الفهرس 
Physiology of EEG & Quantitative EEGOnly 14 pages are availabe for public view
 |  | from | 190 |  |  |
| | | from | 190 | | |
Abstract
The electroencephalogram (EEG) is useful in the evaluation of patients with several types of neurological disorders, including seizures, cerebrovascular stroke, dementia, Parkinson’s disease, migraine, and traumatic brain injury.
The traditional method of EEG interpretation depends on visual analysis, which is subjective and time-intensive. During this interpretation, it is important to distinguish between cerebral activity and artifact.
Quantitative EEG (QEEG) is the mathematical processing of digitally recorded EEG in order to highlight specific waveform components, transform the EEG into a format or domain that elucidates relevant information, or associate numerical results with the EEG data for subsequent review or comparison.
Clinical quantitative EEG is a complex specialty that may include; spectral analysis, spectral coherence, Signal analysis (Automated event detection, Source analysis, Frequency analysis and Monitoring and trending EEG), Topographic EEG displays and Statistical analysis (Comparison to normative values and Diagnostic discriminant analysis).
Routine EEG is an established test commonly used in the clinical evaluation of patients with epilepsy. EEG testing can help to locate an epileptic focus or suggest the type of epilepsy. Some quantitative EEG methods have built on that established role. Digital spike and seizure detection can identify candidate events that might be epileptic spikes or seizures. In long-term EEG monitoring records of outpatients, inpatients, or Intensive Care Unit patients, candidate spikes or seizure events are selected automatically and saved for subsequent professional visual review and confirmation. This data reduction method is a valuable time-saving tool, especially in recordings lasting one or several days.
In cerebrovascular disease, several quantitative EEG parameters are highly correlated with regional blood flow or metabolism. When used by skilled professionals experienced in EEG interpretation, sensitivity and specificity are high for detection of ischemia-related cerebral impairment or similar focal impairment.
Routine EEG has long been an established test used in evaluations of dementia when the diagnosis remains unresolved after initial clinical evaluation. In occasional clinical evaluations, quantitative EEG frequency analysis may be a useful adjunct to interpretation of the routine EEG when used in expert hands.
Quantitative EEG frequency biomarkers could be useful in the general study of cognitive status in Parkinson’s disease as well as in treatment studies aimed at studying conversion from one clinical cognitive state to another. In clinical treatment trials, prevention or treatment of Parkinson’s disease cognitive decline would be expected to show changes towards normalization of the EEG frequency content.
Quantitative EEG can be used for evalutating cortical changes in migraine. Quantitative EEG-guided neurofeedback appears to be effective in reducing migraine frequency in patients with recurrent migraine headache.
Quantitative EEG studies in mild traumatic brain injury or concussion, have reported abnormalities in many features reflecting changes in brain function.EEG changes can be detected hours to months after mild traumatic brain injury.Quantitative EEG features have also been used in multivariate classifier functions to discriminate between mild and severe traumatic brain injury.
Quantitative EEG (QEEG) may be useful in the evaluation of mood disorders since many QEEG studies have shown increased alpha and/or theta power and interhemispheric asymmetry in depressed patients. There are evidences to support the usefulness of QEEG in schizophrenia, and other psychiatric disorders.QEEG can be used in differentiation between patients with schizophrenia and those with depression.
Specific electrophysiological patterns have been reported for anxiety disorders. The basal instability in cortical arousal, as reflected in measures of quantitative EEG, is common to most of the anxiety disorders.