| Grade | Mental status | Asterixis | EEG |
| I | Euphoria/depression | Yes/no | Usually normal |
| Mild confusion | |||
| Slurred speech | |||
| Disordered sleep | |||
| II | Lethargy | Yes | Abnormal |
| Moderate confusion | |||
| III | Marked confusion | Yes | Abnormal |
| Incoherent | |||
| Sleeping but arousable | |||
| IV | Coma | No | Abnormal |
