Federal health researchers tracking a dramatic rise in reported deaths from Alzheimer's disease say more awareness of the malady, rather than a sharp rise in its incidence, is the main reason.

"It's a little difficult to believe that the number of people with Alzheimer disease could increase 950 percent in eight years," said Dr. Richard Sun, an epidemiologist at the U.S. Centers for Disease Control in Atlanta."Our general feeling is heightened awareness was a little more important" Sun said Thursday.

The CDC said in its weekly report that 11,311 people, or 4.2 per 100,000 population, died from Alzheimer's disease in 1987. In 1979, the first year of a CDC study, 857 deaths, or 0.4 per 100,000, were attributed to the disease.

For the entire 1979-87 period, Alzheimer's disease was listed as the underlying cause of death for 46,202 people in the United States.

Alzheimer's disease tends to strike older people, and because the U.S. population is aging it is likely that incidence of the disease also is up - though not as much as the death rate increase, Sun said.

He said there currently is no definitive study of how many people have Alzheimer's.

The disease, characterized by progressive mental deterioration, first was recognized in the early 1900s. But public awareness of the disease was fairly limited until the 1970s.

Doctors then, Sun said, "realized that Alzheimer disease was a specific disease . . . and not a normal process of aging. There was something different about people with Alzheimer disease."

The disease has gotten much media attention in the past 10 years, with television devoting prime time programs to it and national magazines featuring Alzheimer's on cover stories.