Singer Carly Simon, 83, revealed that her Parkinson's disease went undetected because its symptoms mimicked the arthritis she had already been treated for, a diagnostic overlap that affects millions of Americans.
Simon shared the news in a statement distributed to multiple media outlets on July 27, explaining that she had undergone joint replacement surgeries on both knees and one hip before anyone suspected a separate, progressive neurological condition was also at work. She assumed her difficulty walking was part of a long recovery. It wasn't.
An extensive evaluation at the Mayo Clinic eventually confirmed the Parkinson's diagnosis. But by the time Simon and her family sought that evaluation, her mobility had deteriorated to the point where she sometimes could not walk without considerable help.
In her statement, Simon described a medical path that will sound familiar to many older Americans dealing with chronic pain and stiffness.
Simon told Fox News Digital:
"My health issues began with arthritis in both knees and one hip. I had all three joints replaced, and at first, I thought the difficulty I was having walking was simply part of the long recovery process."
That assumption held for a time. Then it broke down.
"Eventually, there were periods when I could not walk without considerable help. My family and I knew that something more was going on. After an extensive evaluation at Mayo Clinic, I was diagnosed with Parkinson's."
Simon did not disclose exactly when the diagnosis came. But the gap between her joint surgeries and the Parkinson's confirmation meant she spent an unknown stretch attributing a neurological disease's symptoms to a mechanical one, a confusion her doctors apparently shared, at least initially.
Dr. Guy Schwartz, a neurologist at Stony Brook Medicine in New York who specializes in Parkinson's, said Simon's experience is far from unusual. Parkinson's disease and arthritis share a cluster of overlapping symptoms: joint and limb stiffness, difficulty walking, reduced range of motion, slower movement, balance problems, pain, fatigue, and trouble with everyday tasks.
Schwartz told Fox News Digital:
"Parkinson's disease can sometimes be misdiagnosed as arthritis, and vice versa. The one main symptom that they share is difficulty with walking, some kind of impediment, limitation or disability."
The problem gets worse when a patient already carries an arthritis diagnosis, as Simon did. Schwartz said the existing condition can cloud the clinical picture entirely.
"I've definitely been challenged by individuals who come to me with these symptoms. Sometimes the examination is confounded by significant arthritis."
One reason Parkinson's hides so effectively behind arthritis: roughly a third of Parkinson's patients never develop the tremor most people associate with the disease. Without that telltale shaking, doctors are left sorting through symptoms that look identical to garden-variety joint disease.
Schwartz drew a distinction that matters. In Parkinson's, dexterity breaks down because of slowness and stiffness, a brain-driven problem. In arthritis, the limitation is mechanical: damaged joints simply cannot move through their full range. Both patients struggle with the same daily tasks, but for fundamentally different reasons. Telling the two apart in a clinic room, especially in someone who has both conditions, is genuinely difficult.
Neither Parkinson's disease nor arthritis has a single definitive diagnostic test. Both are diagnosed largely through symptoms and physical examination, a reality that leaves room for error even among experienced specialists.
Schwartz acknowledged the limitation plainly:
"It's not unusual for there to be misdiagnoses. Sometimes seeing a patient over time helps, eventually the disease declares itself, and then it's easier to make the diagnosis."
Newer tools are emerging. Specialized imaging and skin biopsy testing can now help identify Parkinson's, and Schwartz said a blood test may be on the horizon. But none of these are yet standard, and for most patients, especially those already managing arthritis, the diagnostic journey still depends on a doctor recognizing a pattern that takes time to emerge.
The Parkinson's Foundation lists several symptoms specific to Parkinson's that do not typically appear in arthritis: resting tremor, unusually small handwriting, reduced arm swing while walking, a softened voice, a mask-like facial expression, slowed movement known as bradykinesia, loss of smell, a sleep disorder called REM sleep behavior disorder, and constipation that predates movement symptoms. Any of those red flags, in a patient already diagnosed with arthritis, should prompt a closer look.
The numbers explain why this diagnostic confusion matters beyond one famous singer. Arthritis affects nearly 60 million American adults, according to the CDC. Parkinson's disease affects approximately 1.1 million, with roughly 90,000 new diagnoses each year. The overlap in age demographics, both conditions strike hardest in older adults, means a significant number of Americans are at risk of having one condition mask the other.
Simon, now 83, fits squarely in that population. And her case illustrates a broader pattern: patients and families who sense something is wrong but defer to the existing diagnosis because it seems to explain everything.
Simon's health disclosure extended beyond Parkinson's. She also underwent treatment for basal cell carcinoma, a form of skin cancer, on her face, AP News reported. The cancer treatment affected her appearance and contributed to her decision to step back from public life.
Simon described the psychological weight of managing both conditions. Newsmax reported that she spoke openly about the toll Parkinson's takes beyond physical symptoms, apathy, anxiety, and depression among them.
She put the daily reality in unsparing terms. The New York Post reported Simon saying:
"Some days I'm so tired I can't get the day moving at all. On others, it gives me a little more room to move, think, work, and feel like myself."
But Simon has not retreated entirely. She is releasing a new album of original songs titled "Comes in Waves", her first since 2008, set for an August 14 release. She framed the creative work as a lifeline during illness, saying it gave shape to her days.
Simon acknowledged the difficulty of going public:
"It's taken me some time to understand the diagnosis, to adjust to it and to decide how much I wanted to say about it publicly."
And she offered a line that carried the weight of someone who has decided not to let a diagnosis define her:
"Illness can change your life without becoming the whole of your life."
For the millions of Americans managing chronic conditions that blur into each other, arthritis pain that might be something else, stiffness that could mean more than aging, Simon's story is a reminder that a second opinion is not a luxury. Sometimes it is the diagnosis.
