The ability to recognize a smell—or not—could indicate if your brain is injured or sick, recent studies suggest.

Research accomplished by the U.S. Department of Defense indicates that a weakened sense of smell predicted frontal lobe damage in soldiers suffering from battle-related injuries. According to the work, “Quantitative identification olfactometry has limited sensitivity but high specificity as a marker for detecting acute structural neuropathology from trauma,” or put simply, brain examination indicates test subjects demonstrating the weakest sense of smell were more likely to show proof of injury than those subjects whose sense of smell tested as normal.

Another study that shows the relationship between smell and brain function was documented by Dr. Davangere Devanand of Columbia University, New York. A June 2015 press release notes that “In a recent study of older adults, those with a reduced ability to identify certain odors had an increased risk of dying during an average follow-up of 4 years.” According to the work done by Columbia’s Department of Psychiatry and New York State Psychiatric Institute, the mortality rate of participants with the lowest scores on a 40-item smell test was 45 percent, compared with only 18 percent of the participants with the highest scores. “The increased risk of death increased progressively with worse performance in the smell identification test,” according to Dr. Devanand, “and was highest in those with the worst smelling ability.”

Photos via Bradley Gordon | Flickr Creative Commons