Search

Background: Postoperative delirium is the most common complication following surgery among older adults, and has been consistently associated with increased mortality and morbidity, cognitive decline, and loss of independence, as well as markedly increased health-care costs. Electroencephalography (EEG) spectral slowing has frequently been observed during episodes of delirium, whereas intraoperative frontal alpha power is associated with postoperative delirium. We sought to identify preoperative predictors that could identify individuals at high risk for postoperative delirium, which could guide clinical decision-making and enable targeted interventions to potentially decrease delirium incidence and postoperative delirium-related complications., Methods: In this prospective observational study, we used machine learning to evaluate whether baseline (preoperative) cognitive function and resting-state EEG could be used to identify patients at risk for postoperative delirium. Preoperative resting-state EEGs and the Montreal Cognitive Assessment were collected from 85 patients (age = 73 ± 6.4 years, 12 cases of delirium) undergoing elective surgery. The model with the highest f1-score was subsequently validated in an independent, prospective cohort of 51 older adults (age = 68 ± 5.2 years, 6 cases of delirium) undergoing elective surgery., Results: Occipital alpha powers have higher f1-score than frontal alpha powers and EEG spectral slowing in the training cohort. Occipital alpha powers were able to predict postoperative delirium with AUC, specificity and accuracy all >90%, and sensitivity >80%, in the validation cohort. Notably, models incorporating transformed alpha powers and cognitive scores outperformed models incorporating occipital alpha powers alone or cognitive scores alone., Conclusions: While requiring prospective validation in larger cohorts, these results suggest that strong prediction of postoperative delirium may be feasible in clinical settings using simple and widely available clinical tools. Additionally, our results suggested that the thalamocortical circuit exhibits different EEG patterns under different stressors, with occipital alpha powers potentially reflecting baseline vulnerabilities., Competing Interests: Dr. E. Santarnecchi serves on the scientific advisory boards for BottNeuro, which has no overlap with present work; and is listed as an inventor on several issued and pending patents on brain stimulation solutions to diagnose or treat neurodegenerative disorders and brain tumors. Dr. A. Pascual-Leone is a co-founder of Linus Health and TI Solutions AG which have no overlap with present work. He serves on the scientific advisory boards for the ACE Foundation and the IT’IS Foundation, Neuroelectrics, TetraNeuron, Skin2Neuron, MedRhythms, and Magstim Inc; and is listed as an inventor on several issued and pending patents on the real-time integration of noninvasive brain stimulation with electroencephalography and magnetic resonance imaging, applications of noninvasive brain stimulation in various neurological disorders, as well as digital biomarkers of cognition and digital assessments for early diagnosis of dementia. Dr. M Berger has received private legal consulting fees related to perioperative neurocognitive disorders. None of the other authors report any conflicts of interest. All the other co-authors fully disclose they have no financial interests, activities, relationships and affiliations. The other co-authors also declare they have no potential conflicts in the three years prior to submission of this manuscript.

Background: The glymphatic system represents an extravascular network of astrocytic channels responsible for interstitial fluid and solute transit through the brain parenchyma. Its dysfunction has been considered as a possible cause of idiopathic intracranial hypertension (IIH)., Methods: We enrolled participants with active IIH, treated or cured IIH, and controls. The active IIH group was divided into untreated participants with recently developed (<6 mo) and chronic (6+ mo) disease. Glymphatic function was assessed using diffusion tensor imaging along the paravascular space (DTI-ALPS) to generate an ALPS-index, hypothesized to measure glymphatic function. Participants were imaged before lumbar puncture (LP) if IIH was suspected and following LP when possible., Results: ALPS indices were higher in participants with chronically present, active IIH than in those either with recently developed IIH or control participants. ALPS-indices correlated with papilledema but did not correlate significantly with age, BMI, or intracranial pressure (ICP)., Conclusions: Our findings suggest that DTI-ALPS-indices of glymphatic function may be influenced by the chronicity of intracranial hypertension but do not support the hypothesis that glymphatic dysfunction causes IIH. Though these findings are preliminary, glymphatic imaging may be a useful radiographic biomarker in IIH., Competing Interests: The authors report no conflicts of interest., (Copyright © 2024 by North American Neuro-Ophthalmology Society.)