GETTY Hillary Clinton addresses the National Baptist Convention in Kansas City yesterday

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The 68-year-old, who has repeatedly denied she is battling serious health issues, has “never recovered” from a serious blood clot in 2012 which “triggered” the degenerative disease. And she is already in the latter stages of the illness as recent “complex partial seizures” show and “extremely unlikely” to live beyond 18 months.

GETTY An exhausted Hillary Clinton boards her plane yesterday evening

We can see Hillary Clinton demonstrating problems with motor movement, with verbal communication, with forgetfulness and weakness Medical school 'professor'

The latest controversial claims purportedly come from a professor at a US medical school, who has posted them anonymously online. In a detailed 10 minute YouTube video, using brain scans, disputed medical records and slow motion clips of Mrs Clinton, the “professor” – who claims to have taught at three medical institutions – sets out the case. “Hillary Clinton is running a campaign for president knowing that she will die.” it alleges. “Patients who are diagnosed with vascular dementia are given a three to five year life expectancy. “We can see Hillary demonstrating problems with motor movement, with verbal communication, with forgetfulness and weakness. “Subcortical vascular dementia is an especially difficult form of the disease because it is affects the brain stem, which controls many of the primitive functions of our bodies."

It continues: “I have treated many patients with brain anomalies throughout my career. “I can tell you that Hillary is showing decline consistent with a progressive disease like vascular dementia. “Very few doctors are speaking out about this because they don’t want to get involved. “Hillary Clinton is sick and likely dying. I am not making this up or overstating this. This is typical of the progression of vascular dementia.” The video, which has had 30,000 views in just 24 hours, continues: “To say that nothing is wrong with Hillary is dishonest. “Her cognition and mentation are noticeably affected. “Very soon she will be cognitively unable to fulfil the office and requirements of the presidency.“

YouTube Hillary Clinton has been filmed having several episodes described as 'seizures'

Vascular dementia is caused by reduced blood supply to the brain due to diseased or damaged blood vessels – and according to the analysis, this is exactly what happened to Mrs Clinton when she suffered serious concussion four years ago. The former US Secretary of State contracted a stomach virus in December 2012. That caused sickness and dehydration, leading her to faint, fall and bang her head causing concussion. A week later, she was diagnosed with a serious blood clot in her head, which caused a blockage in a vein that drains blood from the brain. The clot – the second that Mrs Clinton has suffered – resulted in a stay in hospital and several days of treatment, forcing her to wear special glasses for several months afterwards.

According to the NHS vascular dementia is a common form of the disease that affects more than 135,000 people in the UK. It is a degenerative cognitive impairment associated with gradual death of brain cells. It's rare in anyone younger than 65. Many cases of vascular dementia start with early warning signs, including slowness of thought, difficulty with planning, language problems, attention and concentration difficulties and mood or behavioural changes.

Mrs Clinton has been filmed on a number of occasions visibly shaking and appearing to lose her train of thought. In recent weeks she has also been affected by coughing fits. The Democrat nominee has repeatedly denied claims that she has a degenerative disease and her advisers have rubbished the “medical records” used in the analysis. Her personal physician, Lisa Bardack, from Mount Sinai Health System has also insisted the documents are fake, saying they are “false, were not written by me and are not based on any medical facts."

GETTY Hillary Clinton was first forced to wear glasses to help with her concussion in 2013