Approximately 7-10 million people worldwide, including about 10,000 Danes, live with Parkinson's disease (PD). PD is the fastest-growing brain disorder globally, but the cause of this increase remains unknown. In the Western world, the risk of developing PD is about 2,7%, that is 1 person out of 37 will develop PD*.
While most patients are diagnosed in their 60s, around 10% of patients receive a diagnosis before the age of 40.
PD is commonly associated with classical motor symptoms, including tremors and slow movements. However, patients may also develop a wide range of so-called non-motor symptoms, such as pain, sleep disorders, constipation, anxiety, depression, and dementia.
The causes of Parkinson's disease are not fully understood, and there is still no cure. However, there are various treatment options that can ease both the motor and many of the non-motor symptoms.
*The Incidence and Prevalence of Parkinson’s in the UK. Results from the Clinical Practice Research Datalink Reference Report (published Dec 2017) – Parkinson’s UK
Parkinson's disease is the most common neurodegenerative movement disorder. The disease affects, among other things, the dopamine-producing nerve cells in the brainstem. This results in a deficiency of the neurotransmitter dopamine in vital areas of the brain, including the so-called basal ganglia circuit, which is important for initiating and coordinating movements. As a result, patients develop motor symptoms such as
However, Parkinson's disease is not only a dopamine disorder. Many other important clusters of nerve cells are affected in both the central and peripheral nervous systems. This widespread impact of the disease often leads to the development of many other symptoms, collectively referred to as non-motor symptoms. These can include
The cause of Parkinson's disease is not fully understood but involves a complex interplay of genetic and environmental factors. The so-called Lewy pathology probably plays a very important role. It refers to a disease process where a common protein, alpha-synuclein, adopts an incorrect 3-dimensional shape (called misfolding). These misfolded proteins can aggregate into larger and larger accumulations, disrupting the normal function of nerve cells and eventually leading to cell death.
The misfolding process can spread from cell to cell through the nervous system and eventually affect large parts of both the brain and the peripheral nervous system. In the Danish Parkinson Research Centre, we hypothesise that misfolded proteins may originate in various locations. In some patients, they arise in the nasal mucosa and gain access to the brain via the olfactory nerve. In others, they arise in the enteric nervous system and travel into the brain via nerve connections between the gut, spinal cord, and brain.
We classify the two types as brain-first and body-first Parkinson's disease. Since the disease often appears to originate in either the nasal or intestinal mucosa, external factors such as infections, toxins, and other influences may trigger PD. Registry studies show that certain pesticides, environmental toxins, and infections can increase the risk of developing Parkinson's disease, but the disease can also occur without external influences.
It is important to emphasise that the brain-first and body-first model is still a scientific hypothesis, not yet fully proven. While Lewy pathology is likely to play a significant role, there are probably many other involved mechanisms. Studies indicate that patients with PD experience disruptions in various cellular functions, including energy metabolism, the immune system, and calcium and protein metabolism. Moreover, a wide range of genetic variations and mutations are known to undoubtedly contribute to the disease mechanisms.
As the disease progresses and Lewy pathology spreads, various nerve cell types will be disrupted and many cell types will be lost. This results in circulation disturbances and a loss of various important neurotransmitters in the brain. Lack of dopamine plays a central role in the development of movement disorders but also in other brain functions. Deficiency in other neurotransmitters like acetylcholine, noradrenaline, and serotonin can cause other symptoms such as anxiety, depression, fatigue, sleep disturbances, and pain.
We lack detailed knowledge of how the deficiency of these neurotransmitters and brain circuit damage are linked to symptoms experienced by the patients. Researchers continuously seek deeper insights into Parkinson’s most fundamental disease mechanisms. This understanding is crucial for developing new and better treatments and ultimately a cure.
Please note that the Danish Parkinson Research Centre is a research centre. We do not conduct clinical examinations or provide advice on clinical treatment. If you have questions regarding the diagnosis or treatment of your Parkinson's disease, please contact your own general practitioner or the attending hospital neurologist.
The diagnosis of Parkinson's disease is made by neurology specialists primarily based on clinical motor symptoms such as tremors, slowness, muscle stiffness, reduced facial expression, and reduced arm swing during walking. Other symptoms like constipation, reduced sense of smell, pain, sleep disturbances, depression, etc. can further raise suspicion of Parkinson's disease.
Various scans and laboratory tests can be conducted to support the clinical diagnosis, including blood tests, CT, or MRI scans. Some patients may undergo a PET or SPECT scan to measure whether the dopamine system in the brain is intact.
Ongoing research aims to develop new methods to improve the accuracy of diagnosing Parkinson's disease, potentially diagnosing it years before symptoms are experienced. Improved and more accessible scanning techniques are being developed, and researchers are making huge progress in developing tests that can confirm a Parkinson's diagnosis through cerebrospinal fluid, blood samples, and tissue samples from the skin, intestines, and other organs.
Please note that the Danish Parkinson Research Centre is a research centre. We do not conduct clinical examinations or provide advice on clinical treatment. If you have questions regarding the diagnosis or treatment of your Parkinson's disease, please contact your own general practitioner or the attending hospital neurologist.
Currently, there is no cure for Parkinson's disease. However, there are various treatments available to ease some of the symptoms experienced by patients.
Movement disorders can be reduced with various medications primarily targeting the dopamine system. In later stages of the disease, they may be eased using advanced treatments such as continuous dopamine replacement therapy via pump administration in the intestinal system.
Surgical treatment with deep brain stimulation is used for some patients who are in a late stage of the disease. It involves implanted electrodes that stimulate and thereby normalize movement circuits in the brain, almost like a pacemaker.
Some patients may experience other symptoms that can also be treated medically, such as constipation, sleep disturbances, pain, and depression. The treatment of Parkinson's disease is specialized and provided by neurology specialists.