Parkinson’s disease (also known as Parkinson’s or PD) is a life-long degenerative disorder of the central nervous system that mainly affects the body’s motor system (its ability to control muscles and movement). It is known as a movement disorder because of the tremors and slowing and stiffening of movements that it can cause.
Symptoms gradually worsen over time. They usually emerge slowly and the most obvious early symptoms are tremor, rigidity, slowness of movement, and difficulty with walking. As the disease progresses non-motor symptoms such as cognitive changes, mood disorders (like depression and anxiety) and fatigue or apathy become more common. Symptoms and the rate of progression vary from person to person, and it is not possible to predict the path the disease will take.
Parkinson’s occurs when brain cells that make dopamine (a chemical produced in a small part of the brain called the substantia nigra) stop working or die. Dopamine is a neurotransmitter which means that it coordinates movement by enabling the brain cells involved in movement control to communicate. Dopamine is also primarily responsible for emotional responses and the ability to feel pleasure and pain. As these cells die the brain becomes deprived of dopamine and symptoms develop.
Over 6 million people worldwide have Parkinson’s. Scientists and researchers believe a combination of genetic factors, environmental factors, and ageing are the cause of Parkinson’s disease. Some researchers estimate that about 30% of Parkinson’s risk is explained by genetics but age is considered to be the most significant risk factor. Due to an ageing population, researchers project the number of people with Parkinson’s will double by 2040.
Other factors such as head injury or exposure to certain pesticides have also been associated with an increased chance of developing Parkinson’s disease. However, for most people, the specific cause of Parkinson’s will remain unknown.
There is no specific test for Parkinson’s, but there are three primary symptoms that help doctors make a diagnosis:
Bradykinesia is one of the classic symptoms of Parkinson’s disease – basically, it means slow movements – often a stooped posture and a slow, shuffling walk. Some patients may eventually lose their ability to start and keep moving, and after some years may not be able to move at all (this is known as akinesia or ‘freezing’).
The involuntary shaking of particular parts of the body is probably the most widely recognised symptom of Parkinson’s disease. The tremor may affect only one part or side of the body, especially in the early stages of the disease. Not everyone with Parkinson’s disease has tremor.
Stiff and inflexible limbs or joints affect most people with Parkinson’s and often begins in the legs and neck. The muscles become tense and contracted, and some people may feel pain or stiffness.
Bradykinesia plus either tremor or rigidity must be present for a Parkinson’s disease diagnosis to be considered. A neurologist will diagnose Parkinson’s based on medical history, a review of signs and symptoms, and a neurological and physical examination.
A person with Parkinson’s disease can also experience a wide range of other physical and psychological symptoms such as depression and anxiety, memory problems, postural instability (balance problems), small handwriting, loss of smell, trouble sleeping, constipation and dizziness or fainting.
Currently, there is no cure for Parkinson’s, so treatments are focused on reducing its symptoms. Understanding the nature of the disease, its likely progression, and the treatments available, is an important factor in managing the condition and its impact on your life. Treatment options vary from person to person and include medications and surgery.
While Parkinson’s itself is not fatal, it is progressive, and increasingly disabling, and the disease complications can be serious. It is possible to have a good quality of life with Parkinson’s;11 work with your doctor to explore the available options then follow the recommended therapies to reduce symptoms.
Although there is currently no cure for Parkinson’s disease, treatments are available to help reduce the main symptoms and maintain quality of life for as long as possible. Treatment for each person with Parkinson’s is based on their individual symptoms – there is no standard treatment. Treatments available include medication and surgical therapy, lifestyle modifications, and supportive treatments.
There are many medications available to treat the Parkinson’s symptoms, although none as yet that reverse the effects of the disease. It is common for people with Parkinson’s to take a variety of medications — often at different doses and at different times of day — to manage symptoms. These medications can be helpful in the early stages, but their effectiveness generally decreases over time.
The type of medication your doctor may prescribe will depend on your symptoms and needs.
Lifestyle changes may counter some symptoms of the disease and may help improve your daily life: things like getting more rest, ongoing aerobic exercise, physical therapy that focuses on balance and stretching, dietary changes and speech therapy.
Deep brain stimulation is an established treatment for people with movement disorders whose symptoms aren’t controlled with medication.
Deep brain stimulation (DBS) involves a surgical procedure to implant electrodes in certain areas of the brain. These implants send electrical impulses to the specific areas of the brain that control movement. The amount of stimulation is controlled by a pacemaker-like device placed under the skin in the upper chest. A wire travels under the skin to connect the device to the electrodes in the brain.
Deep brain stimulation won’t cure your disease, but it may help lessen your symptoms. If deep brain stimulation works, your symptoms will improve significantly, but they usually don’t go away completely. In some cases, medications may still be needed for certain conditions, and deep brain stimulation isn’t successful for everyone.
11 Schüpbach W, Rau J, Knudsen K, Volkmann J, Krack P, Timmermann L, et al. Neurostimulation for Parkinson’s disease with early motor complications. EARLYSTIM Study. N Eng J Med. 2013;368:610-622