This is a study of quantitative electroencephalographic (QEEG) comodulation analysis, which is used to assist in identifying regional brain patterns associated with Chronic Fatigue Syndrome (CFS) compared to an EEG normative database. Further, this study investigates EEG patterns in depression which is found to be a highly comorbid condition to CFS. The QEEG comodulation analysis examines spatial-temporal cross-correlation of spectral estimates in the individual resting dominant frequency band. A pattern shown by Sterman and Kaiser (2001) and referred to as the Anterior Posterior Dissociation (APD) discloses a significant reduction in shared functional modulation between frontal and centro-parietal areas of the cortex. Conversely, depressed patients have not shown this pattern of activity but have disclosed a pattern of frontal Hypercomodulation localized to bilateral pre-frontal and frontal cortex. This research investigates these comodulation patterns to determine whether they exist reliably in these populations of interest and whether a clear distinction between two highly comorbid conditions can be made using this metric.
Sixteen CFS sufferers and 16 depressed participants, diagnosed by physicians and a psychiatrist respectively were involved in QEEG data collection procedures. Nineteen-channel cap recordings were collected in five conditions: eyes-closed, eyes open, reading task-one, math computations task-two, and a second eyes-closed baseline.
Five of the 16 CFS patients showed a clear Anterior Posterior Dissociation pattern for the eyes-closed resting dominant frequency. However, 11 participants did not show this pattern of dysregulation. Examination of the mean 8-12 Hz band spectral magnitudes across three cortical regions (frontal, central and parietal) indicated a trend of higher overall alpha levels in the parietal region in CFS patients who showed the APD pattern compared to those who did not show this pattern. All participants who showed the APD pattern were free of medication, while the majority of those absent of this pattern were using antidepressant medications. For the depressed group, all of which were medication free, 100 % of the depressed group showed a frontal Hypercomodulation pattern. Furthermore, examination of the mean 8-12 Hz band spectral magnitudes across three cortical regions disclosed a trend of high frontal alpha and a left/right asymmetry of greater voltages in the left frontal cortex.
Although these samples are small, it is suggested that this method of evaluating the disorder of CFS holds promise. The fact that this pattern is not consistently represented in the CFS sample could be explained by the possibility of subtypes of CFS, or perhaps comorbid conditions. Further, the use of antidepressant medications may mask the pattern by altering the temporal characteristics of the EEG. This study, however, was able to demonstrate that the QEEG was able to parse out the regional cerebral brain differences between CFS and depressed group.
| Identifer | oai:union.ndltd.org:ADTP/265544 |
| Date | January 2004 |
| Creators | Lorensen, Tamara Dawn |
| Publisher | Queensland University of Technology |
| Source Sets | Australiasian Digital Theses Program |
| Detected Language | English |
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