Functional Neuro-Imaging and Post-Traumatic Olfactory Impairment

OBJECTIVE: To evaluate via a research literature survey the anterior neurological significance of decreased olfactory functioning following traumatic brain injuries. MATERIALS AND METHODS: A computer literature review was performed to locate all functional neuro-imaging studies on patients with post-traumatic anosmia and other olfactory deficits. RESULTS: A convergence of findings from nine functional neuro-imaging studies indicating evidence for reduced metabolic activity at rest or relative hypo-perfusion during olfactory activations. Hypo-activation of the prefrontal regions was apparent in all nine post-traumatic samples, with three samples yielding evidence of reduced activity in the temporal regions as well. CONCLUSIONS: The practical ramifications include the reasonable hypothesis that a total anosmic head trauma patient likely has frontal lobe involvement.