5. Smell “coffee” with your eyes closed.
This is a slightly different test to test the youthfulness of the brain. Close your eyes, cover your left nostril with your finger, and smell a strong odor such as coffee or peanut butter with your right nostril only. Then try the same sniff with the opposite nose. This has been noted as a clue to detecting early signs of brain dysfunction, such as memory loss. Brain function may weaken from the “ability to sense smell” before memory. If there is a clear difference in “smell intensity” between left and right sides, it may be a sign that the brain is tired.
