Electroencephalographic Measures of Delirium in the Perioperative Setting: A Systematic Review.

Postoperative delirium (POD) is frequent in older adults and is associated with adverse cognitive and functional outcomes. In the last several decades, there has been an increased interest in exploring tools that easily allow the early recognition of patients at risk of developing POD. The electroencephalogram (EEG) is a widely available tool used to understand delirium pathophysiology, and its use in the perioperative setting has grown exponentially, particularly to predict and detect POD. We performed a systematic review to investigate the use of EEG in the pre-, intra-, and postoperative settings. We identified 371 studies, and 56 met the inclusion criteria. A range of techniques was used to obtain EEG data, from limited 1-4 channel setups to complex 256-channel systems. Power spectra were often measured preoperatively, yet the outcomes were inconsistent. During surgery, the emphasis was primarily on burst suppression (BS) metrics and power spectra, with a link between the frequency and timing of BS, and POD. The EEG patterns observed in POD aligned with those noted in delirium in different contexts, suggesting a reduction in EEG activity. Further research is required to investigate preoperative EEG indicators that may predict susceptibility to delirium.

Association Between Preoperative Anemia and Cognitive Function in a Large Cohort Study of Older Patients Undergoing Elective Surgery.

BACKGROUND: The etiology of anemia has tremendous overlap with the disease states responsible for cognitive decline. We used data from a perioperative database of older adults undergoing elective surgery with anesthesia to (1) examine relationships among preoperative anemia blood markers, preoperative screeners of cognitive function, and chronic disease status; and (2) examine the relationship of these factors with operative outcomes. The primary goal of this study was to investigate the association between preoperative anemia blood markers and cognition measured by a preoperative cognitive screener. Secondary goals were to (1) examine the relationship between preoperative anemia blood markers and chronic disease states (ie, American Society of Anesthesiologists [ASA] and frailty), and (2) investigate the relationship of preoperative anemia blood markers and cognition with operative outcomes (ie, discharge disposition, 1-year mortality, number of surgical complications, length of hospital stay, and length of intensive care unit [ICU] stay). METHODS: Data were collected at the University of Florida Health Shands Presurgical Center and the Perioperative Cognitive Anesthesia Network clinic within the electronic medical record. Patients 65 years of age or older were included if they had a preoperative hemoglobin (Hgb) value and a preoperative screening. Nonparametric methods were used for bivariate analysis. Logistic regression was used for the simultaneous examination of variables associated with nonhome discharge and 1-year mortality. Primary outcomes were discharge disposition and 1-year mortality. Secondary outcomes were number of surgical complications and length of hospital and ICU stay. RESULTS: Of 14,795 patients cognitively assessed, 8643 met the inclusion criteria. Of these, 26.7% were anemic, with 16.8%, 9.5%, and 0.4% having mild, moderate, and severe anemia, respectively. The Spearman correlation coefficient [95% confidence interval, CI] between the Hgb level and the clock drawing time (CDT) was -.15 [-.17 to -.13] (P < .0001) indicating that a lower Hgb level was associated with cognitive vulnerability. Hgb was also negatively correlated with the ASA physical status classification, patient Fried Frailty Index, and hospital and ICU length of stay. In the multivariable model, age, surgical service, ASA and Fried Frailty Index significantly predicted nonhome discharge. Furthermore, age, surgical service, ASA, Fried Frailty Index, and Hgb independently predicted death within 1 year of surgery. The odds of death, adjusted for ASA, Fried Frailty, and covariates, were 2.7 times higher for those in the mild anemic group compared to those who were not anemic (odds ratio [OR], 2.7, 95% CI, [2.1-3.5]). The odds of death, adjusted for ASA, Fried Frailty, and covariates, were 3.6 times higher for those in the moderate/severe anemic group compared to those who were not anemic (OR, 3.6, 95% CI, [2.7-4.9]). CONCLUSIONS: In this first medicine study, we established relationships among anemia, preoperative markers of frailty and cognition, and chronic disease states in a large cohort of older patients undergoing elective surgery in a large tertiary medical center. We found that anemia, cognitive vulnerability, and chronic health disease states predicted death within 1 year of surgery, and that these preoperative factors negatively contribute to surgical outcomes such as time in the ICU, length of hospital stay, nonhome discharge, and 1-year mortality. The World Health Organization (WHO) and many academic medical societies have urged the adoption of patient blood management (PBM) disciplines, yet anemia is not routinely optimized as a preoperative risk factor. Given the well-defined association between preoperative anemia and postoperative morbidity and mortality, performing elective surgery on an untreated anemic patient should be considered substandard care. With established safe and effective treatment regimens, iron deficiency anemia is a modifiable preoperative risk factor that should be addressed before elective surgery.

A Network Analysis of Digital Clock Drawing for Command and Copy Conditions.

Graphomotor and time-based variables from the digital Clock Drawing Test (dCDT) characterize cognitive functions. However, no prior publications have quantified the strength of the associations between digital clock variables as they are produced. We hypothesized that analysis of the production of clock features and their interrelationships, as suggested, will differ between the command and copy test conditions. Older adults aged 65+ completed a digital clock drawing to command and copy conditions. Using a Bayesian hill-climbing algorithm and bootstrapping (10,000 samples), we derived directed acyclic graphs (DAGs) to examine network structure for command and copy dCDT variables. Although the command condition showed moderate associations between variables (µ|ßz|= 0.34) relative to the copy condition (µ|ßz| = 0.25), the copy condition network had more connections (18/18 versus 15/18 command). Network connectivity across command and copy was most influenced by five of the 18 variables. The direction of dependencies followed the order of instructions better in the command condition network. Digitally acquired clock variables relate to one another but differ in network structure when derived from command or copy conditions. Continued analyses of clock drawing production should improve understanding of quintessential normal features to aid in early neurodegenerative disease detection.

Assessment of Blood Loss during Neuroendovascular Procedures.

(1) Background: Neuroendovascular procedures have generally been considered to have minor or inconsequential blood loss. No study, however, has investigated this question. The purpose of this study is to quantify the blood loss associated with neuroendovascular procedures and identify predictors of blood loss, using hemoglobin change as a surrogate for blood loss. (2) Methods: A retrospective review of 200 consecutive endovascular procedures (diagnostic and therapeutic) at our institution from January 2020 to October 2020 was performed. Patients had to have pre- and post-operative hematocrit and hemoglobin levels recorded within 48 h of the procedure (with no intervening surgeries) for inclusion. (3) Results: The mean age of our cohort was 60.1 years and the male representation was 52.5%. The mean pre-operative hemoglobin/hematocrit was significantly lower among females compared to males (12.1/36.2 vs. 13.0/38.5, p = 0.003, p = 0.009). The mean hemoglobin decrease was 0.5 g/dL for diagnostic angiograms compared to 1.2 g/dL for endovascular interventions (p < 0.0001), and 1.0 g/dL for all procedures combined. In a multivariate linear regression analysis, pre-operative antiplatelet/anticoagulant use was associated with a statistically significant decrease in hemoglobin. (4) Conclusions: Our data support that blood loss from diagnostic angiograms is marginal. Blood loss in endovascular interventions, however, tends to be higher. Pre-operative blood antiplatelet/anticoagulant use and increasing age appear to increase bleeding risk and may require closer patient monitoring.

Caregiver Response to an Online Dementia and Caregiver Wellness Education Platform.

BACKGROUND: Web-based educational interventions are emerging as a potential solution to improve caregiver dementia knowledge and overall well-being. OBJECTIVE: To assess the feasibility of delivering a web-based intervention for dementia caregivers by examining: 1) engagement with the online platform, 2) skill implementation, and 3) changes on outcome metrics over the 30-day study period. METHODS: Enrolled participants were onboarded by a trained research coordinator and provided 24/7 access to the platform over 30 days. At study onset and completion, caregivers completed assessments of care recipient dementia severity and neuropsychiatric symptoms along with instruments which measured dementia knowledge, caregiver burden, and carer experience. RESULTS: Of 84 referrals, 60 caregivers met study inclusion criteria and 55 completed pre and post study measures. Caregivers completed an average of 8 hours of learning over the 30-day web-based intervention, with 84.4%of participants reporting using at least one skill they learned from the online platform. Eighty-nine percent of participants reported high satisfaction with the web-based educational intervention. There were small effect sizes for decreases in NPIQ neuropsychiatric symptom severity and caregiver distress scores from pre- to post-intervention. Small effect sizes were observed for changes in caregiver burden from pre- to post-intervention among caregivers who perceived their care recipient as having high global deterioration. CONCLUSION: Findings show online educational programs are feasible for informal family caregivers of dementia and have perceived value. Future studies should address caregiver response to online education in less severe versus more severe care recipients, and explore the value of caregiver online platforms in diverse caregiver samples.

Classifying Non-Dementia and Alzheimer's Disease/Vascular Dementia Patients Using Kinematic, Time-Based, and Visuospatial Parameters: The Digital Clock Drawing Test.

BACKGROUND: Advantages of digital clock drawing metrics for dementia subtype classification needs examination. OBJECTIVE: To assess how well kinematic, time-based, and visuospatial features extracted from the digital Clock Drawing Test (dCDT) can classify a combined group of Alzheimer's disease/Vascular Dementia patients versus healthy controls (HC), and classify dementia patients with Alzheimer's disease (AD) versus vascular dementia (VaD). METHODS: Healthy, community-dwelling control participants (n = 175), patients diagnosed clinically with Alzheimer's disease (n = 29), and vascular dementia (n = 27) completed the dCDT to command and copy clock drawing conditions. Thirty-seven dCDT command and 37 copy dCDT features were extracted and used with Random Forest classification models. RESULTS: When HC participants were compared to participants with dementia, optimal area under the curve was achieved using models that combined both command and copy dCDT features (AUC = 91.52%). Similarly, when AD versus VaD participants were compared, optimal area under the curve was, achieved with models that combined both command and copy features (AUC = 76.94%). Subsequent follow-up analyses of a corpus of 10 variables of interest determined using a Gini Index found that groups could be dissociated based on kinematic, time-based, and visuospatial features. CONCLUSION: The dCDT is able to operationally define graphomotor output that cannot be measured using traditional paper and pencil test administration in older health controls and participants with dementia. These data suggest that kinematic, time-based, and visuospatial behavior obtained using the dCDT may provide additional neurocognitive biomarkers that may be able to identify and tract dementia syndromes.

Normative References for Graphomotor and Latency Digital Clock Drawing Metrics for Adults Age 55 and Older: Operationalizing the Production of a Normal Appearing Clock.

BACKGROUND: Relative to the abundance of publications on dementia and clock drawing, there is limited literature operationalizing 'normal' clock production. OBJECTIVE: To operationalize subtle behavioral patterns seen in normal digital clock drawing to command and copy conditions. METHODS: From two research cohorts of cognitively-well participants age 55 plus who completed digital clock drawing to command and copy conditions (n = 430), we examined variables operationalizing clock face construction, digit placement, clock hand construction, and a variety of time-based, latency measures. Data are stratified by age, education, handedness, and number anchoring. RESULTS: Normative data are provided in supplementary tables. Typical errors reported in clock research with dementia were largely absent. Adults age 55 plus produce symmetric clock faces with one stroke, with minimal overshoot and digit misplacement, and hands with expected hour hand to minute hand ratio. Data suggest digitally acquired graphomotor and latency differences based on handedness, age, education, and anchoring. CONCLUSION: Data provide useful benchmarks from which to assess digital clock drawing performance in Alzheimer's disease and related dementias.

Proof of concept: digital clock drawing behaviors prior to transcatheter aortic valve replacement may predict length of hospital stay and cost of care.

AIMS: Reduced pre-operative cognitive functioning in older adults is a risk factor for postoperative complications, but it is unknown if preoperative digitally-acquired clock drawing test (CDT) cognitive screening variables, which allow for more nuanced examination of patient performance, may predict lengthier hospital stay and greater cost of hospital care. This issue is particularly relevant for older adults undergoing transcatheter aortic valve replacement (TAVR), as this surgical procedure is chosen for intermediate-risk older adults needing aortic replacement. This proof of concept research explored if specific latency and graphomotor variables indicative of planning from digitally-acquired command and copy clock drawing would predict post-TAVR duration and cost of hospitalization, over and above age, education, American Society of Anesthesiologists (ASA) physical status classification score, and frailty. METHODS: Form January 2018 to December 2019, 162 out of 190 individuals electing TAVR completed digital clock drawing as part of a hospital wide cognitive screening program. Separate hierarchical regressions were computed for the command and copy conditions of the CDT and assessed how a-priori selected clock drawing metrics (total time to completion, ideal digit placement difference, and hour hand distance from center; included within the same block) incrementally predicted outcome, as measured by R2 change significance values. RESULTS: Above and beyond age, education, ASA physical status classification score, and frailty, only digitally-acquired CDT copy performance explained significant variance for length of hospital stay (9.5%) and cost of care (8.9%). CONCLUSIONS: Digital variables from clock copy condition provided predictive value over common demographic and comorbidity variables. We hypothesize this is due to the sensitivity of the copy condition to executive dysfunction, as has been shown in previous studies for subtypes of cognitive impairment. Individuals undergoing TAVR procedures are often frail and executively compromised due to their cerebrovascular disease. We encourage additional research on the value of digitally-acquired clock drawing within different surgery types. Type of cognitive impairment and the value of digitally-acquired CDT command and copy parameters in other surgeries remain unknown.

Phenotyping Cognitive Impairment using Graphomotor and Latency Features in Digital Clock Drawing Test.

The Clock Drawing Test, where the participant is asked to draw a clock from memory and copy a model clock, is widely used for screening of cognitive impairment. The digital version of the clock test, the digital clock drawing test (dCDT), employs accelerometer and pressure sensors of a digital pen to capture time and pressure information from a participant's performance in a granular digital format. While visual features of the clock drawing test have previously been studied, little is known about the relationship between demographic and cognitive impairment characteristics with dCDT latency and graphomotor features. Here, we examine dCDT feature clusters with respect to sociodemographic and cognitive impairment outcomes. Our results show that the clusters are not significantly different in terms of age and gender, but did significantly differ in terms of education, Mini-Mental State Exam scores, and cognitive impairment diagnoses.This study shows that features extracted from digital clock drawings can provide important information regarding cognitive reserve and cognitive impairments.

Cognitive Correlates of Digital Clock Drawing Metrics in Older Adults with and without Mild Cognitive Impairment.

BACKGROUND: A digital version of the clock drawing test (dCDT) provides new latency and graphomotor behavioral measurements. These variables have yet to be validated with external neuropsychological domains in non-demented adults. OBJECTIVE: The current investigation reports on cognitive constructs associated with selected dCDT latency and graphomotor variables and compares performances between individuals with mild cognitive impairment (MCI) and non-MCI peers. METHODS: 202 non-demented older adults (age 68.79 ± 6.18, 46% female, education years 16.02 ± 2.70) completed the dCDT and a comprehensive neuropsychological protocol. dCDT variables of interest included: total completion time (TCT), pre-first hand latency (PFHL), post-clock face latency (PCFL), and clock face area (CFA). We also explored variables of percent time drawing (i.e., 'ink time') versus percent time not drawing (i.e., 'think time'). Neuropsychological domains of interest included processing speed, working memory, language, and declarative memory. RESULTS: Adjusting for age and premorbid cognitive reserve metrics, command TCT positively correlated with multiple cognitive domains; PFHL and PCFL negatively associated with worse performance on working memory and processing speed tests. For Copy, TCT, PCFL, and PFHL negatively correlated with processing speed, and CFA negatively correlated with language. Between-group analyses show MCI participants generated slower command TCT, produced smaller CFA, and required more command 'think' (% Think) than 'ink' (% Ink) time. CONCLUSION: Command dCDT variables of interest were primarily processing speed and working memory dependent. MCI participants showed dCDT differences relative to non-MCI peers, suggesting the dCDT may assist with classification. Results document cognitive construct validation to digital metrics of clock drawing.

Feasibility and Rationale for Incorporating Frailty and Cognitive Screening Protocols in a Preoperative Anesthesia Clinic.

BACKGROUND: Advanced age, frailty, low education level, and impaired cognition are generally reported to be associated with postoperative cognitive complications. To translate research findings into hospital-wide preoperative assessment clinical practice, we examined the feasibility of implementing a preoperative frailty and cognitive assessment for all older adults electing surgical procedures in a tertiary medical center. We examined associations among age, education, frailty, and comorbidity with the clock and 3-word memory scores, estimated the prevalence of mild to major cognitive impairment in the presurgical sample, and examined factors related to hospital length of stay. METHODS: Medical staff screened adults ≥65 years of age for frailty, general cognition (via the clock-drawing test command and copy, 3-word memory test), and obtained years of education. Feasibility was studied in 2 phases: (1) a pilot phase involving 4 advanced nurse practitioners and (2) a 2-month implementation phase involving all preoperative staff. We tracked sources of missing data, investigated associations of study variables with measures of cognition, and used 2 approaches to estimate the likelihood of dementia in our sample (ie, using extant data and logistic regression modeling and using Mini-Cog cut scores). We explored which protocol variables related to hospital length of stay. RESULTS: The final implementation phase sample included 678 patients. Clock and 3-word memory scores were significantly associated with age, frailty, and education. Education, clock scores, and 3-word scores were not significantly different by surgery type. Likelihood of preoperative cognitive impairment was approximately 20%, with no difference by surgery type. Length of stay was significantly associated with preoperative comorbidity and performance on the clock copy condition. CONCLUSIONS: Frailty and cognitive screening protocols are feasible and provide information for perioperative care planning. Challenges to clinical adaptation include staff training, missing data, and additional administration time. These challenges appear minimal relative to the benefits of identifying frailty and cognitive impairment in a group at risk for negative postoperative cognitive outcome.

Considerations for Clock Drawing Scoring Systems in Perioperative Anesthesia Settings.

The Clock Drawing Test is a cognitive screening tool gaining popularity in the perioperative setting. We compared 3 common scoring systems: (1) the Montreal Cognitive Assessment; (2) the Mini-Cog; and (3) the Libon scale. Three novice raters acquired interrater and intrarater reliability for each scoring system and then scored 738 preoperative clock drawings with each scoring system. Final scores correlated with each other but with notable discrepancies, indicating the need to attend to interrater and intrarater reliability when implementing any scoring approach in a clinical setting.