The CNS is composed of the brain and spinal cord. The AIDS virus has been found in the fluids surrounding the CNS and is thought to affect the nerves of the central nervous system. Once in the CNS, the virus is capable of causing a variety of problems including loss of motor control, headaches, dementia; and vision, hearing, and speech impairment. The effects of CNS problems in persons with AIDS are characterized by behavioral and mental problems including a loss of muscular coordination and withdrawal from social contact.