The early signs of Parkinson’s – and how fast it can progress

While the White House deny Joe Biden has Parkinson’s, both cognitive decline and falls can be symptoms. Here’s what to watch out for

Joe Biden’s press secretary has been forced to deny that the US president is being treated for Parkinson’s disease after revelations emerged that neurologist Dr Kevin Cannard, a specialist in the disease, had visited the White House on eight separate occasions in the past year.
It follows speculation about the state of 81-year-old Biden’s cognition, which is threatening to be a potentially decisive weakness in the run-up to this autumn’s presidential election. Biden has struggled with memory lapses in recent years, appearing to lose his train of thought during last month’s debate with Donald Trump, as well as tripping and stumbling on multiple occasions during public appearances.
While there are no suggestions that Biden has Parkinson’s, both cognitive decline and falls can be symptoms of the disease, a neurodegenerative condition which progresses over the course of years and sometimes even decades.
So what are the key signs of Parkinson’s, a condition which has been described as the fastest growing neurodegenerative disease in the world due to its rapidly rising prevalence, and how does it progress?
While most people commonly perceive Parkinson’s as being characterised by tremors, there are more than 40 different symptoms of the disease. In fact, research has shown that other symptoms such as hearing or smell deficits, can be some of the earliest indications. “The first signs are usually non-movement related,” says K Ray Chaudhuri, a professor of movement disorders and neurology at King’s College London. “This includes reduced or loss of sense of smell, a sleep disorder called rapid eye movement behaviour disorder (RBD) or severe bouts of depression in some.”
Patients can also experience limb stiffness, making them more prone to falling. One study found over a third of Parkinson’s patients also reported visual hallucinations, double vision and difficulty estimating spatial relations. As Parkinson’s progresses, it can be accompanied by cognitive decline. “It’s a brain and system-wise disorder,” says David Dexter, a professor of neuropharmacology at Imperial College London and director of research for the charity Parkinson’s UK. “Even before you see any motor deficits, you can see depression and anxiety. There’s also a real problem with sleep and that can impact the problem.”
The underlying cause of Parkinson’s is a toxic form of a protein called alpha-synuclein which accumulates inside brain neurons, responsible for producing a critical brain chemical called dopamine, which plays a role in a wide range of functions from memory to mood and movement. These cells lie in a part of the midbrain called the substantia nigra, which is responsible for motor control.
This toxic protein aggregation causes progressive cell death, and by the time most people are officially diagnosed with Parkinson’s, they have already lost 60 to 80 per cent of the dopamine producing cells.
According to Parkinson’s UK, the typical age of diagnosis is over the age of 70. “It’s accelerated by ageing as we all lose dopamine as we age,” says Prof Chaudhuri, who last month helped launch the King’s Parkinson’s Charitable Fund.
The usual rate of progression is typically slow, with motor symptoms and difficulty with balance and falls only starting to become an issue in the five to 10 years after patients have been diagnosed.
“Parkinson’s is a fluctuating condition that is different for everyone, so how it progresses is very individual,” says Dr Rowan Wathes, an associate director of policy and health strategy at Parkinson’s UK. “Generally though, the decline is quite slow and happens over many years. Some people can seem to experience less notable decline, but it’s important to also remember that Parkinson’s symptoms are not always visible.”
Anxiety is one of the common symptoms of the brain changes induced by Parkinson’s and Dr Wathes says that one of the most important things for anyone living with the disease, is to try and reduce stress as much as possible. “Stress can make managing Parkinson’s more difficult and increase the appearance of symptoms like tremor,” she says. “Likewise, stress can adversely affect sleep quality and duration, while sleep problems – a common symptom of Parkinson’s – can sometimes increase stress levels.”
At the same time, Dr Wathes emphasises that it is perfectly possible to continue working in some form, for many years, even if you need to reduce your hours. While Jeremy Paxman revealed that he had been diagnosed with the disease in 2021, the veteran broadcaster has continued to work in various formats, presenting a much-lauded ITV documentary on Parkinson’s and recording the Movers and Shakers podcast about life with Parkinson’s. 
During this year’s Glastonbury festival, the actor Michael J Fox, who was diagnosed with Parkinson’s in 1991, received a rapturous reception when he joined Coldplay as a guest artist on the Pyramid Stage, playing guitar for two tracks.
Research has also increasingly suggested that various lifestyle interventions such as regular physical activity – clinical trials have found that group ballet exercises can help slow down Parkinson’s – or even taking probiotics, can help people live well with Parkinson’s for longer. Chaudhuri is encouraged by results from a trial of the liquid probiotic Symprove showing that it may help Parkinson’s patients.
At present, the primary treatment offered to Parkinson’s patients is a drug called levodopa, a medication which is absorbed by the nerve cells in the brain and boosts the levels of dopamine, as a way of relieving the tremors and various motor symptoms. Other drugs known as dopamine agonists can be used in a similar manner.
Some of the initial effects of levodopa can be dramatic, particularly when it comes to alleviating tremors and other motor symptoms, but it does not alter the disease course and ultimately these symptoms return.
However, a whole array of newer treatments are in the pipeline. Some companies are investigating removing faulty mitochondria in the brain. Mitochondria are energy generating structures which may go awry over the course of many decades, contributing to the death of dopamine-producing cells. One particularly dramatic approach taken by the company BlueRock Therapeutics is even attempting to reverse the course of the disease by using stem cells to generate new dopamine-producing neurons which are then implanted in the brain, replacing the lost cells.
“There are many trials currently ongoing that are looking to unlock treatments to slow down the progression of Parkinson’s,” says Dr Wathes. “Getting a timely diagnosis is really important as it allows people to start interventions like medication and physical activity sooner.”
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