A Comparison of the Performance between the 60- and 120-Second Conditions of the Korean-Color Word Stroop Test: Color Reading (K-CWST: CR).

Background and purpose: The Korean-Color Word Stroop Test: Color Reading (K-CWST: CR) included in the Seoul Neuropsychological Screening Battery, 2nd Edition (SNSB-II) examines inhibitory control deficit. It provides normative data for both 60- and 120-second conditions, but the validity of the 60-second condition has not yet been proven. This study examined the validity of the 60-second condition by observing concordance between the performances in cognitively normal, MCI, and mild dementia groups.

Methods: There were 1,336 patients performed the SNSB-II, including the K-CWST: CR. Based on the cognitive test results, activities of daily living, and clinical interview, the patients were assigned to normal cognition (n=104), MCI (n=884), or mild dementia (n=348) groups. Abnormal performance on the K-CWST: CR was operationally defined as 1SD below the normative mean. The receiver operating characteristic curve analyses were conducted to compare the discriminability between the 60- and 120-second conditions.

Results: The percentages of abnormal performance in the MCI group were 41.5% and 42.3%, and those in the mild dementia group were 82.7% and 82.4% for the 60- and 120-second conditions, respectively. The areas under the curve for the 60- and 120-seconds were as follows; 0.80 and 0.81 in differentiating normal from MCI; 0.95 and 0.96 in normal from mild dementia; and 0.77 and 0.77 in MCI from mild dementia.

Conclusions: The 60-second condition of the K-CWST showed very similar results, not statistically different from the 120-second condition. Therefore, the 60-second condition could be used interchangeably with the 120-second condition in a clinical setting.