Bedside EEG for rapid diagnosis of delirium

Delirium is a frequent complication among older adults and is linked to higher mortality, longer hospital stays, and greater healthcare expenditure. Although its clinical relevance is well recognized, routine diagnosis remains challenging because existing tools rely largely on the observation of fluctuating symptoms, which can easily be overlooked in daily practice. Electroencephalography (EEG) provides an objective measure of brain activity, and characteristic changes such as generalized slowing have been consistently described in patients with delirium. Despite these established findings, the conventional EEG setup is technically demanding and not well suited for repeated use in general hospital wards. In recent years, portable point-of-care (POC) EEG systems have been developed, allowing recordings with a limited number of electrodes at the bedside. Several clinical studies have reported that these devices are able to detect delirium with acceptable accuracy, while also offering practical advantages such as rapid deployment and use by non-specialist staff. Among the approaches investigated, the bispectral EEG (BSEEG) method has attracted particular attention. A higher BSEEG score has been shown to correlate with delirium severity and to predict adverse outcomes, including reduced survival, even in patients who did not present with overt clinical symptoms. Beyond the clinical setting, experimental work has applied EEG and BSEEG to rodent models of delirium induced by inflammation or surgery. These studies have highlighted associations between EEG slowing, microglial activation, and behavioral disturbances, suggesting that electrophysiological changes may provide a translational link between basic mechanisms and clinical phenomena. Preclinical data also indicate that BSEEG could serve as a quantitative tool for assessing treatment response in experimental models. Taken together, these findings support the potential of simplified EEG platforms to complement current diagnostic strategies. If further validated in larger, real-world cohorts, bedside EEG may become a practical adjunct for the early recognition of delirium and the monitoring of disease progression, with implications for both patient outcomes and mechanistic research.