The trial brings up an interesting statistical quirk, but one that can have big implications for studies like this.

Researchers in China enrolled 348 patients who had an acute ischemic stroke within the past 7 days. They were randomized 1:1 to the Ginkgo group or usual care.

This is problem number one. No placebo control. Patients knew they were getting Gingko – an ancient herb that might help improve their brain function. That knowledge alone might be enough to move the needle a bit on cognitive tests.

How much was the needle moved?

The primary outcome here was based on the Montreal Cognitive Assessment, or "MOCA".

This is a validated test for cognitive impairment, with higher scores being better – much like the mini mental status exam we know and love.

Take a look at the MOCA scores over time in the two arms of the trial.