Focusing on Inattention: The Diagnostic Accuracy of Brief Measures of Inattention for Detecting Delirium.

backgroundDelirium is frequently missed in most clinical settings. Brief delirium assessments are needed.

objectiveTo determine the diagnostic accuracy of reciting the months of year backwards (MOTYB) from December to July (MOTYB-6) and December to January (MOTYB-12) for delirium as diagnosed by a psychiatrist and to explore the diagnostic accuracies of the following other brief attention tasks: (1) spell the word "LUNCH" backwards, (2) recite the days of the week backwards, (3) 10-letter vigilance "A" task, and (4) 5 picture recognition task.

designPreplanned secondary analysis of a prospective observational study.

settingEmergency department located within an academic, tertiary care hospital.

participants234 acutely ill patients who were =65 years old. MEASUREMENTS: The inattention tasks were administered by a physician. The reference standard for delirium was a comprehensive psychiatrist assessment using Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision criteria. Sensitivities and specificities were calculated.

resultsMaking any error on the MOTYB-6 task had a sensitivity of 80.0% (95% confidence interval [CI], 60.9%-91.1%) and specificity of 57.1% (95% CI, 50.4%- 63.7%). Making any error on the MOTYB-12 task had a sensitivity of 84.0% (95% CI, 65.4%-93.6%) and specificity of 51.9% (95% CI, 45.2%-58.5%). The best combination of sensitivity and specificity was reciting the days of the week backwards task; if the patient made any error, this was 84.0% (95% CI, 65.4%-93.6%) sensitive and 81.9% (95% CI, 76.1%-86.5%) specific.

conclusionsMOTYB-6 and MOTYB-12 had very good sensitivities but had modest specificities for delirium, limiting their use as a standalone assessment. Reciting the days of the week backwards appeared to have the best combination of sensitivity and specificity for delirium.