The predictive utility of preoperative electroencephalography for postoperative delirium

Abstract

Background: Postoperative delirium (POD) is associated with adverse outcomes in elderly patients after surgery. Electroencephalography (EEG) is an effective tool for identifying degenerative cerebral dysfunctions, including mild cognitive impairment and dementia. Methods: We included 237 patients aged > 70 years who underwent spinal surgery. We measured the median dominant frequency (MDF), which is a resting-state EEG biomarker involving intrinsic alpha oscillations that reflect an idle cortical state, from the prefrontal regions. Additionally, the mini-mental state examination and Montreal cognitive assessment (MoCA) were performed before surgery as well as 5 days, 1 month, and 1 year after surgery. Results: Forty-eight (20.3%) patients were diagnosed with POD. A multivariable logistic regression analysis that included age, MoCA score, Charlson comorbidity index score > 4, anaesthesia duration > 4 hours, and the MDF as variables revealed that the MDF had a significant odds ratio of 0.4 (95% confidence interval 0.23–0.77). Among the patients with POD, the postoperative neurocognitive disorders could last up to 1 year.Conclusions: In conclusion, a low MDF on preoperative EEG was associated with POD in elderly patients undergoing surgery. Our findings suggest that EEG could be a novel tool for identifying patients at a high risk of POD.

Prefrontal EEG slowing, synchronization, and ERP peak latency in association with predementia stages of Alzheimer’s disease

“…In addition, this MDF reduction has been found in patients experiencing a decline of brain functions, such as individuals with postoperative delirium or those exposed to methyl bromide. For instance, the postoperative delirium group showed a lower preoperative MDF than the non-delirium group; surprisingly, a sharp decrease in prefrontal MDF was observed after surgery under general anesthesia in both groups, and this effect remained even after 1 month (Kim et al, 2022). Similarly, a significant decrease was observed in prefrontal MDF after work exposure to methyl bromide, which is a fumigant that is widely used for killing pests (Park et al, 2020).…”