A drug widely used to treat adults with AIDS appears to dramatically reverse the devastating effects of the disease on the brains of children, new research shows.

The AIDS virus frequently robs young victims of their ability to talk and walk and lowers their intelligence.The latest research shows that the drug AZT seems to bring back children's speech as well as other functions controlled by the brain.

"Functional ability returned to normal in many kids," said Dr. Philip Pizzo, who directed the study at the National Cancer Institute.

His research was presented Sunday at the opening of the Fourth International Conference on AIDS.

AZT, also known as zidovudine or Retrovir, is the only medicine routinely used to suppress the AIDS virus, called HIV. In adults, it can slow the progression of Acquired Immune Deficiency Syndrome but does not cure it.

Pizzo's findings were made unexpectedly during the testing of a portable pump to administer the drug to children. He found that among other changes, the youngsters' IQ scores rose about 15 points after they got the medicine.

"Everybody who looks at this data has to get excited," said Dr. Daniel Hoth of the U.S. National Institute of Allergy and Infectious Diseases. "We are all nervous by small numbers (f patients studied), but the data itself is very exciting."

Pizzo said that 62 percent of the patients had suffered clear neurological damage from the virus, and "in every case they were improved" after taking AZT.

The IQs of those who had obvious brain impairment rose from about 70 to 85. Among those who were judged to be mentally normal when the study began, the IQs improved from about 95 to 105, suggesting they had likely already suffered subtle mental injury from the infection.