Prevalence of abnormal psychometric tests and critical flicker frequency after clinical recovery of overt hepatic encephalopathy

Background: Abnormal psychometric tests are common in cirrhotic patients without overt encephalopathy. It may seriously impair the patient′s daily functioning and quality of life. Prevalence of abnormal psychometric tests after the clinical recovery of overt encephalopathy has not been studied.
Materials and Methods: Consecutive 80 patients (age, 44.5±9.8yr; M: F 66:14) with hepatic encephalopathy (HE) who recovered and met inclusion criteria were evaluated for abnormal psychometric tests ( > 2 SD) and critical flicker frequency (CFF < 38Hz). All patients underwent number connection tests-A and B, figure connection tests -A and B (if illiterate), digit symbol test, object assembly test, CFF and arterial ammonia after one month of clinical recovery of HE.
Results: Prevalence of abnormal psychometric tests (> 2SD) was seen in 58 (72.5%) patients. [33 (66%) of 50 patients on lactulose and 25 (83%) of 30 patients not on lactulose, P = 0.12]. Arterial ammonia was significantly higher in patients with abnormal psychometric tests compared to patients without it (86.3±22.2 vs 50.4±11.5 mmol/l, P = 0.01). CFF was < 38Hz in 50 patients (62.5%). Patients with ≥2 abnormal psychometric tests had CFF significantly lower than with normal psychometric tests (35.6±2.3 vs 40.7±2.4 Hz, P = 0.001). CFF sensitivity and specificity in diagnosing ≥2 abnormal psychometric tests was 82 and 83% respectively. CFF was significantly correlated with psychometric tests [NCT-A (-0.672, P = 0.001) and B (-0.743, P = 0.001), digit symbol test (-0.533, P = 0.001), object assembly test (-0.659, P =0.001) and arterial ammonia level (-0.385, P = 0.02)].
Conclusion: About 73% of patients who recovered from HE had abnormal psychometric tests ( > 2SD). CFF is a simple reliable tool to find out the presence of abnormal tests.