Trish Vradenburg, a television screenwriter and humorist who became a nationally known activist for Alzheimer’s research after losing her mother to the disease, an experience she chronicled in a play, “Surviving Grace,” died April 17 at her home in Washington. She was 70.

The cause was a heart attack, said her husband, George Vradenburg, a former general counsel and senior executive for CBS, Fox and AOL Time Warner. Vradenburg served at the time of her death as vice chairman, with her husband serving as chairman, of UsAgainstAlzheimer’s, an advocacy group the couple founded in 2010 with the stated goal of “ending Alzheimer’s by 2020.”

By the late 1980s, Vradenburg had screenwriting credits on “Kate & Allie,” “Designing Women” and “Family Ties,” had written magazine and newspaper humor columns and had published a romance novel, “Liberated Lady” (1986). But for her mother, Bea Lerner, “life suddenly began to unravel.”

“The phone calls started. I started hearing from Mother, and I didn’t like what I was hearing,” she recalled in a 2013 interview with The Washington Post. “My mother was a lioness, a powerhouse. … But that’s not who was calling me. I could hear her retreating, spiraling down. It just got worse. The confusion, the paranoia. The phone would ring, and I’d brace myself. My mother was no longer my mom.”

Lerner died in 1992. Vradenburg marshaled her grief – as well as her sense of humor – to write a play first titled “The Apple Doesn’t Fall …” about a TV screenwriter whose lovably if annoyingly overbearing mother fades away with Alzheimer’s.

The play opened in 1996 at New York’s Lyceum Theater and closed after one performance.

Vradenburg reworked the play and introduced it again in 2001 at the Kennedy Center’s Terrace Theater – and the next year at New York’s Union Square Theater. Audiences turned out in large numbers.