Signs of Alzheimer’s Disease Appear Early

Early Cognitive Changes in Preclinical Alzheimer’s Disease

Swedish researchers reviewed 47 studies published between 1983 and 2003, involving more than 10,000 participants. Of these, about 1,200 individuals had preclinical Alzheimer’s disease and later progressed to a formal diagnosis, while approximately 9,000 participants served as healthy controls.
The review, published in Neuropsychology (July 2005), found a consistent pattern: subtle cognitive changes appear years before Alzheimer’s disease is clinically diagnosed.

Across multiple studies, early indicators included:

• Mild problems with memory

• Subtle impairments in attention or executive function

• Reduced ability to learn new information

These changes were often detectable long before standard clinical testing would label the individual as having Alzheimer’s disease, suggesting that cognitive decline begins well before the disease is recognized.

This work contributed to the modern understanding that Alzheimer’s is a long, slow process—and that early cognitive screening may help identify at-risk individuals sooner.