The diagnosis of hepatic encephalopathy (HE) is based mostly on clinical criteria. It is important to assess the severity of HE quantitatively for both clinical practice and research; however, this remains a difficult and challenging problem. Modalities like psychometric tests, electroencephalography, evoked potentials, and several innovative biochemical indices have shown promise in this regard. No single parameter or index has yet been shown to be infallible in assessing the severity of HE.