Overview
Parkinson disease (PD) is a degenerative condition of the brain associated with motor symptoms (slow movement, tremor, rigidity, walking and imbalance) and a wide variety of non-motor complications (cognitive impairment, mental health disorders, sleep disorders and pain and other sensory disturbances). Motor impairments, such as dyskinesias (involuntary movements) and dystonias (painful involuntary muscle contractions) contribute to limitations in speech, mobility and restrictions in many life areas. Progression of these symptoms results in high rates of disability and care requirements. Many people with PD also develop dementia during the course of their disease.
While PD is the most common movement disorder, other movement disorders exist such as multiple system atrophy, progressive supranuclear palsy, chorea, ataxia and dystonia. Some movement disorders have similar symptoms to PD such as tremor, slow movement and rigidity. All movement disorders share the same challenges as PD regarding diagnostic and treatment gaps and access to medication, particularly in low- and middle-income countries (LMIC).
Risk factors for PD include increasing age, although younger people can be affected as well. Men are more affected than women. A number of studies have shown that environmental factors, including pesticides, air pollution and industrial solvents could increase the risk of PD.
The cause for PD is not known but is thought to arise from a complex interaction between genetic factors and exposure to environmental factors such as pesticides, solvents and air pollution throughout life.
Epidemiology
Globally, disability and death due to PD are increasing faster than for any other neurological disorder. The prevalence of PD has doubled in the past 25 years. Global estimates in 2019 showed over 8.5 million individuals with PD. Current estimates suggest that, in 2019, PD resulted in 5.8 million disability-adjusted life years, an increase of 81% since 2000, and caused 329 000 deaths, an increase of over 100% since 2000.
Assessment and care
PD is a clinical diagnosis that not only can be made by neurologists but also by trained non-specialist health-care workers. Assessment and management of PD by trained non-specialized health-care workers in primary care is particularly important in areas where specialist neurological services are unavailable, such as in some LMIC.
Although there is no cure, medicines, surgical treatment and other therapies can treat the symptoms of PD. Levodopa/carbidopa remains the most common and effective medication and is on the WHO Model List of Essential Medicines. Other medications, such as anticholinergics, or therapies such as deep brain stimulation can also treat symptoms of PD, especially tremors as well as to reduce medicine intake. However, many medications and surgical resources are not accessible, available or affordable everywhere.
As with many degenerative neurologic disorders, nonpharmacological management such as rehabilitation can offer relief. Specific types of physiotherapy including strength training, gait and balance training, and hydrotherapy can help improve functioning and quality of life for people with PD and other movement disorders. They can also reduce the strain on carers.
Telemedicine can also be used to increase the access to care for people with PD.
Impact on families and carers
Informal carers (i.e. most commonly family members and friends) spend many hours daily providing care for people living with PD. This can be overwhelming. Physical, emotional and financial pressures can cause great stress to families and carers, and support is required from the health, social, financial and legal systems. Useful support resources from other conditions can be drawn upon, such as WHO’s iSupport programme for dementia.
Human rights
People with PD are often subject to stigma and discrimination, including unjust discrimination within the workplace and lack of opportunities to engage and participate in their communities.
People with PD require accessible health services for general health-care needs like the rest of the population, including medicine access, promotive and preventive services and prompt diagnosis, treatment and care. A common barrier is created by health-care providers’ inadequate knowledge and understanding of PD and myths that PD is a contagious illness or a normal part of aging.
WHO response
In May 2022, the World Health Assembly endorsed the Intersectoral global action plan on epilepsy and other neurological disorders 2022–2031. The action plan will address the challenges and gaps in providing care and services for people with epilepsy and other neurological disorders such as PD that exist worldwide and ensure a comprehensive, coordinated response across sectors. This includes raising policy prioritization and strengthening governance, providing effective, timely and responsive diagnosis, treatment and care, implementing strategies for promotion and prevention, fostering research and innovation and strengthening information systems.
A WHO technical brief entitled Parkinson disease: a public health approach is available for policy-makers, health programme managers and planners, health-care providers, researchers, people with PD, carers and other stakeholders. It outlines the important action areas for intervention in PD including global health policies focused on prevention and risk reduction, education and awareness and access to treatment and care at various levels of the health system.
WHO’s iSupport, a knowledge and skills training programme for carers of people living with dementia is available as an online course and a hardcopy manual. iSupport Lite includes easy-to-read posters and a brief video that can act as a quick reference or a refresher, reinforcing previously acquired caregiving skills and knowledge.