Swedish researchers reviewed 47 studies, involving over 10,000 people. The studies, published between 1983 and 2003; 1200 of the subjects had preclinical Alzheimer’s disease and eventually developed the disease and 9,000 of the subject       s were healthy. The research appeared in the July 2005 issue of the journal Neuropsychology. The researchers noticed that cognitive problems in the patients who eventually developed preclinical Alzheimer’s disease appeared early, before they are actually diagnosed with the disease.