Early Detection Can Lead to Longer and Improved Quality of Life

Researchers on three fronts have discovered new approaches that could lead to an early diagnosis of Alzheimer’s disease (AD), which now affects more than five million Americans -- about 1.5 percent of the entire population. Two new studies involve electrical brain signals and structural changes in the brain, and a skin test study was reported in the past year.

EEG Signals

Researchers at Rowan, Penn, and Drexel universities determined that Alzheimer’s disease could be accurately diagnosed between 80 and 90 percent of the time by using electroencephalogram (EEG) signals. Alzheimer’s disease is often not diagnosed at all until a person dies unless tests are conducted at high-profile medical institutions in large cities. With this new technology, diagnosing the illness could be possible in almost any doctor’s office.

The EEG is non-invasive, simple to perform, and can be repeated as often as necessary. “Our methodology provides just one snapshot (of the disease) that is highly accurate,” says Dr. Robi Polikar, an electrical and computer engineering associate professor at Rowan University in New Jersey.

The results of the study were presented earlier this year at a joint meeting of the International Conference of Engineering in Medicine and the Biological Society of the Institute of Electrical and Electronics Engineers, and appeared in Computers in Biology and Medicine, April 2007.

Brain Structure Changes

People who develop dementia or Alzheimer’s disease begin to show changes in the structure of their brains years before memory loss begins, according to a study published in the April 17, 2007 issue of the journal Neurology.

Researchers led by Charles Smith, MD, at the University of Kentucky Medical Center, performed brain scans and tests of mental ability on 136 people over the age of 65 who were considered normal at the beginning of the study. The subjects were examined periodically over the next five years. At the end of the period, 23 people had developed mild cognitive impairment (MCI), which leads to Alzheimer’s.
The 23 who developed MCI had less “gray matter” in the memory processing areas of their brains compared to those who did not develop memory problems, even at the beginning of the study when they were considered to be normal.

“We found that changes in brain structure are present in clinically normal people an average average of four years before MCI diagnosis. Before now, we didn’t know if these brain structure changes existed or to what degree (they existed), before memory loss begins,” Smith says.

Skin Test

Last year, scientists at Blanchette Rockefeller Neurosciences Institute in Rockville, MD, used a simple test that detects protein in skin cells. The research team believes that Alzheimer’s disease changes the way the brain sends signals related to the inflammatory process. The new test detects these specific signals in skin cells.

Although not yet available in clinics, the authors claim 100 percent predictive accuracy in a small group of samples. If their findings are replicated in larger studies, the test is likely to be made available within a few months. Study results were published in the Proceedings of the National Academy of Science.

Implications

Treatment of AD is most effective when it is given before widespread impairment of brain function occurs. By diagnosing it before a person is even aware of diminishing mental ability, physicians can take steps early on to improve the quality of that person’s life.

The View from Duke

"Two of these methods offer refinements on technologies already commonly employed in the differential diagnosis of neurological disorders: brain electroencephalogram (EEG) and magnetic resonance imaging (MRI), allowing a proximal view of the brain function early in the disease course," says Kathleen Welsh-Bohmer, director of Duke's Bryan Alzheimer's Disease Research Center.

"The third study offers a very novel diagnostic angle, a 'skin test' to detect proteins related to abnormal cell signaling and inflammation. While additional study of all these procedures is needed to verify their utility, particularly in unselected populations, the reports underscore the growing demand for reliable biomarkers of AD, which would allow us to identify patients at the highest risk for dementia and permit clinical intervention before significant brain compromise has occurred."