From the Guidelines
The CAM (Confusion Assessment Method) is generally considered better than the 4AT for delirium screening in most clinical settings, due to its high sensitivity and specificity, and comprehensive assessment of delirium features. The CAM has been extensively validated across various healthcare environments and is widely regarded as the gold standard tool for delirium assessment 1. It evaluates four key features: acute onset and fluctuating course, inattention, disorganized thinking, and altered level of consciousness. While the 4AT is a newer tool that offers advantages in terms of speed and simplicity, the CAM provides a more thorough assessment that can detect subtle presentations of delirium.
Some of the key advantages of the CAM include:
- High sensitivity and specificity when properly administered by trained healthcare professionals
- Comprehensive assessment of delirium features
- Widely regarded as the gold standard tool for delirium assessment
- Extensively validated across various healthcare environments
In contrast, the 4AT is a quicker and simpler tool that does not require special training, but it may not provide as comprehensive an assessment as the CAM. The choice between these tools should ultimately be guided by the specific clinical context, available resources, and staff expertise 1. However, based on the available evidence, the CAM is generally considered the better choice for delirium screening in most clinical settings.
It's worth noting that the CAM has been recommended by several guidelines, including the Critical Care Medicine guidelines, which state that ICU patients at moderate to high risk for delirium should be routinely monitored for the development of delirium using a valid and reliable delirium assessment tool, such as the CAM-ICU 1. Additionally, the British Journal of Anaesthesia recommends using a validated screening tool, such as the CAM, to monitor at-risk older surgical patients for delirium 1.
From the Research
Delirium Assessment Tools
The 4AT (Four Assessment Tool) and the CAM (Confusion Assessment Method) are two commonly used tools for assessing delirium.
- The CAM is the most widely used clinical assessment tool for the diagnosis of delirium 2.
- The 4AT has become well-established in acute care because of its good psychometric properties and practicability 3.
Comparison of 4AT and CAM
- A rapid review of available delirium assessments identified 75 delirium detection tools, with many focusing on inattention as well as acute onset and/or fluctuating course of cognitive changes as key features for delirium 3.
- The 3D-CAM, a 3-minute diagnostic assessment for CAM-defined delirium, has been derived and validated, showing high sensitivity and specificity relative to a reference standard 4.
- A comparative effectiveness study found that the 3D-CAM had substantially higher sensitivity than the CAM-ICU in hospitalized older general medicine patients, and similar administration time 5.
Limitations and Future Directions
- The results of delirium assessments may vary among raters, highlighting the need for objective tools like electroencephalography (EEG) to complement clinical assessments 6.
- EEG abnormalities are prevalent in patients with delirium, particularly in elderly patients, and CAM scores and hospitalization duration are valuable predictors of EEG abnormalities 6.