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Wednesday, August 27, 2014

Tests that could spot Parkinson's decades before symptoms start


Secretary Sharon Blight was diagnosed with Parkinson's disease at just 49
Secretary Sharon Blight was diagnosed with Parkinson's disease at just 49
Secretary Sharon Blight initially put the numbness and 
tingling in her right hand and foot down to a tennis injury. 
'I'd fractured my right collarbone after falling over on court 18 months before,' she recalls.
Surgery and physiotherapy restored full movement to her arm and shoulder, and when she developed the numbness and tingling, she thought it was a trapped nerve. But then her physiotherapist noticed a slight tremor in her foot and recommended seeing a GP.
'My GP said it was probably nothing to worry about, but I should see a neurologist,' says Sharon, a married mother-of-two from Aldershot, Hampshire. 
But after ten minutes of examining her, the neurologist said he was almost certain Sharon had Parkinson's disease.
'I was in complete shock,' she says. 'I was only 49 and as far as I was concerned, Parkinson's was something that only affected the elderly and mainly men.' 
It's a common misperception, which will only have been cemented by recent announcements about celebrity patients. 
Comedian Billy Connolly, 71, has recently been diagnosed with the disease. Sir Roger Bannister, 83, the first man to run a four-minute mile and a former neurologist, has been suffering from Parkinson's for the past three years. 
Most sufferers are diagnosed later in life, on average at 65. But scientists now believe the disease, which affects 127,000 people in the UK, begins to develop up to 20 years before the appearance of the first symptoms, such as uncontrollable tremor, slow movements or muscle stiffness. This means many people may have hidden Parkinson's in their 40s or earlier. 
'There's a lot of debate about this but it's thought patients may start to lose nerve cells in the brain anywhere between five and 20 years before symptoms appear,' says Claire Bale, research communications manager with the charity Parkinson's UK.
Now the race is on to develop new ways to identify patients during the 'pre-onset' years, and give them a better quality of life.

    Parkinson's is caused by a loss of nerve cells in an area of the brain that controls movement and feelings of reward and addiction. These cells produce dopamine, a chemical that shuttles messages between the brain and nervous system, helping to control body movement.
    If these cells become damaged or die, levels of dopamine are reduced. Symptoms of the disease appear only when 80 per cent of the nerve cells have been lost.
    Parkinson's is diagnosed by studying a patient's symptoms and movement, often followed by a DAT scan, which measures dopamine levels in the brain.
    Scientists are trying to find ways to test for the condition in early stages. A most promising way is a blood test for raised levels of alpha-synuclein, which is released in clusters in the brain when the disease is setting in
    Scientists are trying to find ways to test for the condition in early stages. A most promising way is a blood test for raised levels of alpha-synuclein, which is released in clusters in the brain when the disease is setting in
    Professor Patricia Limousin, a specialist at the National Hospital for Neurology and Neurosurgery in London, warns that the classic symptoms neurologists instantly look for often go unnoticed by GPs.
    'We look for tremor, especially when the arm is at rest, and slowness of movement, reduced swinging of the arm when walking, and stiffness of muscles. 
    'Most patients have had some or all of these symptoms for months or years before they see us. 
    Some may have noticed a slight tremor but didn't seek help, others have been to a GP but are told it's down to stress.'
    The disease has been known about since ancient times - it was referred to as 'shaking palsy' as early as AD175. 
    But what triggers it is still unclear. The consensus seems to be that some people may carry a mixture of genes that predispose them to damage by toxins in the environment - such as from pesticides - and this sets Parkinson's in motion.
    Men are 50 per cent more likely to get it than women. One theory is that oestrogen may have a protective effect.
    ''I was in complete shock. I was only 49 and as far as I was concerned, Parkinson's was something that only affected the elderly and mainly men'
    For most people, having Parkinson's will not significantly affect life expectancy. But in its advanced stages it can lead to chronic pain, sleep disruption, anxiety and depression, and problems affecting movement. Years of being ill can leave patients vulnerable to infections. 
    The earlier Parkinson's is treated, the better, as currently drugs can slow down - but not halt - the loss of brain cells.
    So scientists are trying to find easy ways to test for the condition in the early stages. One of the most promising is a blood test for raised levels of the protein  alpha-synuclein. This is released in clusters in the brain when the disease is setting in - but usually before symptoms appear. 
    In 2011, scientists at Lancaster University discovered a way to detect the protein in blood samples of Parkinson's patients. Now trials are looking at whether an alpha-synuclein blood test could be the early warning sign doctors hope for
    An Austrian team is even testing a vaccine that could prime the immune system to attack and destroy the clusters. First results are due in a few months.
    'Although we know alpha-synuclein is involved in  nerve-cell death in the brain, there are many types of the same protein, and we are still some way off having a readily available blood test,' says Claire Bale.
    There are other, perhaps slightly surprising, clues that Parkinson's may be developing.
    One is a loss of smell. As brain cells die off, one of the areas of the brain affected fairly early is the olfactory bulb, which processes and identifies odours. Up to 80 per cent of patients recall losing some or all of their sense of smell months or years before the onset of other symptoms.
    Another potential early warning sign is constipation. As dopamine-producing cells die off, muscles controlling contractions in the bowel also seize up, because dopamine is produced by nerve cells in the enteric nervous system - which controls digestion. Around 60 per cent of sufferers experience constipation early on.
    'We think these nerve cells outside of the brain are affected earlier, or start to show symptoms earlier than those in the brain,' says Claire Bale.
    Scottish actor Billy Connolly is a sufferer
    Scottish actor Billy Connolly is a sufferer
    A third indicator is vivid dreams, or acting out nightmares. At  least five years before patients suffer stiffness, many have  REM sleep behaviour disorder.
    Rapid eye movement sleep is the stage where we have vivid dreams. To stop us acting them out, the brain temporarily paralyses us. But the damage to brain cells in Parkinson's switches off this mechanism.
    Individually, none of these indicators are strong enough to confirm that Parkinson's has set in. But it may be that a collection of such warning signs could justify further investigation.
    It's hoped new drugs could stop the progression of the disease altogether. Current treatments, such as levodopa - a drug which has been around for nearly 50 years - address only the  symptoms by replacing some of the missing dopamine. 
    A more extreme treatment is deep-brain stimulation, where electrodes are implanted into the brain to 'deactivate' affected areas.
    It can ease symptoms, and patients are often able to reduce their drug dosage. This is vital: dopamine-replacing drugs have been associated with severe behavioural side-effects, such as gambling or sex addiction. 
    One of the most promising new treatments could be a relatively cheap drug already widely and used for type 2 diabetes.
    At £18 per injection, exenatide helps lower blood sugar levels. But a study with 20 patients last year at University College  London found it appeared to  slow down, or in some cases halt, the progression of Parkinson's. Bigger trials are planned.
    Meanwhile, Sharon, now 54, takes a daily cocktail of drugs, including levodopa and up to five paracetamol.
    'I hate bedtime because I know in the morning I will be so stiff I can't get up,' says Sharon, who fundraises in her spare time for Parkinson's research.
    'I've had to give up my beloved tennis and now play bowls. I'm determined to not let my illness beat me. I may have Parkinson's disease, but it doesn't have me.'


    Read more: http://www.dailymail.co.uk/health/article-2734154/Tests-spot-Parkinsons-decades-symptoms-start.html#ixzz3BbkieQSP 
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