Lesser-known Parkinson’s symptoms to know following Carly Simon's diagnosis

'You're So Vain' singer Carly Simon has revealed she has been diagnosed with Parkinson's disease, opening up about the progressive neurological disorder in a new statement after months of public silence.

Simon, 81, shared her health update in a statement to ABC News explaining she had spent time processing the diagnosis before deciding to go public.

"So many people have written to me, kindly wondering about my relative silence, asking how I am and what I have been doing. The truth is, I've been learning how to live with Parkinson's disease," Simon said.

She continued, "It has taken me some time to understand the diagnosis, to adjust to it, and to decide how much I wanted to say about it publicly."

Simon added that the condition affects her differently day to day, 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."

Despite the health challenges, Simon said she has continued working on new music, including an upcoming album titled Comes in Waves Photo by John Lamparski/Getty Images)

How is Parkinson's diagnosed?

Simon explained her health issues initially appeared to stem from arthritis in both knees and one hip, which led to three joint replacement surgeries.

She said she assumed her mobility problems were simply part of the recovery process, but her condition kept deteriorating.

"But my mobility continued to worsen. I had trouble standing up from low chairs and deep couches without someone offering me an arm," she said, adding that there were periods when she could not walk without 'considerable help'.

Parkinson's is diagnosed through clinical evaluation, which includes physical and neurological exams. After what she described as an extensive evaluation at the Mayo Clinic, Simon was formally diagnosed with Parkinson's and began treatment, including medication for stiffness and other symptoms.

What are common symptoms of Parkinson's?

Parkinson's disease is a progressive neurological disorder that primarily affects movement, with an estimated 1.1 million people in the US currently living with the condition and nearly 90,000 new diagnoses each year, according to the Parkinson's Foundation.

Common symptoms include tremors, stiffness, slowed movement, and balance problems, while the disorder can also cause non-movement symptoms such as depression, anxiety, apathy, and cognitive changes.

Michael J. Fox was diagnosed with early-onset Parkinson's disease in 1991 at the age of 29. (Photo by Tommaso Boddi/WireImage)

What are the lesser-known symptoms of Parkinson's disease?

While tremors are the symptom most associated with Parkinson's, the Michael J. Fox Foundation notes the disease can bring a much wider range of effects, many of which are far less visible.

These include sleep disorders such as insomnia, daytime drowsiness and REM behavior disorder, as well as a noticeable drop in voice volume and slurred speech.

Loss of smell is also common and, for many patients, can appear as an early warning sign before a diagnosis is even made.

Other lesser-known effects include cognitive changes ranging from mild memory issues to dementia, orthostatic hypotension, which causes dizziness upon standing, and dystonia, a movement disorder marked by painful, prolonged muscle contractions.

The foundation also points to facial masking, a reduction in facial expression caused by slowed movement, alongside the fatigue and apathy Simon herself described in her statement.

Simon said one of the hardest symptoms to explain to others has been apathy. (Photo by Lester Cohen/WireImage)

Simon said one of the hardest symptoms to explain to others has been apathy.

"It is not simply sadness or laziness. It is as though the part of the brain that sends out invitations to participate in life has temporarily misplaced the guest list," she said.

The singer also revealed she was treated for basal cell carcinoma on her face during the same period, saying the surgery altered her appearance and left her more self-conscious about public appearances.

"Between my mobility issues, the Parkinson's diagnosis, the surgery, and the emotional effects of it all, withdrawing from public view was the most palatable reaction," she said.

Despite the health challenges, Simon said she has continued working on new music, including an upcoming album titled Comes in Waves, due for release on August 14.

"Working on the music gave shape to days that did not always have much shape," she said. "It reminded me that illness can change your life without becoming the whole of your life."

Simon, whose career spans more than five decades and includes two Grammy Awards and an Academy Award, closed her statement by thanking her family, friends, caregivers, and medical team, adding, "I am still very much here."