An evaluation of single question delirium screening tools in older emergency department patients

Objectives: To determine the diagnostic performances of several single question delirium screens. To the patient we asked: "Have you had any difficulty thinking clearly lately?" To the patient's surrogate, we asked: "Is the patient at his or her baseline mental status?" and "Have you noticed the patient's mental status fluctuate throughout the course of the day?"

Methods: This was a prospective observational study that enrolled English speaking patients 65 years or older. A research assistant (RA) and emergency physician (EP) independently asked the patient and surrogate the single question delirium screens. The reference standard for delirium was a consultation-liaison psychiatrist's assessment using Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision (DSM-IV-TR) criteria. All assessments were performed within 3 h and were all blinded to each other.

Results: Of the 406 patients enrolled, 50 (12%) were delirious. A patient who was unable to answer the question "Have you had any difficulty thinking clearly lately?" was 99.7% (95% CI: 98.0%-99.9%) specific, but only 24.0% (95% CI: 14.3%-37.4%) sensitive for delirium when asked by the RA. The baseline mental status surrogate question was 77.1% (95% CI: 61.0%-87.9%) sensitive and 87.5% (95% CI: 82.8%-91.1%) specific for delirium when asked by the RA. The fluctuating course surrogate question was 77.1% (95% CI: 61.0%-87.9%) sensitive and 80.2% (95% CI: 74.8%-84.7%) specific. When asked by the EP, the single question delirium screens' diagnostic performances were similar.

Conclusions: The patient and surrogate single question delirium assessments may be useful for delirium screening in the ED.