Stroop color-word test in screening of minimal hepatic encephalopathy

Abstract

Objective To assess the application of Stroop color-word test (SCWT) for screening of minimal hepatic encephalopathy (MHE) in patients with liver cirrhosis. Methods Sixty patients aged 18-65 years with liver cirrhosis and 60 age, education level- matched healthy subjects were examined with SCWT. The SCWT indexes were compared between two groups. MHE was identified when patients had abnormal number connection test-A (NCT-A) and/or digit symbol test (DST). Results Time consuming and errors of card 2, 3, 4 and Stroop interference effects (SIE) reflecting word-interference and color-interference in SCWT were increased significantly in liver cirrhotic patients [(17.28±0.69)sec, (12.96±1.10)sec, (30.30±1.40)sec, (5.00±0.90)sec, (13.74±1.22)sec, (0.36±0.10) times, (0.50±0.11) times, (0.50±0.11) times, (5.00±0.90) times, (1.98±0.23) times, respectively] compared to those in healthy subjects [(10.18±0.57) sec, (7.68±0.39)sec, (15.68±0.33)sec, (1.94±0.37) sec, (6.56±0.70)sec, (0.02±0.02) times, (0.10±0.04)times, (0.10±0.04)times, (0.04±0.02) times, (0.20±0.08)times, respectively; t=12.95, 6.98, 8.19, 7.02, 11.91, 10.09, 8.97, 8.15, 17.94, 11.37, all P=0.00]; while there were no significant differences in time consuming and errors of card 1 between liver cirrhotic patients [(7.10±0.40)sec and (0.04±0.03) times] and healthy subjects [(6.72±0.36)sec and (0.02±0.02) times; t=1.89, 1.91, both P=0.06]. The sensitivity of word SIE, color SIE and word SIE + color SIE of SCWT for primary screening of MHE was 0.83(50/60), 0.88(53/60) and 0.98(59/60) respectively, whereas the specificity was 0.87(52/60), 0.80(48/60) and 0.83(50/60) respectively. Conclusion The SCWT may serve as a convenient, effective and reliable tool for primary screening MHE. Key words: Hepatic encephalopathy; Neuropsyehology; Psychological tests; Stoop color-word test