Departments of Neurology and Radiology, University of South Florida College of Medicine, and the Bay Pines Foundation
Approximately one to five million people suffer a
traumatic brain injury in the U.S. each year. The biomechanics of closed head injury involves fluid dynamic tissue boundary changes within the brain that include contusions of the gray
matter and shear force injuries to the
white matter. The mechanical consequences of a force imparted to the skull result in characteristic and quantifiable changes in the EEG and the MRI.
New methods of integrating QEEG have provided fresh insights into the physiological and electrical consequences of traumatic brain injury.
Increased amplitude of slow wave or delta frequency activity is correlated with white matter injury whereas
reduced amplitude of alpha and beta frequencies is correlated with gray matter injury. Mild traumatic brain injury primarily involves gray matter injuries whereas moderate and severe traumatic injury includes white matter injury. A spatial gradient of gray matter and white matter injury stemming from frontal and temporal cortex and extending to deep subcortical structures is reflected in both the QEEG and the QMRI. Gray matter injury is also correlated with reduced short distance EEG
coherence and increased long distance EEG coherence while white matter injury is correlated with decreased long distance EEG coherence. Reduced speed of information processing and reduced efficiency of information processing is reflected in specific patterns of the QEEG measures of amplitude, coherence and phase.
The integration of QEEG with QMRI is also helping to further our understanding of the 3-dimensional sources of electrical activity of the brain and may facilitate subcortical source localization procedures and eventually biofeedback of cortical and subcortical structures for the treatment of traumatic brain injury.