HIV infection can result in impairment in the function of the brain and spinal cord, leading to disturbances in the ability to think clearly and in strength and coordination. This disorder, which has been called the AIDS dementia complex, may be due to a direct effect of HIV on the nervous system. It is known that AZT does get into the brain to some extent, where it may reduce growth of HIV. It is hoped that AZT will stabilize or improve the symptoms of the AIDS dementia complex.