Posttraumatic Transient Neurologic Dysfunction: A Proposal for Pathophysiology.

Unexplained neurological deterioration is occasionally observed in patients with traumatic brain injuries. We aimed to describe the clinical features of posttraumatic transient neurologic dysfunction and provide new insight into its pathophysiology. We retrospectively collected data from patients with focal neurologic deterioration of unknown origin during hospitalization for acute traumatic brain injury for 48 consecutive months. Brain imaging, including CT, diffusion weighted imaging and perfusion weighted imaging, and electroencephalography were conducted during the episodes. Fourteen (2.0%) patients experienced unexplained focal neurologic deterioration among 713 patients who were admitted for traumatic intracranial hemorrhage during the study period. Aphasia was the predominant symptom in all patients, and hemiparesis or hemianopia was accompanied in three patients. These symptoms developed within fourteen days after trauma. Structural imaging did not show any significant interval change, and electroencephalography showed persistent arrhythmic slowing in the corresponding hemisphere in most patients. Perfusion imaging revealed increased cerebral blood flow in the symptomatic hemisphere. Surgical intervention and anti-seizure medications were ineffective in abolishing the symptoms. The symptoms disappeared spontaneously after 4 hours to one month. Transient neurologic dysfunction can occur during the acute phase of traumatic brain injury. Although transient neurologic dysfunction may last longer than a typical transient ischemic attack or seizure, it eventually resolves regardless of treatment. Based on our observation, we postulate that this is a manifestation of spreading depolarization occurring in the injured brain, which is analogous to migraine aura.