Delirium is highly prevalent in critical care, especially among elderly patients and individuals with dementia. Although rates vary widely across studies, findings suggest delirium affects more than 15% of hospitalized patients.1 Researchers have found that delirium strongly predicts falls, rates of mortality and medical complications, long-term cognitive dysfunction, and other adverse outcomes.1,2

However, delirium is missed or misdiagnosed in at least two-thirds of cases that present to the emergency department and other medical settings.1 Time constraints and inadequate training are among the many reasons cited for this low rate of detection. “Because formal psychiatric assessment for delirium diagnosis takes considerable time, guidelines and pathways advocate the use of brief assessment tools for delirium detection,” including the commonly used 4 A’s Test (4AT) and the short form of the Confusion Assessment Method (CAM), according to a multicenter prospective study published in in BMC Medicine.1

The 4AT contains 4 items (Alertness, Abbreviated Mental Test-4, Attention [Months Backwards test], and Acute change or fluctuating course), and a score of ≥4 (in a range of 0-12) indicates the possible presence of delirium. The test takes approximately 2 minutes to complete and does not require formal training to administer.

Continue Reading

The short-form CAM includes cognitive testing, an interview, and a 4-item algorithm: acute onset and fluctuating course, inattention, disorganized thinking, and altered level of consciousness. Positive scores on the first 2 items and at least 1 of the other 2 items indicates the presence of delirium. Administration of the CAM requires special training and takes up to 10 minutes to complete.

The study compared the utility of the 4AT to that of the CAM among patients aged ≥70 years who were admitted to emergency departments or acute medical wards at several sites in the United Kingdom. Patients underwent a reference standard assessment for delirium and either the 4AT or the CAM.

On the basis of each assessment, the prevalence of delirium was 12.1%, 14.3%, and 4.7%, respectively. The 4AT demonstrated a sensitivity of 76% (95% CI, 61%-87%) and a specificity of 94% (95% CI, 92%-97%) compared with 40% (95% CI, 26%-57%) and 100% (95% CI, 98%-100%) for the CAM.

Given its brevity (<2 minutes), lack of formal training requirement, and comparability to performance using CAM, the 4AT can “reasonably be used as an assessment tool for delirium, particularly in clinical settings in which there is a limited time, and in which staff involved in delirium detection cannot undergo the substantial special training required for use of the CAM,” the authors concluded.1

A 2018 study evaluated a newer screening tool, the Stanford Proxy Test for Delirium, a brief assessment designed to be administered by nurses.3 The Stanford Proxy Test for Delirium detected delirium in 25% of patients, whereas 26% of patients were found to have delirium based on a Diagnostic and Statistical Manual of Mental Disorders-based neuropsychiatric exam. The sensitivity and specificity of the Stanford Proxy Test for Delirium were 82.7% and 95.3%, respectively, with similar results observed in intensive care unit and general inpatient wards.

Overall, these results indicate that brief assessment tools may help to improve rates of delirium detection.

The aim is to “improve the diagnosis of delirium, with the assumption that the sooner we recognize it, the sooner we can implement corrective interventions directed at shortening its course, and thus improve outcomes,” Jose R. Maldonado, MD, FAPM, medical director of psychosomatic medicine and chief of psychiatric emergency services and transplant psychiatry at Stanford University Medical Center, told Neurology Advisor. However, the “ultimate goal is to find and predict those patients at risk for developing delirium and thus, either avoid treatments that may trigger delirium, such as benzodiazepine or opioid use, or implement corrective measures directed at preventing its development altogether.”

For additional discussion regarding this topic, Neurology Advisor interviewed Leopoldo Pozuelo, MD, MBA, FACP, FACLP, clinical vice chair of psychiatry and psychology at the Cleveland Clinic.

Related Articles

Neurology Advisor: What are the reasons why delirium is often not detected in acute settings?

Dr Pozuelo: One key reason is the lack of a daily screening tool for delirium: clinicians are horrible at detecting delirium on their own. Screening tools have been one of the key successful drivers of delirium awareness and management. Another need is to teach about delirium during clinician and nursing training, as this prompts lifelong delirium awareness and scrutiny for effective interventions.

Neurology Advisor: What are the risks associated with delayed treatment of delirium?

Dr Pozuelo: One of the biggest concerns is the prolonged neurocognitive deficits that patients incur after experiencing delirium in the hospital. Data from Vanderbilt University published in the New England Journal of Medicine in 2013 really highlighted the lingering effects of delirium months down the road.4 This fact is really becoming the key elevator speech as to why screening and treatment for delirium are important. Distress among patients and caregivers, prolonged length of hospital stay, and increased morbidity are additional risks associated with delays in recognition and treatment of delirium.

Neurology Advisor: What are some ways in which delirium detection and treatment can be improved?

Dr Pozuelo: In addition to using a screening tool, track delirium detection rates and hold teams accountable. Implement targeted rounding on patients with delirium or at risk for delirium, as well as early mobilization of these patients.

Neurology Advisor: What are remaining needs in this area in terms of research, education, or advocacy?

Dr Pozuelo: A positive step has been the acceptance that delirium is an “acute brain failure.”5 In addition, delirium should be viewed as a “team sport” that involves nursing, clinicians, physical therapists, and specialists.

We need continued studies into the mechanistic pathways that lead to and cause delirium. This will lead to more tailored and effective treatments. There is also a need for evidence-based studies focused on delirium treatments.

Global education about delirium among patients, families, caregivers, and clinicians is continuously needed. Finally, medical societies, such as the American Delirium Society and individual specialty societies, should continue to advocate for comprehensive delirium management programs.


1. Shenkin SD, Fox C, Godfrey M, et al. Delirium detection in older acute medical inpatients: a multicentre prospective comparative diagnostic test accuracy study of the 4AT and the confusion assessment method. BMC Med. 2019;17(1):138.

2. Girard TD, Jackson JC, Pandharipande PP, et al. Delirium as a predictor of long-term cognitive impairment in survivors of critical illness. Crit Care Med. 2010;38(7):1513-1520.

3. Alosaimi FD, Alghamdi A, Alsuhaibani R, et al. Validation of the Stanford Proxy Test for Delirium (S-PTD) among critical and noncritical patients. J Psychosom Res. 2018;114:8-14.

4. Pandharipande PP, Girard TD, Jackson JC, et al. Long-term cognitive impairment after critical illness. N Engl J Med. 2013;369(14):1306-1316.

5. Maldonado JR. Acute brain failure. Pathophysiology, diagnosis, management, and sequelae of delirium.Crit Care Clin. 2017;33(3):461-519.

This article originally appeared on Neurology Advisor