Many think of a tremor as the quintessential warning sign of Parkinson’s disease, a degenerative neurological condition that affects more than 166,000 people in the UK.
But experts say other, more subtle symptoms may begin years before patients develop any changes in their movement.
In fact, a resting tremor – a rhythmic shaking of a body part when it’s at rest – isn’t actually needed to diagnose the condition.
And a surprising one in five Parkinson’s patients won’t develop one at all.
Instead, experts say new research into the condition – which is on the rise in the UK – has revealed it can have surprising warning signs that appear far earlier that previously thought.
One of the most common neurological disorders in the world, Parkinson’s is caused by a loss of nerve cells in an area of the brain responsible for producing dopamine, which helps coordinate body movement.
This lack of dopamine can lead to issues like tremors, falls and mobility issues and worsens over time as more cells die, with sufferers eventually left struggling to complete day-to-day tasks.
The condition has no cure, but symptoms can be treated with a combination of medication and physical therapy.
Experts say new research into Parkinson’s has revealed it can have surprising warning signs that appear far earlier that previously thought
The earlier the condition is diagnosed, the better access to treatments that significantly improve a sufferer’s quality of life, say experts.
But whilst neurologists often look for characteristic movement symptoms – like slowness, stiffness and resting tremor – when making a Parkinson’s diagnosis, other non-motor symptoms can often precede them by more than a decade.
These signs – which can include vision changes and constipation – begin during the early, or prodromal, phase of the disease, and mark the beginning of its slow onset.
By the time more recognisable motor symptoms begin, say doctors, up to 70 per cent of nerve cells in the part of the brain stem responsible for voluntary movement have already died.
Whilst not everyone who has these early symptoms will go on to develop Parkinson’s, doctors were keen to stress.
But research demonstrates that in some people, they can be the earliest signs of the devastating disease.
So, what should we be looking out for?
Loss of sense of smell
Up to 95 per cent of Parkinson’s sufferers will experience a loss or reduction in their sense of smell—known as anosmia—before they are diagnosed with the condition, say experts
Symptoms can include uncontrollable tremors, slow movements and muscle stiffness, but experts say they often only appear when about 80 per cent of the nerve cells have been lost
Up to 95 per cent of Parkinson’s sufferers will experience a loss or reduction in their sense of smell—known as anosmia—before they are diagnosed with the condition, say experts.
Research shows the symptom can show up around 20 years before the disease is diagnosed.
And people who lose their sense of smell have a fivefold increased risk of developing Parkinson’s in the future.
Some may not be aware that they are losing their smell as it can happen gradually, says Dr Ronald Postuma, professor of Neurology and Neurosurgery at McGill University in Canada.
And loss of smell can affect people in different ways – with some losing or gaining weight as they can no longer smell food, while others may find their mood impacted.
For some, it can be subtle and only dampen their smell, while others may struggle to smell at all.
It can also lead to safety concerns, with sufferers struggling to smell burning, for example.
Research suggests that the symptoms is caused by part of the brain responsible for processing smells—known as the olfactory bulb— being smaller in some people who have the disease.
Studies have also found that in Parkinson’s patients, there is a build-up of alpha-synuclein — a protein found in dopamine-producing cells—in this part of the brain.
In Parkinson’s patients, the proteins become tangled and form clumps, which experts believe may spread the disease throughout the brain.
Acting out dreams
Talking, thrashing or sitting up in your sleep could also be an early sign of Parkinson’s, say experts
Talking, thrashing or sitting up in your sleep could also be an early sign of Parkinson’s, say experts.
Normally during sleep, the body enters a state of near-total paralysis, known as rapid eye movement, or REM, sleep.
This is the sleep stage with the most vivid dreams.
But in those with REM sleep behaviour disorder, this paralysis is lost – leading people to physically act out their dreams.
This could be sitting straight up in bed, having one-sided conversations or even kicking or punching their partner.
And it won’t just leave you (and your partner) badly rested.
Studies show that between 50 and 70 per cent of people with REM sleep behaviour disorder will go on to develop Parkinson’s Disease or a related condition, like Lewys body dementia, within five to 10 years on average.
Those aged 50 and over with REM sleep behaviour have a shocking 130 times greater likelihood of developing Parkinson’s as those without the sleep condition.
Constipation
Most people will experience constipation at some point in their life – and usually, it’s not anything serious.
But constipation that persists for multiple weeks or more affects two-thirds of people with Parkinson’s.
Experts believe this is likely due to the fact that Parkinson’s can affect the nerves lining the digestive tract.
Studies have also found clumps of abnormal protein in the nerve cells lining the intestines of Parkinson’s patients.
And slowness of movement and rigidity —tell-tale signs of the condition—can affect the muscles in the bowel wall, meaning that waste products are not moved along in the bowel.
A large analysis of nine different studies found that people with constipation were twice as likely to develop Parkinson’s than those without constipation.
Another study, which followed 6,790 men aged 51 to 75 over a 24-year period, found that those who had a bowel movement less often than once a day had a greater risk of Parkinson’s.
‘Even people who are constipated in their 20s or 30s seem to have an increased chance of getting Parkinson’s 30, 40 years later,’ Professor Postuma told the Washington Post.
‘So, now we’re starting to wonder: Is the disease affecting the nerves that control the gut, or is being constipated a risk factor for Parkinson’s, as well?
Dizziness when standing up
Dizzy spells could be an early sign of dementia or Parkinson’s, researchers have warned.
Although some medicines or dehydration can cause light headedness, a recurrent problem may be an indicator of an illness called orthostatic hypotension.
‘When it’s neurological in origin — in other words, not dehydration, medication or a heart problem — about half of these patients develop Parkinson’s or a related condition,’ Professor Postuma told the Post.
‘So it’s a very high risk factor. Most people, though, don’t have a neurologic cause.’
Orthostatic hypotension is not as well evidenced as other early markers of Parkinson’s disease.
But studies have found that otherwise unexplained orthostatic hypotension was associated with an eventual diagnosis of Parkinson’s or a related condition in as many as 23 per cent of patients after a 10-year follow-up.