Objectives: Delirium in the ICU is associated with poor outcomes
but is under-detected. Here we evaluated performance of a novel,
graded test for objectively detecting inattention in delirium, implemented
on a custom-built computerized device (Edinburgh Delirium
Test Box–ICU).
Design: A pilot study was conducted, followed by a prospective
case-control study.
Setting: Royal Infirmary of Edinburgh General ICU.
Patients: A pilot study was conducted in an opportunistic sample
of 20 patients. This was followed by a validation study in
30 selected patients with and without delirium (median age,
63 yr; range, 23–84) who were assessed with the Edinburgh
Delirium Test Box–ICU on up to 5 separate days. Presence
of delirium was assessed using the Confusion Assessment
Method for the ICU.
Measurements and Main Results: The Edinburgh Delirium Test
Box–ICU involves a behavioral assessment and a computerized
test of attention, requiring patients to count slowly presented
lights. Thirty patients were assessed a total of 79 times (n = 31, 23,
15, 8, and 2 for subsequent assessments; 38% delirious). Edinburgh
Delirium Test Box–ICU scores (range, 0–11) were lower
for patients with delirium than those without at the first (median, 0
vs 9.5), second (median, 3.5 vs 9), and third (median, 0 vs 10.5)
assessments (all p < 0.001). An Edinburgh Delirium Test Box–ICU
score less than or equal to 5 was 100% sensitive and 92% specific
to delirium across assessments. Longitudinally, participants’
Edinburgh Delirium Test Box–ICU performance was associated
with delirium status.
Conclusions: These findings suggest that the Edinburgh Delirium
Test Box–ICU has diagnostic utility in detecting ICU delirium
in patients with Richmond Agitation and Sedation Scale Score
greater than –3. The Edinburgh Delirium Test Box–ICU has potential
additional value in longitudinally tracking attentional deficits
because it provides a range of scores and is sensitive to change
