COLUMBUS, Ohio -

It’s estimated some five million Americans are battling Alzheimer’s disease, but by 2050, those numbers are predicted to nearly triple.

Doctors say if Alzheimer's disease is caught in the early stages, they have a better chance of treating it. But studies show most Alzheimer's patients wait three to four years before being treated.

Now researchers have developed a simple test that can help spot problems early. It's called the SAGE test. That stands for Self-Administered Gerocognitive Exam. It's designed to detect early signs of cognitive, memory or thinking impairments.

Dr. Douglas Scharre and his team at the Ohio State University Wexner Medical Center developed the test. A new study shows it can reveal a lot about a patient's mind.

"What we found was that this SAGE, self-administered test, correlated very well with the very detailed cognitive testing," said Scharre.

Researchers gave the test to more than a thousand patients over five years and found nearly 30 percent showed early signs of cognitive problems they didn't know they had.

Some of the questions involve basic math, others test memory or ask test takers to identify common objects.

By repeating the test from time to time, doctors have an inexpensive and easy way to monitor their patients and detect even slight changes.

"If we see this change, we can catch it really early and we can start treatments much earlier than we did without a test," said Scharre.

The test doesn't diagnose diseases like Alzheimer's, but the study suggests it is an effective screening tool.

It's free to download the test, but you do need to take it to your doctor to have it scored.

To download the test, visit the SAGE website, and after agreeing to the terms and conditions you can take the test by clicking one of the yellow boxes.