A well-known Soviet historian says Leonid I. Brezhnev suffered "clinical death" in 1976 and was so weakened for the last six years of his rule that it was difficult for him to perform simple duties or understand what was going on around him.

Roy Medvedev, in an article published in this week's edition of the Moscow News, painted a picture of a leader in such bad health that his aides took over most of his functions."Brezhnev had the first serious problems with his health in 1969-1970," Medvedev wrote. "At the beginning of 1976, he had a clinical death. Doctors managed to revive him, but for the next three months he couldn't work, as his speech and abilities to think were impaired."

Medvedev, a frequent commentator on Soviet history, also said Brezhnev possessed no outstanding characteristics and was pushed into the country's top leadership job.

In the six years before his death on Nov. 10, 1982, Medvedev said, Brezhnev was constantly attended by a group of doctors.