DeltaScan for the Assessment of Acute Encephalopathy and Delirium in ICU and non-ICU Patients, a Prospective Cross-Sectional Multicenter Validation Study.

OBJECTIVES: To measure the diagnostic accuracy of DeltaScan: a portable real-time brain state monitor for identifying delirium, a manifestation of acute encephalopathy (AE) detectable by polymorphic delta activity (PDA) in single-channel electroencephalograms (EEGs). DESIGN: Prospective cross-sectional study. SETTING: Six Intensive Care Units (ICU's) and 17 non-ICU departments, including a psychiatric department across 10 Dutch hospitals. PARTICIPANTS: 494 patients, median age 75 (IQR:64-87), 53% male, 46% in ICUs, 29% delirious. MEASUREMENTS: DeltaScan recorded 4-minute EEGs, using an algorithm to select the first 96 seconds of artifact-free data for PDA detection. This algorithm was trained and calibrated on two independent datasets. METHODS: Initial validation of the algorithm for AE involved comparing its output with an expert EEG panel's visual inspection. The primary objective was to assess DeltaScan's accuracy in identifying delirium against a delirium expert panel's consensus. RESULTS: DeltaScan had a 99% success rate, rejecting 6 of the 494 EEG's due to artifacts. Performance showed and an Area Under the Receiver Operating Characteristic Curve (AUC) of 0.86 (95% CI: 0.83-0.90) for AE (sensitivity: 0.75, 95%CI=0.68-0.81, specificity: 0.87 95%CI=0.83-0.91. The AUC was 0.71 for delirium (95%CI=0.66-0.75, sensitivity: 0.61 95%CI=0.52-0.69, specificity: 72, 95%CI=0.67-0.77). Our validation aim was an NPV for delirium above 0.80 which proved to be 0.82 (95%CI: 0.77-0.86). Among 84 non-delirious psychiatric patients, DeltaScan differentiated delirium from other disorders with a 94% (95%CI: 87-98%) specificity. CONCLUSIONS: DeltaScan can diagnose AE at bedside and shows a clear relationship with clinical delirium. Further research is required to explore its role in predicting delirium-related outcomes.

Functional brain network and trail making test changes following major surgery and postoperative delirium: a prospective, multicentre, observational cohort study.

BACKGROUND: Delirium is a frequent complication after surgery in older adults and is associated with an increased risk of long-term cognitive impairment and dementia. Disturbances in functional brain networks were previously reported during delirium. We hypothesised that alterations in functional brain networks persist after remission of postoperative delirium and that functional brain network alterations are associated with long-term cognitive impairment. METHODS: In this prospective, multicentre, observational cohort study, we included older patients who underwent clinical assessments (including the Trail Making Test B [TMT-B]) and resting-state functional MRI (rs-fMRI) before and 3 months after elective surgery. Delirium was assessed on the first seven postoperative days. RESULTS: Of the 554 enrolled patients, 246 remained after strict motion correction, of whom 38 (16%) developed postoperative delirium. The rs-fMRI functional connectivity strength increased 3 months after surgery in the total study population (ß=0.006; 95% confidence interval [CI]: 0.001-0.011; P=0.013), but it decreased after postoperative delirium (ß=-0.015; 95% CI: -0.028 to 0.002; P=0.023). No difference in TMT-B scores was found at follow-up between patients with and without postoperative delirium. Patients with decreased functional connectivity strength declined in TMT-B scores compared with those who did not (ß=11.04; 95% CI: 0.85-21.2; P=0.034). CONCLUSIONS: Postoperative delirium was associated with decreased brain functional connectivity strength after 3 months, suggesting that delirium has a long-lasting impact on brain networks. The decreased connectivity strength was associated with significant cognitive deterioration after major surgery. CLINICAL TRIAL REGISTRATION: NCT02265263.

The Delirium Interview as a new reference standard in studies on delirium assessment tools.

BACKGROUND: The reference standard in studies on delirium assessment tools is usually based on the clinical judgment of only one delirium expert and may be concise, unstandardized, or not specified at all. This multicenter study investigated the performance of the Delirium Interview, a new reference standard for studies on delirium assessment tools allowing classification of delirium based on written reports. METHODS: We tested the diagnostic accuracy of our standardized Delirium Interview by comparing delirium assessments of the reported results with live assessments. Our reference, the live assessment, was performed by two delirium experts and one well-trained researcher who registered the results. Their delirium assessment was compared to the majority vote of three other independent delirium experts who judged the rapportage of the Delirium Interview. Our total pool consisted of 13 delirium experts with an average of 13 ± 8 years of experience. RESULTS: We included 98 patients (62% male, mean age 69 ± 12 years), of whom 56 (57%) intensive care units (ICUs) patients, 22 (39%) patients with a Richmond Agitation Sedation Scale (RASS) < 0 and 26 (27%) non-verbal assessments. The overall prevalence of delirium was 28%. The Delirium Interview had a sensitivity of 89% (95% confidence interval [CI]: 71%-98%) and specificity of 82% (95% CI: 71%-90%), compared to the diagnosis of an independent panel of two delirium experts and one researcher who examined the patients themselves. Negative and positive predictive values were 95% (95% CI: 86%-0.99%), respectively, 66% (95% CI: 49%-80%). Stratification into ICU and non-ICU patients yielded similar results. CONCLUSION: The Delirium Interview is a feasible reference method for large study cohorts evaluating delirium assessment tools since experts could assess delirium with high accuracy without seeing the patient at the bedside.