Comparison of novel tools with traditional cognitive tests in detecting delirium in elderly medical patients

BACKGROUND Efficient detection of delirium and comorbid delirium-dementia is a key diagnostic challenge.Development of new,efficient delirium-focused methods of cognitive assessment is a key challenge for improved detection of neurocognitive disorders in everyday clinical practice.AIM To compare the accuracy of two novel bedside tests of attention,vigilance and visuospatial function with conventional bedside cognitive tests in identifying delirium in older hospitalized patients.METHODS 180 consecutive elderly medical inpatients(mean age 79.6±7.2;51%female)referred to a psychiatry for later life consultation-liaison service with delirium,dementia,comorbid delirium-dementia and cognitively intact controls.Participants were assessed cross-sectionally with conventional bedside cognitive tests[WORLD,Months Backward test(MBT),Spatial span,Vigilance A and B,Clock Drawing test and Interlocking Pentagons test]and two novel cognitive tests[Lighthouse test,Letter and Shape Drawing test(LSD)-4].RESULTS Neurocognitive diagnoses were delirium(n=44),dementia(n=30),comorbid delirium-dementia(n=60)and no neurocognitive disorder(n=46).All conventional tests had sensitivity of>70%for delirium,with best overall accuracy for the Vigilance-B(78.3%),Vigilance-A(77.8%)and MBT(76.7%)tests.The sustained attention component of the Lighthouse test was the most distinguishing of delirium(sensitivity 84.6%;overall accuracy 75.6%).The LSD-4 had sensitivity of 74.0%and overall accuracy 74.4%for delirium identification.Combining tests allowed for enhanced sensitivity(>90%)and overall accuracy(≥75%)with the highest overall accuracy for the combination of MBT-Vigilance A and the combined Vigilance A and B tests(both 78.3%).When analyses were repeated for those with dementia,there were similar findings with the MBTVigilance A the most accurate overall combination(80.0%).Combining the Lighthouse-SA with the LSD-4,a fail in either test had sensitivity for delirium of 91.4 with overall accuracy of 74.4%.CONCLUSION Bedside tests of attention,vigilance and visuospatial ability can help to distinguish neurocognitive disorders,including delirium,from other presentations.The Lighthouse test and the LSD-4 are novel tests with high accuracy for detecting delirium.