Electroencephalography and network connectivity in delirium

Abstract

Delirium is a common and serious neuropsychiatric condition which is associated with acute change in attention, orientation, and other cognitive functions as a result of an underlying medical condition. These changes can be identified by quantitative EEG analysis techniques (qEEG), which have increasingly been used in recent years to study delirium. The objective of this review is to provide an overview of studies on neurophysiological changes in delirium using various qEEG analysis techniques. Studies have shown that in delirium, there is an increase in delta and theta activity, which are the slowest frequencies in the EEG spectrum, but a decrease in activity in the alpha frequency band, which is associated with wakefulness and attention. Additionally, there is a decrease in functional connectivity and efficiency of the brain network in the alpha frequency band, indicating a disruption in the communication between different brain regions. These result suggest a potential for neuromodulatory interventions such as transcranial electrical stimulation as treatment for delirium. Despite the promising results of qEEG analysis in delirium diagnosis, there are still some limitations that need to be addressed. For example, the variability in EEG patterns among patients with delirium and the lack of standardized EEG protocols for delirium diagnosis can make it challenging to identify specific neurophysiological changes that are unique to delirium. In conclusion, delirium is characterized by diffuse slowing of the EEG, reduced functional connectivity, and decreased efficiency of the brain network. These findings suggest that improved functional connectivity could be a new approach to treat delirium. Future research should aim to address the limitations of EEG research in delirium diagnosis and to further explore the potential of qEEG analysis as a tool for delirium diagnosis and treatment.