Phenotypes and subphenotypes of delirium: a review of current categorisations and suggestions for progression.

Delirium is a clinical syndrome occurring in heterogeneous patient populations. It affects 45-87% of critical care patients and is often associated with adverse outcomes including acquired dementia, institutionalisation, and death. Despite an exponential increase in delirium research in recent years, the pathophysiological mechanisms resulting in the clinical presentation of delirium are still hypotheses. Efforts have been made to categorise the delirium spectrum into clinically meaningful subgroups (subphenotypes), using psychomotor subtypes such as hypoactive, hyperactive, and mixed, for example, and also inflammatory and non-inflammatory delirium. Delirium remains, however, a constellation of symptoms resulting from a variety of risk factors and precipitants with currently no successful targeted pharmacological treatment. Identifying specific clinical and biological subphenotypes will greatly improve understanding of the relationship between the clinical symptoms and the putative pathways and thus risk factors, precipitants, natural history, and biological mechanism. This will facilitate risk factor mitigation, identification of potential methods for interventional studies, and informed patient and family counselling. Here, we review evidence to date and propose a framework to identify subphenotypes. Endotype identification may be done by clustering symptoms with their biological mechanism, which will facilitate research of targeted treatments. In order to achieve identification of delirium subphenotypes, the following steps must be taken: (1) robust records of symptoms must be kept at a clinical level. (2) Global collaboration must facilitate large, heterogeneous research cohorts. (3) Patients must be clustered for identification, validation, and mapping of subphenotype stability.

Clinical management of delirium: The response depends on the subtypes. An observational cohort study in 602 patients.

OBJECTIVE: The hypoactive, hyperactive, and mixed subtypes of delirium differently impact patient management and prognosis, yet the evidence remains sparse. Therefore, we examined the outcome of varying management strategies in the subtypes of delirium. METHODS: In this observational cohort study, 602 patients were managed for delirium over 20 days with the following strategies: supportive care alone or in combination with psychotropics, single, dual, or triple+ psychotropic regimens. Cox regression models were calculated for time to remission and benefit rates (BRs) of management strategies. RESULTS: Generally, the mixed subtype of delirium caused more severe and persistent delirium, and the hypoactive subtype was more persistent than the hyperactive subtype. The subtypes of delirium were similarly predictive for mortality (P = 0.697) and transfer to inpatient psychiatric care (P = 0.320). In the mixed subtype, overall, psychotropic drugs were administered more often (P = 0.016), and particularly triple+ regimens were administered more commonly compared to hypoactive delirium (P = 0.007). Patients on supportive care benefited most, whereas those on triple+ regimens did worst in terms of remission in all groups of hypoactive, hyperactive, and mixed subtypes (BR: 4.59, CI 2.01-10.48; BR: 4.59, CI 1.76-31.66; BR: 3.36, CI 1.73-6.52; all P < 0.05). SIGNIFICANCE OF RESULTS: The mixed subtype was more persistent to management than the hypoactive and hyperactive subtypes. Delirium management remains controversial and, generally, supportive care benefited patients most. Psychopharmacological management for delirium requires careful choosing of and limiting the number of psychotropics.

Delirium in the intensive care setting dependent on the Richmond Agitation and Sedation Scale (RASS): Inattention and visuo-spatial impairment as potential screening domains.

OBJECTIVE: In the intensive care setting, delirium is a common occurrence; however, the impact of the level of alertness has never been evaluated. Therefore, this study aimed to assess the delirium characteristics in the drowsy, as well as the alert and calm patient. METHOD: In this prospective cohort study, 225 intensive care patients with Richmond Agitation and Sedation Scale (RASS) scores of -1 - drowsy and 0 - alert and calm were evaluated with the Delirium Rating Scale-Revised-1998 (DRS-R-98) and the Diagnostic and Statistical Manual 4th edition text revision (DSM-IV-TR)-determined diagnosis of delirium. RESULTS: In total, 85 drowsy and 140 alert and calm patients were included. Crucial items for the correct identification of delirium were sleep-wake cycle disturbances, language abnormalities, thought process alterations, psychomotor retardation, disorientation, inattention, short- and long-term memory, as well as visuo-spatial impairment, and the temporal onset. Conversely, perceptual disturbances, delusions, affective lability, psychomotor agitation, or fluctuations were items, which identified delirium less correctly. Further, the severities of inattentiveness and visuo-spatial impairment were indicative of delirium in both alert- or calmness and drowsiness. SIGNIFICANCE OF RESULTS: The impairment in the cognitive domain, psychomotor retardation, and sleep-wake cycle disturbances correctly identified delirium irrespective of the level alertness. Further, inattentiveness and - to a lesser degree - visuo-spatial impairment could represent a specific marker for delirium in the intensive care setting meriting further evaluation.

Diagnostic Performance of Delirium Assessment Tools in Critically Ill Patients: A Systematic Review and Meta-Analysis.

BACKGROUND: Critical care nurses are in the best position to detect and monitor delirium in critically ill patients. Therefore, an optimum delirium assessment tool with strong evidence should be identified with critical care nurses to perform in the daily assessment. AIM: To evaluate and compare the diagnostic performance of delirium assessment tools in diagnosing delirium in critically ill patients. METHODS: We searched five electronic databases including the Cochrane Library, PubMed, Embase, CINAHL, and a Chinese database for eligible diagnostic studies published in English or Mandarin up to December 2018. This diagnostic test accuracy meta-analysis was limited to studies in intensive care unit (ICU) settings, using the Diagnostic and Statistical Manual of Mental Disorders (DSM) as a standard reference to test the accuracy of delirium assessment tools. Eligible studies were critically appraised by two investigators independently. The summary of evidence was conducted for pooling and comparing diagnostic accuracy by a bivariate random effects meta-analysis model. The pooled sensitivities and specificities, summary receiver operating characteristic curve (sROC), the area under the curve (AUC), and diagnostic odds ratio (DOR) were calculated and plotted. The possibility of publication bias was assessed by Deeks' funnel plot. DATA SYNTHESIS: We identified and evaluated 23 and 8 articles focused on CAM-ICU and ICDSC, respectively. The summary sensitivities of 0.85 and 0.87, and summary specificities of 0.95 and 0.91 were found for CAM-ICU and ICDSC, respectively. The AUC of the CAM-ICU was 0.96 (95% CI, 0.94-0.98), with DOR at 99 (95% CI, 55-177). The AUC of the ICDSC was 0.95 (95% CI, 0.92-0.96), and the DOR was 65 (95% CI, 27-153). LINKING EVIDENCE TO ACTION: CAM-ICU demonstrated higher diagnostic test accuracy and is recommended as the optimal delirium assessment tool. However, the results should be interpreted with caution due to the between-study heterogeneity of this diagnostic test accuracy meta-analysis.

Poststroke Delirium Clinical Motor Subtypes: The PRospective Observational POLIsh Study (PROPOLIS).

OBJECTIVE: Although delirium is the most common neurobehavioral complication after stroke, its motor subtypes-hypoactive, hyperactive, mixed, and none-as well as their risk factors are not well characterized. Motor subtypes influence recognition and prognosis of delirium in hospitalized patients. METHODS: The aim of this prospective study was to assess the frequency of poststroke delirium subtypes and to describe their predictive models. Consecutive patients with stroke were screened for delirium with the Confusion Assessment Method for the Intensive Care Unit. Delirium was diagnosed according to DSM-5 criteria, and subtypes were classified with the Delirium Motor Subtype Scale-4. Baseline demographic characteristics, biochemistry, stroke-related data, medications, neurological deficits, and premorbid cognitive and functional impairments were assessed. RESULTS: Out of 750 patients (mean age, 71.75 years [SD=13.13]), 203 (27.07%) had delirium: 85 (11.34%) were hypoactive, 77 (10.27%) were mixed hypoactive-hyperactive, 31 (4.13%) were hyperactive, and 10 (1.33%) had an unspecified type. Cognitive impairment at the time of hospital admission and spatial neglect, among other factors, were identified as the best predictors for all motor delirium subtypes. CONCLUSIONS: Screening for poststroke delirium is important because the hypoactive subtype bears the worst prognosis and is misdiagnosed the most compared with other subtypes. All identified factors for the predictive models of delirium subtypes are routinely assessed during hospital admission. Their occurrence in patients with stroke should alert the treating physician to the high risk for a particular delirium subtype.

Validation of the O3DY French Version (O3DY-F) for the Screening of Cognitive Impairment in Community Seniors in the Emergency Department.

BACKGROUND: It is recommended that older patients undergo systematic mental status screening when presenting to the emergency department (ED). However, the tools available are not necessarily adapted to the ED environment, therefore, quicker and easier tools are needed. OBJECTIVES: The purpose of this study is to validate the Ottawa 3DY-French (O3DY-F) Scale as a screening tool for delirium and cognitive impairment in a French-speaking cohort. METHOD: This multicenter prospective study was conducted in four hospitals across the province of Quebec. Inclusion criteria were: age ≥ 65 years, ED stay ≥ 8 h, awaiting admission to a care unit, and independent or semi-independent in their daily living activities. Cognitive status was assessed during the initial interview using the Telephone Interview for Cognitive Screening-modified (TICS-m) and the O3DY-F scale. Comparisons were made between the O3DY-F and the TICS-m and Confusion Assessment Method (CAM) to assess the sensitivity and specificity of the O3DY-F for the detection of cognitive impairment and delirium. RESULTS: A total of 313 patients were included in this study, 139 of which had a positive O3DY-F. When compared with the CAM, the O3DY-F had a sensitivity of 84.2% (95% confidence interval [CI] 60.4-96.6) and a specificity of 58.2% (95% CI 52.3-63.9) for the detection of prevalent delirium. The O3DY-F had a sensitivity of 76.2% (95% CI 66.7-84.8) and a specificity of 67.6% (95% CI 61.0-73.6) for cognitive impairment (defined as a TICS-m < 27). CONCLUSION: The O3DY-F is a useful and effective tool to screen for delirium and undetected cognitive impairment among a French-speaking cohort in the ED.

Delirium and cognitive impairment among older patients in Norwegian emergency departments. / Delirium og kognitiv svikt blant eldre i norske akuttmottak.

BACKGROUND: Delirium is common and underdiagnosed among patients in hospitals, and is associated with complications, increased mortality, onset of dementia and need for nursing home care. Cognitive impairment from other causes is also common among hospitalised elderly people and is a key risk factor for delirium. Since no relevant prevalence studies have been undertaken in Norwegian hospitals, we investigated the prevalence of delirium among elderly patients in Norwegian emergency departments on World Delirium Awareness Day, 14 March 2018. MATERIAL AND METHOD: We included patients ≥ 75 years who arrived in ten Norwegian emergency departments between 08:00 and 22:00 on that day. We identified delirium and cognitive impairment using the '4AT' screening tool and registered the patients' age and gender and the hospital and department to which they were admitted (internal medicine, surgery, orthopaedics, 'other'). RESULTS: Of 118 included patients, 20 (17 per cent) showed signs of delirium and 36 (30 per cent) showed signs of other forms of cognitive impairment. All hospitals and all categories of departments received patients with signs of delirium and cognitive impairment. INTERPRETATION: Delirium and other forms of cognitive impairment are both common among elderly patients in Norwegian emergency departments. Our results indicate that all hospital departments who treat elderly patients frequently observe these issues. All departments should therefore have routines to identify and deal with patients who suffer from delirium and cognitive impairment.

Incidence and Prevalence of Delirium Subtypes in an Adult ICU: A Systematic Review and Meta-Analysis.

OBJECTIVES: Use systematic review and meta-analytic methodology to estimate the pooled incidence, prevalence, and proportion of delirium cases for each delirium subtype (hypoactive, hyperactive, and mixed) in an adult ICU population. DATA SOURCES: We conducted a search of the MEDLINE, EMBASE, CINAHL, SCOPUS, Web of Science, and PsycINFO databases following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses standards from database inception until October 22, 2017, with no restrictions. STUDY SELECTION: We included original research conducted in adults admitted to any medical, surgical, or speciality ICU that reported incidence or prevalence estimates of delirium according to delirium subtype. DATA EXTRACTION: Data were extracted on sample size, population demographics, condition information, and reported delirium estimates. DATA SYNTHESIS: Forty-eight studies (27,342 patients; 4,550 with delirium) with an overall pooled prevalence of 31% (95% CI, 24-41; I = 99%) met inclusion criteria. The pooled incidence (n = 18 studies) of delirium subtypes were hyperactive (4% [95% CI, 2-6]; I = 92%]), hypoactive (11% [95% CI, 8-17; I = 97%]), and mixed (7% [95% CI, 4-11; I = 97%]). The pooled prevalence (n = 31 studies) of delirium subtypes were hyperactive (4% [95% CI, 3-6; I = 94%]), hypoactive (17% [95% CI, 13-22; I = 97%]), and mixed (10% [95% CI, 6-16; I = 99%]). The pooled prevalence of hypoactive delirium in study populations with a similarly high severity of illness or mechanically ventilated was higher (severity of illness: 29% [95% CI, 18-46%; I = 95%], 100% mechanically ventilated: 35% [95% CI, 23-55%; I = 93%]) compared with the pooled prevalence of hypoactive delirium. CONCLUSIONS: Despite significant heterogeneity between studies, these data show the majority of delirious ICU patients to have hypoactive delirium, a finding with potential monitoring, management, and prognostic implications. The prevalence of hypoactive delirium varies between-study populations and is higher in patients with greater severity of illness.

Refining Delirium: A Transtheoretical Model of Delirium Disorder with Preliminary Neurophysiologic Subtypes.

The development of delirium indicates neurophysiologic disruption and predicts unfavorable outcomes. This relationship between delirium and its outcomes has inspired a generation of studies aimed at identifying, predicting, and preventing both delirium and its associated sequelae. Despite this, evidence on delirium prevention and management remains limited. No medication is approved for the prevention or treatment of delirium or for its associated psychiatric symptoms. This unmet need for effective delirium treatment calls for a refined approach. First, we explain why a one-size-fits-all approach based on a unitary biological model of delirium has contributed to variance in delirium studies and prevents further advance in the field. Next, in parallel with the shift from dementia to "major neurocognitive disorder," we propose a transtheoretical model of "delirium disorder" composed of interactive elements-precipitant, neurophysiology, delirium phenotype, and associated psychiatric symptoms. We explore how these relate both to the biopsychosocial factors that promote healthy cognition ("procognitive factors") and to consequent neuropathologic sequelae. Finally, we outline a preliminary delirium typology of specific neurophysiologic disturbances. Our model of delirium disorder offers several avenues for novel insights and clinical advance: it univocally differentiates delirium disorder from the phenotype of delirium, highlights delirium neurophysiology as a treatment target, separates the core features of delirium from associated psychiatric symptoms, suggests how procognitive factors influence the core elements of delirium disorder, and makes intuitive predictions about how delirium disorder leads to neuropathologic sequelae and cognitive impairment. Ultimately, this model opens several avenues for modern neuroscience to unravel this disease of antiquity.

Delirium Subtypes and Associated Characteristics in Older Patients With Exacerbation of Chronic Conditions.

OBJECTIVE: The prevalence and prognosis of delirium motor subtypes are not yet well established. We analyzed the prevalence of motor subtypes of delirium, as well as their risk factors and outcomes, among older vulnerable patients admitted for short-term management of exacerbated chronic conditions. METHODS: Cohort study of patients aged 65 and older who developed delirium while admitted to a subacute care unit for 12 months (N = 352). Confusion Assessment Method was used to determine the presence of delirium and the Delirium Motor Subtype Scale was used to define the motor subtype. Outcomes included discharge destination, mortality, readmission, and functional trajectories. RESULTS: Out of 352 patients with delirium (mean age= 87.4, 73.6% with dementia), hyperactive delirium was the most prevalent subtype (40.6%), followed by mixed (31%), hypoactive (25.9%), and nonmotor (2.6%). In multivariate models, worse preadmission functional status (odds ratio [OR] [95% confidence interval {CI}] = 0.97 [0.96-0.98]) and higher comorbidity (OR [95% CI] = 1.3 [1.04-1.51]) were associated with an increased risk of hypoactive delirium. In multivariate models adjusted for different variables, including disability, hypoactive delirium was associated with mortality compared with hyperactive delirium (OR [95% CI] = 4.7 [1.6-14]) and mixed delirium (OR [95% CI] = 2.0 [1.02-3.9]) and with worse functional recovery (Beta[95% CI] = -0.2 [-12.0-(-0.4)]). CONCLUSION: Delirium motor subtypes were associated with different patient characteristics and outcomes. Hypoactive delirium seems to affect more vulnerable patients and to be associated with worse outcomes. More research on the different delirium subtypes could help develop better preventive and management strategies.

Delirium Phenotype by Age and Sex in a Pooled Data Set of Adult Patients.

The authors aimed to evaluate whether the clinical phenotype of delirium differs if dichotomized either by sex or age (cutoff age, 65 years old) in a pooled sample of 406 nondemented adult patients with delirium as defined by DSM-IV criteria. Delirium characteristics were measured with the Delirium Rating Scale-Revised-98 (DRS-R-98). DRS-R-98 items were subgrouped to represent subscores representing the three core domains of delirium (cognitive, higher-order thinking, and circadian), noncore accessory symptoms (psychotic and affective), and diagnostic characteristics (temporal onset, fluctuation, and physical disorder). The authors compared means of the DRS-R-98 subscores and medians of individual items. Exploratory factor analyses evaluated delirium characteristics for each subgroup for each of the four groups-male, female, nongeriatric, and geriatric-while taking into account active medical diagnoses. Males had higher scores on motor agitation and affective lability (behavioral), whereas females had a higher frequency of hypoactive delirium. Delirium had a two-factor structure that emerged in all four study groups, and all its core domains loaded (i.e., correlated together) onto some of these two factors and with circadian domain correlating with accessory symptoms. Although the influence of a variety of active diagnoses on delirium was small and complex, traumatic brain injury had a clear influence on cognitive domain and abrupt onset. Age had a mild influence over delirium characteristics for both males and females. In conclusion, the authors confirmed a two-factor structure for delirium phenomenology, regardless of age and sex, with few significant differences between etiological groups.

Validation of the SOS-PD scale for assessment of pediatric delirium: a multicenter study.

BACKGROUNDS: Reports of increasing incidence rates of delirium in critically ill children are reason for concern. We evaluated the measurement properties of the pediatric delirium component (PD-scale) of the Sophia Observation Withdrawal Symptoms scale Pediatric Delirium scale (SOS-PD scale). METHODS: In a multicenter prospective observational study in four Dutch pediatric ICUs (PICUs), patients aged ≥ 3 months and admitted for ≥ 48 h were assessed with the PD-scale thrice daily. Criterion validity was assessed: if the PD-scale score was ≥ 4, a child psychiatrist clinically assessed the presence or absence of PD according to the Diagnostic and statistical manual of mental disorders (DSM)-IV. In addition, the child psychiatrist assessed a randomly selected group to establish the false-negative rate. The construct validity was assessed by calculating the Pearson coefficient (rp) for correlation between the PD-scale and Cornell Assessment Pediatric Delirium (CAP-D) scores. Interrater reliability was determined by comparing paired nurse-researcher PD-scale assessments and calculating the intraclass correlation coefficient (ICC). RESULTS: Four hundred eighty-five patients with a median age of 27.0 months (IQR 8-102) were included, of whom 48 patients were diagnosed with delirium by the child psychiatrist. The PD-scale had overall sensitivity of 92.3% and specificity of 96.5% compared to the psychiatrist diagnosis for a cutoff score ≥4 points. The rp between the PD-scale and the CAP-D was 0.89 (CI 95%, 0.82-0.93; p < 0.001). The ICC of 75 paired nurse-researcher observations was 0.99 (95% CI, 0.98-0.99). CONCLUSIONS: The PD-scale has good reliability and validity for early screening of PD in critically ill children. It can be validly and reliably used by nurses to this aim.

Recommendations for the Nomenclature of Cognitive Change Associated With Anaesthesia and Surgery-2018.

Cognitive change affecting patients after anaesthesia and surgery has been recognised for more than 100 yr. Research into cognitive change after anaesthesia and surgery accelerated in the 1980s when multiple studies utilised detailed neuropsychological testing for assessment of cognitive change after cardiac surgery. This body of work consistently documented decline in cognitive function in elderly patients after anaesthesia and surgery, and cognitive changes have been identified up to 7.5 yr afterwards. Importantly, other studies have identified that the incidence of cognitive change is similar after non-cardiac surgery. Other than the inclusion of non-surgical control groups to calculate postoperative cognitive dysfunction, research into these cognitive changes in the perioperative period has been undertaken in isolation from cognitive studies in the general population. The aim of this work is to develop similar terminology to that used in cognitive classifications of the general population for use in investigations of cognitive changes after anaesthesia and surgery. A multispecialty working group followed a modified Delphi procedure with no prespecified number of rounds comprised of three face-to-face meetings followed by online editing of draft versions.Two major classification guidelines [Diagnostic and Statistical Manual for Mental Disorders, fifth edition (DSM-5) and National Institute for Aging and the Alzheimer Association (NIA-AA)] are used outside of anaesthesia and surgery, and may be useful for inclusion of biomarkers in research. For clinical purposes, it is recommended to use the DSM-5 nomenclature. The working group recommends that 'perioperative neurocognitive disorders' be used as an overarching term for cognitive impairment identified in the preoperative or postoperative period. This includes cognitive decline diagnosed before operation (described as neurocognitive disorder); any form of acute event (postoperative delirium) and cognitive decline diagnosed up to 30 days after the procedure (delayed neurocognitive recovery) and up to 12 months (postoperative neurocognitive disorder).

Recommendations for the nomenclature of cognitive change associated with anaesthesia and surgery-2018.

Cognitive change affecting patients after anaesthesia and surgery has been recognised for more than 100 yr. Research into cognitive change after anaesthesia and surgery accelerated in the 1980s when multiple studies utilised detailed neuropsychological testing for assessment of cognitive change after cardiac surgery. This body of work consistently documented decline in cognitive function in elderly patients after anaesthesia and surgery, and cognitive changes have been identified up to 7.5 yr afterwards. Importantly, other studies have identified that the incidence of cognitive change is similar after non-cardiac surgery. Other than the inclusion of non-surgical control groups to calculate postoperative cognitive dysfunction, research into these cognitive changes in the perioperative period has been undertaken in isolation from cognitive studies in the general population. The aim of this work is to develop similar terminology to that used in cognitive classifications of the general population for use in investigations of cognitive changes after anaesthesia and surgery. A multispecialty working group followed a modified Delphi procedure with no prespecified number of rounds comprised of three face-to-face meetings followed by online editing of draft versions. Two major classification guidelines [Diagnostic and Statistical Manual for Mental Disorders, fifth edition (DSM-5) and National Institute for Aging and the Alzheimer Association (NIA-AA)] are used outside of anaesthesia and surgery, and may be useful for inclusion of biomarkers in research. For clinical purposes, it is recommended to use the DSM-5 nomenclature. The working group recommends that 'perioperative neurocognitive disorders' be used as an overarching term for cognitive impairment identified in the preoperative or postoperative period. This includes cognitive decline diagnosed before operation (described as neurocognitive disorder); any form of acute event (postoperative delirium) and cognitive decline diagnosed up to 30 days after the procedure (delayed neurocognitive recovery) and up to 12 months (postoperative neurocognitive disorder).

A comparison of outcomes according to different diagnostic systems for delirium (DSM-5, DSM-IV, CAM, and DRS-R98).

ABSTRACTStudies indicate that DSM-5 criteria for delirium are relatively restrictive, and identify different cases of delirium compared with previous systems. We evaluate four outcomes of delirium (mortality, length of hospital stay, institutionalization, and cognitive improvement) in relation to delirium defined by different DSM classification systems.Prospective, longitudinal study of patients aged 70+ admitted to medical wards of a general hospital. Participants were assessed up to a maximum of four times during two weeks, using DSM-5 and DSM-IV criteria, DRS-R98 and CAM scales as proxies for DSM III-R and DSM III.Of the 200 assessed patients (mean age 81.1, SD = 6.5; and 50% female) during hospitalization, delirium was identified in 41 (20.5%) using DSM-5, 45 (22.5%) according to DSM-IV, 46 (23%) with CAM positive, and 37 (18.5%) with DRS-R98 severity score >15. Mortality was significantly associated with delirium according to any classification system, but those identified with DSM-5 were at greater risk. Length of stay was significantly longer for those with DSM-IV delirium. Discharge to a care home was associated only with DRS-R98 defined delirium. Cognitive improvement was only associated with CAM and DSM-IV. Different classification systems for delirium identify populations with different outcomes.

Subsyndromal delirium in the intensive care setting: Phenomenological characteristics and discrimination of subsyndromal delirium versus no and full-syndromal delirium.

OBJECTIVE: Similar to delirium, its subsyndromal form has been recognized as the cause of diverse adverse outcomes. Nonetheless, the nature of this subsyndromal delirium remains vastly understudied. Therefore, in the following, we evaluate the phenomenological characteristics of this syndrome versus no and full-syndromal delirium. METHOD: In this prospective cohort study, we evaluated the Delirium Rating Scale-Revised, 1998 (DRS-R-98) versus the Diagnostic and Statistical Manual of Mental Disorders, 4th ed., Text Revision (DSM-IV-TR) diagnostic criteria and examined the diagnosis of delirium with respect to phenomenological distinctions in the intensive care setting. RESULTS: Out of 289 patients, 36 with subsyndromal delirium versus 86 with full-syndromal and 167 without delirium were identified. Agreement with respect to the DSM-IV-TR diagnosis of delirium was perfect. The most common subtype in those with subsyndromal delirium was hypoactive, in contrast to mixed subtype in those with full-syndromal delirium versus no motor alterations in those without delirium. By presence and severity of delirium symptoms, subsyndromal delirium was intermediate. The ability of the DRS-R-98 items to discriminate between either form of delirium was substantial. Between subsyndromal and no delirium, the cognitive domain and sleep-wake cycle were more impaired and allowed a distinction with no delirium. Further, between full- and subsyndromal delirium, the prevalence and severity of individual DRS-R-98 items were greater. Although the differences between these two forms of delirium was substantial, the items were not very specific, indicating that the phenomenology of subsyndromal delirium is closer to full-syndromal delirium. SIGNIFICANCE OF RESULTS: Phenomenologically, subsyndromal delirium was found to be distinct from and intermediate between no delirium and full-syndromal delirium. Moreover, the greater proximity to full-syndromal delirium indicated that subsyndromal delirium represents an identifiable subform of full-syndromal delirium.

Exploring Delirium's Heterogeneity: Association Between Arousal Subtypes at Initial Presentation and 6-Month Mortality in Older Emergency Department Patients.

OBJECTIVES: To determine how delirium subtyped by level of arousal at initial presentation affects 6-month mortality. DESIGN: This was a preplanned secondary analysis of two prospective cohort studies. SETTING: Academic tertiary care emergency department (ED). PARTICIPANTS: 1,084 ED patients who were 65 years old or older. MEASUREMENTS: At the time of enrollment, trained research personnel performed the Confusion Assessment Method for the Intensive Care Unit and the Richmond Agitation Sedation Score to determine delirium and level of arousal, respectively. Patients were categorized as having no delirium, delirium with normal arousal, delirium with decreased arousal, or delirium with increased arousal. Death was ascertained by medical record review and the Social Security Death Index. Cox proportional hazard regression was used to analyze the association between delirium arousal subtypes and 6-month mortality. RESULTS: Delirium with normal arousal was the only subtype that was significantly associated with increased 6-month mortality (hazard ratio [HR]: 3.1, 95% confidence interval [CI]: 1.3-7.4) compared with the no delirium group after adjusting for confounders. The HRs for delirium with decreased and increased arousal were 1.4 (95% CI: 0.9-2.1) and 1.3 (95% CI: 0.3-5.4), respectively. CONCLUSIONS: Delirious ED patients with normal arousal at initial presentation had a threefold increased hazard of death within 6 months compared with patients without delirium. There was a trend towards increased hazard of death in delirious ED patients with decreased arousal, but this relationship did not reach statistical significance. These data suggest that subtyping delirium by arousal may have prognostic value but requires confirmation with a larger study.

Clinical Features Associated with Delirium Motor Subtypes in Older Inpatients: Results of a Multicenter Study.

OBJECTIVE: To date motor subtypes of delirium have been evaluated in single-center studies with a limited examination of the relationship between predisposing factors and motor profile of delirium. We sought to report the prevalence and clinical profile of subtypes of delirium in a multicenter study. METHODS: This is a point prevalence study nested in the "Delirium Day 2015", which included 108 acute and 12 rehabilitation wards in Italy. Delirium was detected using the 4-AT and motor subtypes were measured with the Delirium Motor Subtype Scale (DMSS). A multinomial logistic regression was used to determine the factors associated with delirium subtypes. RESULTS: Of 429 patients with delirium, the DMSS was completed in 275 (64%), classifying 21.5% of the patients with hyperactive delirium, 38.5% with hypoactive, 27.3% with mixed and 12.7% with the non-motor subtype. The 4-AT score was higher in the hyperactive subtype, similar in the hypoactive, mixed subtypes, while it was lowest in the non-motor subtype. Dementia was associated with all three delirium motor subtypes (hyperactive, OR 3.3, 95% CI: 1.2-8.7; hypoactive, OR 2.8, 95% CI: 1.2-6.5; mixed OR 2.6, 95% CI: 1.1-6.2). Atypical antipsychotics were associated with hypoactive delirium (OR 0.23, 95% CI: 0.1-0.7), while intravenous lines were associated with mixed delirium (OR 2.9, 95% CI: 1.2-6.9). CONCLUSIONS: The study shows that hypoactive delirium is the most common subtype among hospitalized older patients. Specific clinical features were associated with different delirium subtypes. The use of standardized instruments can help to characterize the phenomenology of different motor subtypes of delirium.

Electroencephalography and delirium in the postoperative period.

Delirium commonly manifests in the postoperative period as a clinical syndrome resulting from acute brain dysfunction or encephalopathy. Delirium is characterized by acute and often fluctuating changes in attention and cognition. Emergence delirium typically presents and resolves within minutes to hours after termination of general anaesthesia. Postoperative delirium hours to days after an invasive procedure can herald poor outcomes. Easily recognized when patients are hyperactive or agitated, delirium often evades diagnosis as it most frequently presents with hypoactivity and somnolence. EEG offers objective measurements to complement clinical assessment of this complex fluctuating disorder. Although EEG features of delirium in the postoperative period remain incompletely characterized, a shift of EEG power into low frequencies is a typical finding shared among encephalopathies that manifest with delirium. In aggregate, existing data suggest that serial or continuous EEG in the postoperative period facilitates monitoring of delirium development and severity and assists in detecting epileptic aetiologies. Future studies are needed to clarify the precise EEG features that can reliably predict or diagnose delirium in the postoperative period, and to provide mechanistic insights into this pathologically diverse neurological disorder.