Definition

Acquired immunodeficiency syndrome (AIDS) is the final and most serious stage of the disease caused by the human immunodeficiency virus. Symptoms begin when an HIV-positive person presents a CD4-cell (also called T cell, a type of immune cell) count below 200. AIDS happens concurrently with numerous opportunistic infections and tumors that are normally associated with the HIV infection.

The most common neurological complications of AIDS involve opportunistic infections of the brain such as progressive multifocal leucoencephalopathy (PML) and meningitis, other opportunistic infections such as herpes zoster (shingles), peripheral neuropathy, depression, and...