Television may be overrated as a trendsetter for American society. But there's no question that it knows how to spot a trend and follow it.

In the 1960s, America finally became sensitive about civil rights for blacks. Suddenly, there were prominent black characters in popular network shows like "I Spy," "Mission: Impossible," "Hogan's Heroes" and "Mod Squad," and even a few shows - "Julia," "The Bill Cosby Show" and "The Leslie Uggams Show" - in which black performers were dominant.The 1970s brought new sensitivity to women's issues in this country. On television that meant shows like "The Mary Tyler Moore Show," "Maude," "Police Woman," "Charlie's Angels," "Alice" and "One Day at a Time."

And the 1980s? Trends are sometimes difficult to pinpoint from the front lines, but in terms of social consciousness perhaps the most significant television accomplishments this decade have come in the medium's treatment of the handicapped, both dramatically and professionally.

Twenty years ago, when NBC was looking for an actor to play a wheelchair-bound detective in "Ironside," it looked no further than Raymond Burr, an actor whose principal physical problem is his passion for pasta. But when producers for CBS's "Wiseguy" were looking to cast a wheelchair-bound communications expert two years ago, they considered only actors who had real disabilities. They settled on Jim Byrnes, who lost both of his legs in a 1972 traffic accident.

The contrast is noteworthy. In a medium that has traditionally avoided characters and actors who are anything but "handsome, healthy and whole," recent portrayals of the mentally and physically disabled have been impressive both qualitatively and quantitatively. For example:

-No fewer than four prime time series - "Wiseguy," "Star Trek: The Next Generation," "TV 101" and "L.A. Law" - opened the season with handicapped characters listed among series regulars, with the characters in "Wiseguy" and "TV 101" both played by disabled actors.

-Most series have done at least one episode that focused on a handicapped character. "Beauty and the Beast" employed several deaf actors in one episode that featured about eight minutes of dialogue done completely in sign language.

-Made-for-TV movies have raised viewer awareness of handicaps ranging from Down's syndrome ("Kids Like These," which featured a number of Down's syndrome children) to deafness (CBS's recent "Bridge to Silence" featured a number of deaf actors, including Oscar-winner Marlee Matlin in her first speaking role and Tony-winner Phyllis Frelich).

-Even television commercials have become more sensitive to the handicapped, or haven't you seen the Levi's 501s ad with the kid in a wheelchair or the Crest ad with the Down's syndrome child brushing his teeth?

For Frelich, the first indication that progress was being made came while she was working on an episode of "Spenser: For Hire" a couple of years ago.

"I was playing an advice columnist," Frelich said through her signing interpreter during a press conference in Los Angeles earlier this year. "Another actress was talking to the director, and she asked why I had been cast in the role since the story had nothing at all to do with deafness.

"The director, bless his heart, had the perfect answer. He said, `That's just the point.' "

For Byrnes, that realization came during "Wiseguy's" first season. "I got a letter from this guy with no legs who couldn't believe what we were doing," Byrnes said. "He said, `I kept waiting for the twist, when the handicapped character goes nuts. Television has always implied that a person with a twisted body also has a twisted mind. Thanks for having the courage to be normal.' "

And that's just what Byrnes is trying to portray in his Lifeguard character. "Normalcy is what I'm striving for," he said. "I just want him to be a guy who has a job and does it. I don't want people to make a big deal out of it, because I don't."

Still, Byrnes is the first to acknowledge the value of having handicapped actors and characters on TV. "When it happens to you, you feel mutilated, and almost nothing can make you feel better," he said. "But I can't help but believe that when a kid who's lost a leg sees someone in a wheelchair on TV, he doesn't feel quite so alone."

Unlike Byrnes, Larry Drake, who won last season's Best Supporting Actor Emmy for his performance as "L.A. Law's" mentally handicapped Benny, does not share his character's handicap in real life. But that doesn't stop him from feeling a sense of responsibility to the handicapped community.

"I'm only retarded occasionally," he quipped, "but I'm concerned that Benny is going to become too idealized. He has to be allowed to fail occasionally. If we don't see him fail, then we're not telling the whole story, and we're not being true to those who really are developmentally disabled."

And that's important to Frelich, who considers America's deaf community "a cultural minority" that has been "used" by Hollywood's creative community for token emotional appeal.

"Yes, we've been used," she said. "And now that we're being given the opportunity, we must use them. We have to take advantage of our opportunities to communicate our feelings to the majority."

Frelich has done just that, making Hollywood headlines earlier this year when she led a protest against CBS's "The Equalizer" for using a hearing actress in an episode about a hearing-impaired woman.

"Would anybody even consider hiring a white actress to paint her face black and pretend to be black?" Frelich asked at the time. "Of course not. Then why do they do the same thing to us? Why must we be subjected to this insulting and demeaning discrimination?"

In other words, things are better for the handicapped on television. But they're not perfect. Yet.

"To be dismissed or to be overly praised are really two sides of the same coin," Frelich said. "Things are easier for us now than they used to be. But television still tends to use handicaps as a `plot problem.' I'm looking forward to the day when handicapped actors and characters are just regular people meeting regular problems."