Lees R, Corbet S, Johnston C, Moffitt E, Shaw G, Quinn T. Test Accuracy of Short Screening Tests for Diagnosis of Delirium or Cognitive Impairment in an Acute Stroke Unit Setting. Stroke. 2013
Stroke survivors with cognitive dysfunction have higher mortality and delayed recovery. In the acute setting, it can be very hard to diagnose, often complicated by delirium or aphasia.
What screening tool do you use to identify cognitive deficits in your stroke patients?
|source: 4-A test|
There is no right answer. Quinn’s group performed brief cognitive screening tests in 111 consecutive ischemic and hemorrhagic stroke patients with median NIHSS 3 admitted to a single UK stroke unit. They used the MoCA as a reference standard, but were unsure where to draw the threshold for deficits (traditionally ≤26 which would mean 89% of this cohort is affected, but prior stroke publications have used ≤24 or ≤20). Using the 26 point cutoff, they found the 4 A-test had favorable sensitivity (0.86) and specificity (0.78) for cognition and actually was sensitive (1.00) and somewhat specific (0.82) for delirium when using the CAM tool as a reference standard. The other tests (clock drawing, 4-AMT, Cog-4, GCS, SQ) did not do as well at the traditional MoCA threshold. The authors’ conclusion, rightly so, was that there is no validated screening device for cognition in acute stroke and more studies are needed to find a sensitive one. Even the gold standard is unknown at this point.