Can a Smell Test Help Identify Traumatic Brain Injury?
Can your ability to smell help medical professionals diagnose you with a brain injury? According to a new study by Federal researchers published in the journal Neurology, that might be the case.
The study led by Air Force Colonel (Dr.) Michael Xydakis, associate professor of Surgery in the F. Edward Hebert School of Medicine at the Uniformed Services University of the Health Sciences (USU), and his colleagues from USU, Walter Reed National Military Medical Center, and the National Institutes of Health, finds decreased ability to identify specific odors is a strong predictor of abnormal neuroimaging results in blast-injured troops, and testing the sense of smell may be a potentially useful in assessing memory impairment following trauma.
For the study, researchers evaluated over 231 acutely injured polytrauma inpatients at Walter Reed National Military Medical Center who had been air-evacuated from the combat zone in Afghanistan or Iraq. All participants in the study were evaluated for traumatic brain injury before being administered a test assessing their sense of smell.
The sense of smell processes the countless different odors we encounter by sending signals to the brain which associate the information with past memory. When memory is impaired, such as in the case of traumatic brain injury, it can be difficult for the brain to properly complete this task. The researchers believe their findings support this idea, as participants who performed abnormally on the smell test were all found to have abnormalities present on their brain scans.
“Although it may seem far-fetched that the sense of smell can be used to identify a concealed brain injury, olfactory impairment was commonly used by neurosurgeons in attempts to localize certain brain tumors prior to the use of advanced neuroimaging in the 1980s,” said Xydakis.
The results lead researchers to conclude similar smell testing could be used in combat theater to help physicians assess which injured troops need immediate neuroimaging.
“Having a stable, field-portable olfactory diagnostic kit is key,” said Xydakis. “We approached Southwest Research Institute, which has more than 60 years of experience with various microencapsulation techniques, to help develop test kits to accurately and consistently diagnose TBIs even in harsh, often erratic, battlefield conditions.
“Getting a CT scan in a combat zone is often the equivalent distance of placing a soldier on a helicopter in Washington, D.C., and sending them to Boston. It requires a significant investment in personnel and aviation resources; not to mention flying troops over hostile terrain. Using abnormalities with the sensory systems has opened up an entirely new avenue of investigation for diagnosing brain injuries,” Xydakis said.