High IQ can mask early Alzheimer’s symptoms

The perception that better-educated people have less risk of Alzheimer’s disease has long stumped scientists.

But a new study at Columbia University Medical Center suggests that high IQ and more years of schooling may only camouflage the disease process. The educated brain seems to protect itself against symptoms early on, but once symptoms surface, scientists say there is a faster rate of decline.

“When symptoms finally do appear, their brains are already overwhelmed by the pathological disease process,” said Dr. Nikolaos Scarmeas, assistant professor of neurology and lead author of the study published this month in the Journal of Neurology, Neurosurgery and Psychiatry.

The scientists have been studying thousands of people older than 65 in upper Manhattan to better understand Alzheimer’s. The 312 men and women in this latest study did not show signs of Alzheimer’s when they entered the study, but a year and half later, the first symptoms developed. The scientists have followed them for more than five years.

At the study’s start, everyone completed neuropsychological tests, and scientists spent an hour examining each patient. They also obtained medical records, which in some cases included brain scans., There was a range of ethnicities among participants, and education varied from no formal schooling to 20 years.

“We think that these people can tolerate more changes and maintain their cognitive performance for a longer time,” Scarmeas said of those with the most education.

“The extra reserve capacity of the smart brain makes a person look like they don’t have a disease,” said James Mortimer, a professor of epidemiology and biostatistics at the University of South Florida in Tampa. “But the disease is a lot further along by the time the person is diagnosed.”

The problem, he added, is that as scientists get better at treating the disease, “we need to find these people earlier. If they are hiding behind their education, we can’t do that. We won’t find them in time.”