A neurological test is medical. A cognitive test is usually conducted by a psychologist. It determines ability to reason, memory, judgement, etc. JB has admitted he hasn't taken the test and doesn't need it.
This is the test that Trump brags about acing, and has received the highest score ever.
Hey, I'm not calling for Biden to back out. I would love to see the two of them go head to head in a basic cognitive exam and see a true physical from DJT