MAYBE YOU know Sandra Bernhard from her frequent combative appearances on David Letterman's show. Or maybe you heard those "did-they-or-didn't they?" rumors about her and gal pal Madonna. Or maybe you witnessed her terrifying 1983 film debut as an obsessed fan in the prescient "King of Comedy."

Or maybe not.

Clearly, genre-busting actress, singer and stand-up social critic Bernhard has a long way to go before she becomes a Household Name. And her new movie "Without You, I'm Nothing" -- a film version of her long-running off-Broadway solo show -- certainly won't do much for her in the fame department. In this complex, prickly flick, Bernhard is taking artistic (and potentially career-destroying) risks, playing with her own persona -- and the nature of film and performance.

According to her on-screen manager, the success of Bernhard's off-Broadway hit has gone to her head, so it's time for a restorative return to her "roots" -- she books the oh-so-East Village act into the Parisian Room, a black supper club in Los Angeles. When we first see Bernhard onstage, she's singing Nina Simone's "Four Women" in African mufti that makes her look like a giant fig. Undulating before an understandably unresponsive black audience, Bernhard looks ludicrous as she intensely intones Simone's somber, prideful Afro-woman chant in her clear, "legit" voice.

But you can't quite dismiss it as a joke -- that's too easy. On some levels Bernhard seems to mean it. In fact, everything she touches is simultaneously mocked and med itated on. Though she makes fun of cause-commitment and meaningfulness in art, Bernhard's clearly dedicated to something -- she just refuses to be pinned down.

Bernhard's other pop-cultural targets include Warren Beatty, Madonna (lampooned by an imitative stripper called "Shoshanna"), Israeli folk songs, the Cosmo Girl, the gay subculture of the '70s, the Andy Warhol auction frenzy, and New York cable porn-show hostess Robin Byrd.

The act culminates in Bernhard giving the bewildered audience what they ostensibly want -- a literally in-your-face bump and grind in stars-and-stripes pasties and G-string to the Prince hit "Little Red Corvette." Her audience having abandoned her, she's left dancing naked, by and for herself. Finally, her beautiful, black on-screen alter ego scrawls a final expletive comment in lipstick on a tablecloth: Bernhard even supplies her own perverse capsule review!

Always an arch and off-putting performer, Bernhard, with director/co-writer John Boskovich, has designed a movie layered with so many distancing devices and alienating effects -- jarring genre clashes, perversely surreal production numbers, "talking heads" saying much and signifying nothing -- it's almost like they're striving to fail. Even diehard Bernhard cultists will leave scratching their heads over this one. But every viewer's head should be abuzz with ideas. WITHOUT YOU, I'M NOTHING (R) --

At the West End.