The brain is one of the most important organs in the body, and keeping it healthy is key to preventing life-threatening conditions that affect the vital organ.

Dr. Jonathan Rosand is a professor of neurology at Harvard University and treats patients with head trauma, spinal cord injuries and strokes at Massachusetts General Hospital. Rosand worked with a team of researchers to create a system that measures the health of your brain. It's called the Brain Care Score.

"I was getting a set of questions from patients and their families routinely. 'Doctor, how can I take good care of my brain so that I don't end up with a stroke like my father, or I don't end up losing my memory like my brother?'" Rosand tells CNBC Make It.

This prompted him to "explore opportunities for primary prevention of dementia, stroke and depression," which can be preventable by modifying risk factors like lifestyle choices. "For example, treating high blood pressure is one of the best ways to prevent both stroke and dementia," Mass General's Brain Care Score overview states.

To receive your score, which is on a 21-point scale, you take a quiz that asks you to indicate your dietary habits, blood pressure levels, social relationships and more. It takes about five minutes to complete. The higher your score, the healthier your brain.

The test asks questions about your daily behaviors and current health status like:

• What is your resting blood pressure?
• Do you smoke?
• Are you getting at least 150 minutes of moderate physical activity, or 75 minutes of high intensity physical activity per week?
• Do you sleep for less than 7 hours a night or have untreated sleep disorders?
• Are your stress levels manageable, or do you have difficulty functioning because of stress?

A higher Brain Care Score is associated with a lower risk of dementia, depression and stroke, according to a study published in Frontiers in Psychiatry. Last month, a paper printed in the medical journal Neurology supported the associations between a high Brain Care Score and a lower risk of developing brain diseases.

Even if your score is on the lower side, all hope isn't lost. Rosand suggests improving your brain health by working on one of your weaker areas.

"Whatever is most appealing to you in the beginning, that's where you start," he says. "So for some people, it's working on sleep. For other people, it's cutting down on alcohol."

Improving your score in one category will likely lead to an increased score in others, he adds. "If you sleep better, you're probably going to do better with blood pressure. Or if you exercise more, you're going to do better with sleep and blood pressure. They're all related."

Even people who have a family medical history of these diseases can improve their scores.

"We just published a study [that] looked at individuals [with a] high genetic risk for dementia, and found that raising your score cut even your genetic risk," Rosand says.

Here are the areas that the Brain Care Score considers:

• Blood pressure
• Blood sugar
• Cholesterol
• Body Mass Index
• Nutrition
• Alcohol intake
• Tobacco use
• Aerobic activities
• Sleep
• Stress
• Social relationships
• Meaning in life

"The key is to take the score as a guide and just use it for yourself to improve it, however you want to start improving it," Rosand says.

"It's really helpful when you go to the doctor if you bring the score with you and you've already decided, 'This is what I'd like to work on.'"

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