Grading of electroencephalographic changes in hepatic encephalopathy
| Grade | Features |
|---|---|
| A | Generalised suppression of alpha rhythm |
| B | Unstable alpha rhythm with paroxysmal waves at 5 to 7 per second; occasional underlying fast activity |
| C | Runs of medium voltage 5 to 6 per second waves bilaterally over frontal and temporal lobes; alpha rhythm seen occasionally |
| D | Constant 5 to 6 per second waves in all areas |
| E | Bilaterally synchronous, 2 to 3 per second waves, predominating over frontal lobes and spreading backward to occipital lobes; occasional short-lived appearance of faster rhythms (5 to 6 per second) |
From Parsons-Smith et al. 22