Olfactory Changes After Military Deployment Are Associated With Emotional Distress but Not With Mild Traumatic Brain Injury History

Objective The aim of the study was to identify the impact of mild traumatic brain injury history and current emotional status on olfactory functioning. Design This was a cross-sectional study of 49 predominantly male, military veterans, reservists, and active duty service members with Operations Enduring Freedom, Iraqi Freedom, and New Dawn deployments and varying mild traumatic brain injury histories. Results Those with a positive history of mild traumatic brain injury (n = 32) endorsed significantly higher rates of self-reported olfactory disturbance. However, there were no differences between the mild traumatic brain injury and no mild traumatic brain injury groups for rates of objective odor identification dysfunction (none vs. microsmia or more severe) or overall accuracy of odor identification. In keeping with this, self-reported olfactory disturbance also failed to associate with odor identification dysfunction. In both groups, those self-reporting olfactory disturbance reported significantly greater emotional distress, severity of posttraumatic stress symptoms, and attentional impulsivity. However, self-reported olfactory disturbance was not associated with other behavioral factors frequently attributed to TBI, such as aggression, motor impulsiveness, poor planning, and cognitive flexibility. Conclusions These findings indicate mild traumatic brain injury is not a risk factor for postacute microsomia among Operations Enduring Freedom, Iraqi Freedom, and New Dawn military veterans. Higher observed rates of self-reported olfactory disturbance in patients with mild traumatic brain injury may be a function of emotional distress rather than organic brain injury.