A History and Review of Quantitative Electroencephalography in Traumatic Brain Injury

Abstract

The electroencephalogram (EEG) is a physiologic measure of cerebral function that has been used by some to assess coma and prognosticate survival and global outcome after traumatic brain injury (TBI). Surface recordings of the brain's electrical activity reveal distinct patterns that indicate injury severity, depth of unconsciousness, and patient survival. The data produced with traditional qualitative studies, however, does not allow resolution and quantification of the wave frequency spectrum present in the brain. As a result, conventional EEG typically has only been used for gross and qualitative analyses and is not practical for use in long-term patient monitoring or as a sophisticated prognostic tool. One area of investigation that is working to address the limitations of conventional EEG has been the development and implementation of Fourier Transform (FT) EEG which resolves and quantifies frequency bands present in the brain. When FT analysis is applied to EEG, it provides concurrent and continuous monitoring, resolution, and quantification of all frequencies emitted. This review discusses the history and significance of conventional EEG and provides a review of how FT-EEG, commonly referred to as Quantitative EEG (QEEG), is being used in the clinical setting. The specific applications and significance of QEEG methods regarding treatment of patients with TBI are discussed in detail. The advantages, disadvantages, and future directions of QEEG in TBI are also discussed.

An Overview of the Use of Neurofeedback Biofeedback for the Treatment of Symptoms of Traumatic Brain Injury in Military and Civilian Populations

“…4,12,13,[17][18][19][20][21][22][23][24][25][26] The EEG, which records electrical activity of the brain over time, was introduced in 1929 and was shown to respond to volitional control via operant conditioning by 1962. 12,18,27 More recently, with the corresponding technological advances computers provided, quantitative EEG, which digitizes the EEG signal, has been introduced as the newer generation of EEG neurofeedback. This allows for more clinical sensitivity and specificity, although protocols and use of the equipment can vary from practitioner to practioner.…”

“…This allows for more clinical sensitivity and specificity, although protocols and use of the equipment can vary from practitioner to practioner. 4,12,18,[27][28][29] EEG patterns have been shown to be different in individuals following TBI, and have even been shown to predict prognosis in some cases. 7,12,26,27 Sideeffects from neurofeedback can include headaches, nausea, dizziness, fatigue, and agitation.…”

“…4,12,18,[27][28][29] EEG patterns have been shown to be different in individuals following TBI, and have even been shown to predict prognosis in some cases. 7,12,26,27 Sideeffects from neurofeedback can include headaches, nausea, dizziness, fatigue, and agitation. 18 These are common symptoms that TBI survivors seek to mitigate that might be worsened by the use of a computer screen to provide feedback, which can exacerbate symptoms in some patients with brain injuries.…”

“…18 Although the research still lacks a large body of randomized, double-blinded, placebo-controlled studies following standardized protocols, the literature does suggest that survivors-in both civilian and military populationsof brain injuries of differing levels of severity report improvements across a wide range of complaints of problems with attention, impulse control, processing speed, shortterm memory, and mood. 4,8,[12][13][14][15][17][18][19][20][21][22][23][24][25][26][27][28][29] Research on the use of neurofeedback for veteran populations has often focused on its use when PTSD or substance abuse is comorbid with TBI from blast injuries, with significant improvements reported, once the original protocol was modified. 18,28 Generalizability from the research is complicated by not only the lack of randomized, double-blinded, placebo-controlled studies following standardized protocols, but also by the variety of types and causes of TBIs.…”

Mild traumatic brain injury: Graph-model characterization of brain networks for episodic memory

“…Several investigations have applied electrophysiological methods (EEG, MEG, and ERPs) to study brain function in MTBI (e.g. Ford and Khalil, 1996;Gaetz et al, 2000;Gaetz, 2002;Lewine et al, 1999;Nuwer et al, 2005;Pointinger et al, 2002;Gaetz and Bernstein, 2001;Nuwer, 1997;Wallace et al, 2001;Thatcher et al, 1989), although EEG studies of memory task-related changes in MTBI are scarce. In normative studies, episodic memory has been studied extensively with the majority of studies focusing on EEG oscillations in the alpha and theta bands (e.g., Doppelmayr et al, 1998;Klimesch et al, 2001aKlimesch et al, , 2008.…”