Wednesday, April 14, 2010

New, Low Cost Way to Predict Alzheimer’s Disease

According to scientists a low-cost behavioral assessment can clue someone in to Alzheimer’s disease at its earliest stage. The experts report the ability to detect changes in the progression of mild cognitive impairment (MCI).

MCI is a condition that affects language, memory, and related mental functions. It is distinct from the ordinary mental degradation associated with aging and is a likely precursor to the more serious Alzheimer’s disease. Both MCI and Alzheimer’s are linked to a steady decline in the volume of the hippocampus, the area of the brain responsible for long term memory and spatial reasoning.

MRIs (magnetic resonance imaging) are a reliable and direct way to detect hippocampal atrophy and diagnose MCI. But for many, the procedure is unavailable or too expensive according to Jesse Slome, executive director of the American Association for Long-Term Care Insurance.

Researchers created a much cheaper alternative, based on a memory test, that correlates with hippocampal degradation. From a computer model of an atrophying hippocampus, the researchers determined how to estimate capacity with a statistical measure of how quickly tasks are completed. Applying this analysis to a memory test for people with MCI, the researchers were able to gauge their hippocampal capacity and compare it to the progression of their ailment.

The researchers gave this test to five groups of participants: college students, healthy middle-aged adults, healthy elderly individuals, people with diagnosed cases of MCI, and a control group of age-matched individuals without MCI. The first three groups each had 100 members and the last two each had 50.

They analyzed the response times for the tasks and the number of items that were recalled, with and without additional cues. The MCI group showed the greatest sensitivity to added cues — the additional input either substantially helped or inhibited their performance. But like the computer model, estimates of capacity highlighted the greatest cognitive difference between the MCI group and the others.