Linda Ronstadt on Life After Parkinson's Stole Her Singing Voice: 'In My Mind, I Can Still Sing'

Linda Ronstadt‘s voice put her on top of the music charts for decades and won her 10 Grammys — but her career came to a devastating end when Parkinson’s disease robbed her of her singing voice.

“It’s like not having a leg or an arm, but there’s nothing I can do about it,” the “Long Long Time” singer, 73, explains in an exclusive interview with PEOPLE, featured in this week’s issue. (A documentary about her impressive career, Linda Ronstadt: The Sound of My Voice, will premiere in theaters on Friday.)

Ronstadt was officially diagnosed with Parkinson’s disease in 2013, but she lost her singing voice four years earlier.

“It felt like something was wrong, but I couldn’t tell what it was,” she says, describing the initial symptoms. “First, I thought it was my headphone mix, then I thought it was the microphone, then I thought some frequencies were just missing from my voice. It got slowly, steadily worse.”

Ronstadt struggled to make two albums as her voice worsened. The mother of two was initially told it was “nerves,” before she was diagnosed by a neurologist.

Filled with sadness, Ronstadt adjusted slowly to the loss of her instrument. In time, her mobility declined as well.

“There’s nothing I can do and I just learned how to live with it,” she says. These days, the rock icon can’t walk far and has severe back pain that keeps her mostly at home.

“I can’t sit up in a theater and it’s hard to go to a movie or an opera,” Ronstadt says. “I try to get out, but it’s about once a year.”

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In one of her less “graceful” moments, Ronstadt recalls falling just before she was supposed to present friend Dolly Parton with her MusiCares award back in February.

“Unfortunately, [Dolly] didn’t realize how disabled I was, and she came and gave me a big hug,” Ronstadt recalls. “I said, ‘Dolly, you’re going to knock me down.’ She thought I was kidding.”

Unbalanced by the hug, Ronstadt started to fall and grabbed onto the pedestal holding Parton’s award. The trophy, which was made of glass, fell to the floor and broke into pieces.

“Dolly was a good sport about it,” Ronstadt tells PEOPLE. “She said she took the pieces home.”

Though Ronstadt can no longer sing and struggles to get around, she hasn’t lost complete connection to the talent that has guided her life since she was a teenager.

Says Ronstadt, “In my mind — in my imagination — I can still sing.”

For more on Linda Ronstadt, pick up the latest issue of PEOPLE, on newsstands Friday.