Quantitative and Qualitative Analysis of Ambulatory Electroencephalography During Mild Traumatic Brain Injury

OBJECTIVES: To characterize the neurophysiological changes in a patient with mild traumatic brain injury (mTBI) and to compare these changes with a small cohort of patients with neurocardiogenic syncope, an analogous cause of transient neurological dysfunction. DESIGN: Case report and quantitative analysis of a small electroencephalography (EEG) cohort. SETTING: University-affiliated teaching hospital. PATIENTS: A 64-year-old man with mTBI recorded on ambulatory EEG. The comparison group was 4 patients with spontaneous neurocardiogenic syncope during continuous video EEG recording. INTERVENTION: Quantitative and qualitative analysis of EEG. MAIN OUTCOME MEASURES: Changes in quantitative EEG measurements between the patient with mTBI and the comparison group. RESULTS: In the patient with mTBI, there was an abrupt decrease in high-frequency (beta) power and alpha-delta ratio immediately after the injury and a corresponding increase in lower-frequency (alpha, theta, delta) power. The change in beta power resolved within 5 minutes of the injury, but the increases in low-frequency power persisted up to 20 minutes after the injury before resolving. Similar but smaller changes were seen in the patients with syncope, but these changes resolved within 5 minutes, with no intermediate or long-term changes. CONCLUSIONS: The quantitative EEG changes in mTBI are initially similar to those in syncope, suggesting acute transient cortical dysfunction. However, there are longer-lasting increases in low-frequency power during mTBI, suggesting ongoing disruption of cortical-thalamic circuits.