Pattern analysis of sleep-deprived human EEG

Waking EEG Cortical Markers of Chronic Pain and Sleepiness

Objective

Spectral power analyses of EEG recordings are reported to distinguish the cortical activity of individuals with chronic pain from those of controls. Further study of these spectral patterns may provide a greater understanding of the processes associated with chronic pain, in addition to providing potential biometric markers of chronic pain for use in both clinical and research settings. However, sleep deprived groups have demonstrated similar characteristics in their spectral power characteristics, particularly in alpha bandwidth power activity.

Methods

103 individuals with chronic pain provided resting awake EEG data in addition to ratings of pain and sleep quality. Two Principal Axis Factor analyses using Promax rotation produced one pain and one sleep factor from relevant questionnaire data provided by participants. These factors were then used to test hypothesized relationships with alpha and theta bandwidth power at the frontal and parietal areas of the cortex.

Results

Our findings suggest that reductions in alpha bandwidth power are independently associated with both chronic pain intensity ratings and measures of sleep deficits. Conversely, theta bandwidth power was not found to be associated with either chronic pain or sleep quality measures.

Conclusions

This study's findings support that chronic pain intensity and sleep deficits are related to the Alpha spectral bandwidth activity in individuals with chronic pain.

Effects of sleep deprivation on neural functioning: an integrative review

Sleep deprivation has a broad variety of effects on human performance and neural functioning that manifest themselves at different levels of description. On a macroscopic level, sleep deprivation mainly affects executive functions, especially in novel tasks. Macroscopic and mesoscopic effects of sleep deprivation on brain activity include reduced cortical responsiveness to incoming stimuli, reflecting reduced attention. On a microscopic level, sleep deprivation is associated with increased levels of adenosine, a neuromodulator that has a general inhibitory effect on neural activity. The inhibition of cholinergic nuclei appears particularly relevant, as the associated decrease in cortical acetylcholine seems to cause effects of sleep deprivation on macroscopic brain activity. In general, however, the relationships between the neural effects of sleep deprivation across observation scales are poorly understood and uncovering these relationships should be a primary target in future research.

Electroencephalographic changes after one nigth of sleep deprivation

Total or partial sleep deprivation (SD) causes degrading effects on different cognitive and psychomotor functions that might be related to electrophysiological changes frequently observed. In the present study, we investigated the effects of one night of sleep deprivation on waking EEG. Experimental protocol consisted of recording electroencephalographic data from eleven healthy young subjects before (baseline) and after (time 2) one night of sleep deprivation. A natural log transformation was carried out and showed a significant increase in theta T6 (p=0.041), O2 (p=0.018) and OZ (p=0.028); and delta T6 (p=0.043) relative power; and a decrease in alpha Fp1 (p=0.040), F3 (p=0.013), Fp2 (p=0.033), T4 (p=0.050), T6 (p=0.018), O2 (p=0.011) and Oz (p=0.025) and beta (p=0.022) absolute power. These outcomes show that the EEG power spectra, after sleep deprivation, exhibit site-specific differences in particular frequency bands and corroborate for the premise of local aspects of brain adaptation after sleep deprivation, rather than global.

Effects of total sleep-deprivation on waking human EEG: functional cluster analysis

OBJECTIVE

The purpose of the present study was to investigate the effects of total sleep deprivation (TSD) on brain functions with an identification procedure for strongly interactive brain regions, relying on functional cluster (FC) analysis in multichannel electroencephalogram (EEG) data.

METHODS

EEGs from 16 electrodes in 18 healthy, right-handed, young male volunteers were recorded before TSD (after normal sleep) and after 24 h of experimentally induced sleep deprivation. We estimated cluster index to characterize joint interactions among many brain regions in order to determine if a particular FC is present or not, and if so, its anatomy.

RESULTS

As a result, we confirmed the presence of FC and found different FC patterns in both before and after TSD. The C3 and F7 locations were outside the cluster under the TSD condition, but belonged to the cluster with C4 and F8 before the TSD condition, and the F3/F4, and O1 locations were new entries to the functional cluster during sustained wakefulness.

CONCLUSIONS

These results indicate that the neuronal activities of the C3 and F7 location are functionally unrelated, whereas the F3/F4 locations are functionally involved with the C4, F8, and O1 locations after 24 h TSD. Our results suggest that FC changes with elapsed awake time and reflects the change of brain function due to TSD.

SIGNIFICANCE

This paper shows the existence of FC both before and after TSD, and the anatomy of each FC is different. So FC analysis would be a potential tool to investigate the simultaneous neuronal activity of human EEGs.