Parkinson’s disease – what does the future hold?

With the prevalence of Parkinson’s disease increasing, it is imperative that we improve resources and services to provide adequate treatment and care for those affected by this debilitating disease

Dr Stephen McWilliams, Consultant Psychiatrist, Saint John of God Hospital, Stillorgan

April 1, 2024

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  • World Parkinson’s Day1 takes place annually on April 11 to raise awareness of this movement disorder that is increasing in prevalence.2 The date coincides with the birthday in 1755 of James Parkinson, an English surgeon and apothecary who is noted for his 1817 publication, ‘An Essay on the Shaking Palsy’. In it, he described ‘paralysis agitans’, which the French neurologist Jean-Martin Charcot renamed Parkinson’s disease in 1872. 

    Parkinson’s disease, as we know, is a movement disorder associated with a degeneration of the dopaminergic neurons in the substantia nigra. It typically presents with a pill-rolling tremor, cogwheel rigidity, bradykinesia and postural instability up to and including a festinant gait.3 Associated difficulties can include problems chewing and swallowing, changes in speech, urinary issues of the autonomic nervous system, orthostatic hypotension, pain, sleep disturbance, psychiatric symptoms and other challenges. Age is a risk factor, with the average age of onset approximately 70 years, while the illness is more common in men and people with a positive family history of Parkinson’s disease. 

    Diagnosis typically involves a detailed history and neurological examination which may be supported by a dopamine transporter (DaT) scan which detects gamma rays emitted following injection of a mildly radioactive substance. Treatment may include: medications to increase the levels of dopamine in the brain (eg. levodopa); agonists to mimic dopamine (eg. apomorphine, pramipexole, ropinirole or rotigotine); medications to inhibit dopamine breakdown (eg. MAO-B inhibitors such as rasagiline or selegiline, and COMT inhibitors such as entacapone, opicapone or tolcapone); anticholinergics (eg. benztropine); and others (eg. amantadine). Surgical options such as pallidotomy and thalamotomy have been largely replaced by deep brain stimulation, where electrodes are surgically implanted in the subthalamic nucleus or globus pallidus to block the signals that cause the motor symptoms of Parkinson’s disease. And of course, physiotherapy, exercise and diet play an important role.

    According to the World Health Organization, the global prevalence of
    Parkinson’s disease has doubled in the past 25 years.2 In 2019, it was estimated that some 8.5 million individuals were living with the disease, while disability and death attributable to it are increasing faster than for any other neurological disorder. In 2019 alone, according to WHO estimates, Parkinson’s disease was responsible for 5.8 million disability-adjusted life years (an 81% increase since 2000) and some 329,000 deaths (a 100% increase since 2000). The WHO also cites a marked global inequality in the availability of resources and services to provide treatment and care for people with Parkinson’s disease, particularly those in low- and middle-income countries where there are approximately 0.03 neurologists per 100,000 population compared to 4.75 in high-income countries.

    In May 2022, the World Health Assembly endorsed the WHO’s Intersectoral Global Action Plan on Epilepsy and Other Neurological Disorders 2022-2031. The latter include Parkinson’s disease and the Global Action Plan aims to bridge the gaps that exist in services through a “comprehensive, coordinated response across sectors” through policy prioritisation and governance to ensure timely and effective prevention, diagnosis, treatment, care, research, innovation and health information. Further to this, on June 14, 2022, the WHO published a technical brief entitled ‘Parkinson’s Disease: A Public Health Approach’, which outlines the global burden of the disease along with treatment gaps and crucial areas for intervention that include: health policies for the implementation of appropriate strategies; education and awareness for prevention; access to treatment and care; and delivery of services. Let’s hope this approach makes a positive impact.

    © Medmedia Publications/Hospital Doctor of Ireland 2024