He used an observation about people with Down's syndrome. Potter recognized that all Down's patients, if they live long enough, will develop brain lesions identical to those detected in Alzheimer's sufferers. He came to discover that people with Down's syndrome are very sensitive to tropicamide, the drug used to dilate the pupil of the eye.
Potter then contacted Leonard Scinto, a neuroscientist at Brigham and Women's Hospital in Boston. They studied 58 people whose ages averaged 72: some had been diagnosed with Alzheimer's. After dropping a weak solution of tropicamide into the patients" eyes, the healthy patients dilated 4%, and those with the disease opened at least 13% (Gorman 89). There was one unusual case of a man whose eye-test results suggested that he had Alzheimer's, but who had exhibited none of the symptoms until nine months later when his memory deteriorated dramatically (Gorman 89). This showed that the test could work to detect Alzheimer's even before symptoms were noticeable.
Although imaging techniques can also detect the disease, they cannot be used routinely. Position Emission Topography, for example, takes several hours, uses highly specialized equipment, and involves injecting the patient with a radioactive isotope. This is not a routine procedure and it has its risks. Some non-burst MRI (magnetic resonance imaging) techniques can reveal changes in patients" brains, but so far they have not proved helpful in diagnosis (Beardsley 12). .
There is another type of imaging called burst MRI. It's different from other techniques because it takes just a few minutes and it can be done with an ordinary scanner. It allows the entire brain to be imaged in less than two seconds, without radioisotopes (Beardsley 12). These scans from patients with probable Alzheimer's show areas where blood flow is lower than in healthy people. So far, however, only eight patients have been studied.
