Abstract
Delirium is a multifactorial medical condition characterized by impairment across various mental functions and is one of the greatest risk factors for prolonged hospitalization, morbidity, and mortality. Research focused on delirium has proven to be challenging due to a lack of objective measures for diagnosing patients, and few laboratory models have been validated. Our recent studies report the efficacy of bispectral electroencephalography (BSEEG) in diagnosing delirium in patients and predicting patient outcomes. We applied BSEEG to validate a lipopolysaccharide (LPS)-induced mouse model of delirium. Moreover, we investigated the relationship between BSEEG score, delirium-like behaviors, and microglia activation in hippocampal dentate gyrus and cortex regions in young and aged mice. There was a significant correlation between BSEEG score and impairment of attention in young mice. Additionally, there was a significant correlation between BSEEG score and microglial activation in hippocampal dentate gyrus and cortex regions in young and aged mice. We have successfully validated the BSEEG method by showing its associations with a level of behavioral change and microglial activation in an LPS-induced mouse model of delirium. In addition, the BSEEG method was able to sensitively capture an LPS-induced delirium-like condition that behavioral tests could not capture because of a hypoactive state.
Competing Interest Statement
Corresponding author, Gen Shinozaki has pending patents as follows: [Non-invasive device for predicting and screening delirium], PCT application no. PCT/US2016/064937 and US provisional patent no. 62/263,325; [Prediction of patient outcomes with a novel electroencephalography device], US provisional patent no. 62/829,411. [DEVICES, SYSTEMS, AND METHOD FOR QUANTIFYING NEURO-INFLAMMATION], United States Patent Application No. 63/124,524. Takaya Ishii is employed by Sumitomo Pharma Co., Ltd. All other authors have declared that no conflict of interest exists.