioral changes. It is the most common type of dementia.

The disease is characterized by the development of unusual clumps of proteins called amyloid plaques and nerve cell tangles that hinder messages being processed by the brain. The new chemical FDDNP attaches to these abnormal growths.

In the study, Dr. Gary Small and his colleagues discovered that the chemical allowed doctors to pick out which of 83 volunteers had Alzheimer’s, which had mild memory problems and which were functioning normally for their age.

All of the study volunteers also underwent magnetic resonance imaging (MRI) or computerized tomography (CT) scans for comparison.

The new chemical has 98% accuracy in determining whether an individual has Alzheimer’s or is suffering from a mild cognitive disability. The earlier methods used like the PET scan and magnetic resonance imaging had only 87% and 62% accuracy rate respectively.

“The FDDNP signal can be seen in people years before they develop Alzheimer’s disease”, Dr. Small said.

"I think this approach offers considerable promise for a brain test that might be used to detect who would benefit from future treatments," said study author Dr. Gary Small, director of the Center on Aging and a professor at the SEMEL Institute for Neuroscience and Human Behavior at UCLA.

"There is hope," Small said. "We are developing a technique that may not provide a cure, but may offer the next best thing -- identifying the problem before extensive brain damage and impairment in everyday life begins. It will likely be easier to protect a healthy brain than repair one that's already been damaged."

Small said that until effective treatments for the diseases has been found, this technique is of no use, but he appreciates that the chemical will be helpful in clinical trials, because it could give researchers a rapid and simple measure of how successful a treatment might be.

"This study is a small window into a much bigger story. Advanced imaging technologies -- including PET, MRI and others -- have great potential to improve early detection of Alzheimer's disease and may prove to be powerful tools in testing new therapies," said Dr. William Thies, vice president of medical and scientific relations for the Alzheimer's Association.

"A sensitive and accurate method for early Alzheimer's diagnosis that can also track the progression of the disease would help us treat people earlier and greatly speed testing of new drugs in treatment trials. Not having such a test is a major roadblock to efficient drug development," said Thies.

Thies revealed that FDDNP is not the only molecule which has been discovered to detect Alzheimer’s at an early stage. Another molecule, dubbed as the Pittsburgh Compound B (PIB) works in a similar manner on PET scans. However, Small said that PIB is not easy to produce and it only binds with the plagues and not the tangles.

According to Small, this is an important difference since previous research has proved that as cognitive impairment worsens, the tangle build-up speeds up.

In 2004, Alzheimer’s was the 7th leading cause of death in USA, with 65,829 numbers of deaths. AD is the third most costly disease in the U.S., after heart disease and cancer and it has been projected that by 2040, the number of people suffering from AD will have increased to 81 million.

The federal government estimates spending approximately $647 million for Alzheimer’s disease research in fiscal year 2005, and the average lifetime cost of care for an individual with Alzheimer’s is $174,000.