Electroencephalography shows no clear abnormalities in stage 0, even if minimal HE is present; in stages I, II and III there are triphasic waves over the frontal lobes that oscillate at 5 Hz, and in stage IV there is slow delta wave activity. However, the changes in EEG are not typical enough to be useful in distinguishing hepatic encephalopathy from other conditions.Once the diagnosis of encephalopathy has been made, efforts are made to exclude underlying causes (such as listed above in "causes"). This requires blood tests (urea and electrolytes, full blood count, liver function tests), usually a chest X-ray, and urinalysis. If there is ascites, a diagnostic paracentesis (removal of a fluid sample with a needle) may be required to identify spontaneous bacterial peritonitis (SBP). Classification
West Haven criteria
The severity of hepatic encephalopathy is graded with the West Haven Criteria; this is based on the level of impairment of autonomy, changes in consciousness, intellectual function, behavior, and dependence on therapy. Grade 0 - No obvious changes other than a potentially mild decrease in intellectual ability and coordination
Grade 1 - Trivial lack of awareness; euphoria or anxiety; shortened attention span; impaired performance of addition or subtraction
Grade 2 - Lethargy or apathy; minimal disorientation for time or place; subtle personality change; inappropriate behaviour
Grade 3 - Somnolence to semistupor, but responsive to verbal stimuli; confusion; gross disorientation
Grade 4 - Coma

Types
A classification of hepatic encephalopathy was introduced at the World Congress of Gastroenterology 1998 in Vienna.
Melphalan, sold under the brand name Alkeran among others, is a chemotherapy medication used to treat multiple myeloma, ovarian cancer, melanoma, and AL amyloidosis. It is taken by mouth or by injection into a vein.Common side effects include nausea and bone marrow suppression. Other severe side effects may include anaphylaxis and the development of other cancers. Use during pregnancy may result in harm to the fetus. Melphalan belongs to the class of nitrogen mustard alkylating agents. It works by interfering with the creation of DNA and RNA.Melphalan was approved for medical use in the United States in 1964. It is on the World Health Organizations List of Essential Medicines. It is available as a generic medication. Medical uses
It is used to treat multiple myeloma, ovarian cancer, AL amyloidosis, and occasionally malignant melanoma. The agent was first investigated as a possible drug for use in melanoma, it was not found to be effective.In 2016, it was approved in the U.S. for:

use as a high-dose conditioning treatment prior to hematopoietic progenitor (stem) cell transplantation in multiple myeloma (MM) patients
the palliative treatment of MM patients for whom oral therapy is not appropriateMelphalan is used to treat ocular retinoblastoma, a pediatric solid tumor. This is accomplished via transarterial catheter based slow pulsed infusion into the ophthalmic artery.