Dear Editor,

We have read with interest the paper of Brich et al. [1] published online in this journal on 27 November. We support the authors’ efforts to improve delirium detection in the ED setting. Their study showed moderate sensitivity and good specificity of the Nu-Desc delirium observation tool.

The authors’ conclusion, however, merits discussion. First, the Nu-Desc tool does not take inattention into account, which is—according to the Diagnostic and Statistical Manual of Mental Disorders (DSM)—the main feature of delirium. Therefore, criterion validity might be questioned [2].

Further, we disagree with the conclusion that a sensitivity of 77.8%, as found in the modified Nu-Desc, is sufficient. Other validated screening tools, incorporating a formal test for inattention, showed better performance in ED patients [3,4,5]. The months of the year backwards test, for example, is frequently used in such tools. The screening step of the mCAM-ED [5], which is the months of the year backwards test, had a sensitivity of 95% and a negative likelihood ratio of 0.06 [5]. In the majority of patients (80%), the months of the year backwards test can be applied in less than 30 s. Of note, two-step tools such as DTS/bCAM [3] and mCAM-ED [5] will stop evaluation after a negative screening, which is ideal in the ED setting.