Validation of the Quick Confusion Scale for mental status screening in the emergency department

Abstract

Objective

The Mini-Mental Status Exam (MMSE) is a commonly used assessment of cognitive status; however, it has been considered somewhat unwieldy for use in the emergency department (ED). An alternate test, the Quick Confusion Scale (QCS), has been compared against the MMSE in a single centre. We hypothesised that the QCS would strongly correlate with the MMSE in the ED, but could be administered more quickly.

Methods

Trained research assistants administered both the QCS and the MMSE to a convenience sample of 666 patients and visitors in an urban academic ED. Patients were randomised as to which test would be administered first.

Results

The QCS required less time to complete than the MMSE (2.7±1.3 vs. 5.1±1.9 min, p<0.0001). Nine patients could not complete the MMSE because they could not use their hands to write and four because of vision impairment. Correlation of QCS and MMSE scores was fair, with Pearson’s r=0.61 (95% CI, 0.56–0.66).

Conclusions

The QCS can be administered more quickly than the MMSE, and is easier to administer in the ED because it does not require the subject to read, write or draw. There is a fair correlation between QCS and MMSE scores.