NEW YORK – Hillary Clinton has stage-three Parkinson's disease and suffers from seizures, according to three sources who have had a personal relationship with the Democratic Party presidential nominee.

The sources, who spoke to WND on condition of anonymity, explained that her seizures or dizzy spells can be triggered by being out in the sun, such as apparently occurred Sunday when she was videoed collapsing as she was escorted into her limousine in New York City.

After the episode Sunday, the Clinton campaign announced she had been diagnosed on Friday with pneumonia.

However, images captured at the 9/11 memorial Sunday showed Clinton apparently being asked by a medical professional to squeeze her fingers, a test that would indicate she suffers from a neurological disease such as Parkinson's.

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Meanwhile, a Republican state legislator in New Hampshire said Monday he believes Clinton has Parkinson's.

Daniel Tamburello commented on his Facebook page that his father had Parkinson's, and he noted pneumonia is common among sufferers of the neuro-degenerative disease.

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As WND reported Monday, two physicians have stated they believe Clinton could have Parkinson's.

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The National Parkinson Foundation says stage three of the five stages "is considered mid-stage in the progression of the disease."

"Loss of balance and slowness of movements are hallmarks of this phase," the foundation states regarding stage three. "Falls are more common. Though the person is still fully independent, symptoms significantly impair activities of daily living such as dressing and eating."

The fourth stage is characterized by "severe and very limiting" symptoms.

"It’s possible to stand without assistance, but movement may require a walker. The person needs help with activities of daily living and is unable to live alone," according to the foundation.

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In stage five, the "most advanced and debilitating stage," the person requires a wheelchair or is bedridden, and "around-the-clock nursing care is required for all activities."

"The person may experience hallucinations and delusions," the Parkinson's foundation says.

WND also reported Monday that high-level Democrat power brokers on Wall Street and in New York City law firms and unions speaking to WND on condition their names be withheld say Clinton's health problems are causing panic among top party operatives and donors.

The top Democratic Party politicos in New York City have decided they can no longer rely on a two-page report of good health put out by the campaign, insisting it's time to replace Clinton's current medical team with A-list professionals, which are readily available in New York City.

If top medical experts conclude it's likely Clinton will suffer another fainting spell, regardless of the treatment she is given, the mood among New York Democrats is that now is the time to find a replacement.

At least eight Democrats or establishment media figures, some citing multiple party members, have raised the specter of replacing Clinton or questioned the campaign's handling of her health issues, including a former Democratic National Committee chairman.

Jerome Corsi's "Partners in Crime: The Clintons' Scheme to Monetize the White House for Personal Profit," is available only at the WND Superstore!