BDS — Buffalo Delirium Scale

What this tool is and how to interpret its evidence

The Buffalo Delirium Scale (BDS) is a nurse-completed monitoring measure developed for adults receiving home hospice care. It was designed to identify patterns that may precede delirium rather than to establish a current DSM diagnosis. The 11-item form is completed during weekly visits using observation and information from the patient, caregiver or both. Ratings reflect how often relevant changes occurred during the preceding week. In the published psychometric analysis, ten prodromal symptom-frequency items grouped into cognitive-problem, distress and sleep-problem factors; the additional form element records the clinician's delirium judgement.

Breier and colleagues analysed 4,992 ratings from 817 hospice patients. Internal consistency for the three factors and total score ranged from .66 to .82, and factor scores showed different associations with nurse ratings of dementia and delirium. These results support preliminary construct validity in that service, but they are not independent diagnostic-accuracy validation against a blinded DSM assessment.

No fixed clinical cutoff was established. The paper's use of unusually high total scores was exploratory and should not be converted into a bedside threshold. A high BDS score should prompt fuller assessment of acute change, cognition, distress, sleep and possible causes; it does not diagnose delirium. Generalisability beyond home hospice and end-of-life care remains uncertain. The primary publication should be linked for the original methods and form.