Parkinson's disease is one of the most common neurodegenerative diseases in the elderly, accounting for approximately 1% prevalence among older adults aged 60 years and over. Parkinson's disease is considered significant to Thai public health. It affects the quality of life of patients with disabilities and increases the mortality rate. It also affects the quality of life of Parkinson's disease caregivers.
The main symptoms related to motor symptoms include:
- slow movement
- tremors at rest
- difficulty balancing
These lead to falls, collectively known as Parkinsonism. Parkinson's patients also have non-motor symptoms, or early warning signs of Parkinson's disease called Prodromal symptoms including:
- sleepwalking in the middle of the night
- inability to smell or taste food
- chronic constipation
First of all, let me emphasize that not every sleepwalker will have Parkinson's disease. This is because the symptoms mentioned above are not specific only to Parkinson's disease.
However, if people have these symptoms along with a family history of Parkinson's disease, the chances of developing Parkinson's disease increase. These warning signs medically indicate that neurodegenerative conditions have begun in the lower brainstem, a region that controls sleep, and the autonomic nervous system that controls excretion, for example. Research evidence suggests that these symptoms may precede the symptoms of motorized Parkinson's for up to 6-20 years.
Causes of Parkinson’s Disease
At present, we cannot diagnose people with Parkinson's disease based on these warning symptoms. One of the main reasons is due to the lack of specificity of these symptoms with Parkinson's disease which means nighttime sleepwalking can be caused by diseases other than Parkinson's disease. Anyhow, the information these warning signs conveys to us are that CNS degeneration has occurred in Parkinson's disease long before the patient's onset of movement symptoms. As one patient said about cramps or the problem of wearing shoes which seems to be a minor symptom, but in fact, dopamine levels had started to decline long before the symptoms appeared.
Where does Parkinson's disease actually begin? No one really knows yet. But the current study's data suggest neurodegeneration in Parkinson's disease may begin with the peripheral autonomic nervous system that controls bowel movements. This can explain constipation as one of the warning symptoms. Then, the degeneration will gradually ascend to the lower brain stem area which can explain sleepwalking symptoms. Until the degeneration reaches the upper brainstem, the patient experiences tremors and slow movements. This kind of information is important in making treatment decisions for the patient. The first thing is that long-declining dopamine levels should be replaced as soon as possible. Mild expressed symptoms do not indicate that they are just starting to occur. The human brain has the ability to substitute or compensate for the symptoms in question if necessary.
Therefore, the former belief was to start treating Parkinson's disease with medication only when a patient has severe symptoms and is unable to perform normal daily life which is not quite right according to today’s evidence. It is now confirmed by medical information that "Parkinson's disease requires early treatment." Another important piece of information that helps support early treatment is that current treatments clearly slow down the severity of the disease, resulting in patients treated early having a better quality of life, fewer complications, and a longer lifespan. For another reason, dopamine substitution, in theory, would save patients' brains from overwork during the substitution or compensate for missing symptoms.
Current diagnosis of Parkinson's disease
Let's go back to the current diagnostic criteria for Parkinson's disease. This is the clinical criterion currently accepted by physicians for the diagnosis of Parkinson's disease. Let's emphasize that this is a clinical criterion. Doctors can diagnose Parkinson's disease by taking a history and physical examination. Therefore, if this criterion is used by a medical professional in Parkinson's disease, it is about 95% accurate (no criterion is 100% accurate). Additional medical imaging examinations such as MRI or blood tests are not necessary. To diagnose Parkinson's disease according to this criterion, the patient must have primary symptoms of Parkinson's disease, called Parkinsonism, which is significant for the patient to have a slow movement or Bradykinesia. Without such symptoms, Parkinson's disease is not considered. Anyhow, in early Parkinson's patients, the slow symptoms may not be noticeable by activity. It generally requires a physical examination by a medical professional.
On the contrary, tremor at rest, the most noticeable symptom in Parkinson's disease, is seen in approximately 70% of Parkinson's, meaning that tremors are not necessarily present in the patient. All Parkinson's patients, especially young Parkinson's patients, usually experience slow movement, stiffening on one side of the body without tremors, and the other main symptoms including rigidity and postural instability. These main symptoms are collectively known as Parkinsonism. There are various possible causes of Parkinsonism. The most common is Parkinson's disease (about 70%) and other causes such as Parkinsonism-plus syndromes.
Prof.Dr. Roongroj Bhidayasiri
Specialist in neurology specific to Parkinson's disease and movement disorders