Parkinson’s: causes, symptoms, treatment and prevention
Parkinson’s is the most common neurodegenerative disease after Alzheimer’s. It is estimated that approximately 1% of people over the age of 60 suffer from this disorder.
Although Parkinson’s disease is believed to have genetic causes and is therefore unlikely to be prevented or cured, there are treatments capable of alleviating its symptoms and delaying the physical and cognitive decline that it brings, especially medications such as levodopa.
What is Parkinson’s disease?
Parkinson’s disease affects the regions of the brain that produce dopamine, a neurotransmitter that enables voluntary and precise (fine) movements in addition to other non-motor functions.
The main symptoms of this disease, described by James Parkinson in 1817, include resting tremors , muscle stiffness and impaired speech and gait.
Parkinson’s disease usually begins between the ages of 50 and 60 , although it is not uncommon for it to begin in the 1930s. The course of this disease is chronic and usually causes severe disability in the person who suffers it after about 10 years.
While some treatments can alleviate symptoms, once Parkinson’s disease develops there is no cure.
Causes of this pathology
The symptoms of Parkinson’s are the result of the degeneration of subcortical brain structures . The destruction of dopaminergic neurons in the basal ganglia, especially in the region known as the “substantia nigra”, hinders multiple cognitive and motor functions.
The causes of Parkinson’s disease are unknown . A genetic component is known to exist, as 15% of those diagnosed have close relatives who also have or have had the disorder.
The development of Parkinson’s is likely due to the combination of mutations in several genes . Exposure to some toxins, such as those in pesticides, herbicides and heavy metals, is also considered a risk factor, although the importance of these environmental factors appears to be less than that of genetics.
The first symptoms of Parkinson’s disease usually include slight tremors that progressively intensify . The same is true of the other symptoms, which are also related to movement.
Other early signs include stiffness of the arms when walking, difficulty articulating sounds, and lack of facial expression (the characteristic “mask face” of this disease).
Subsequently, all these symptoms will worsen as the degree of brain involvement increases, evolving in many cases to a diagnosis of dementia caused by Parkinson’s disease.
1. Resting tremors
Resting tremors are slow and wide and occur in a part of the body that is not making any movement . They are very characteristic of Parkinson’s disease, to the extent that in many cases they are called “parkinsonian tremors”.
Usually they start in one of the hands, but as the disease progresses they spread to both arms and can affect the legs and head as well.
Resting tremors generally occur along with muscle stiffness and slowed motor function, and occur to a lesser extent during voluntary movements.
2. Muscle stiffness
The increased muscle tone that results from Parkinson’s disease leads in turn to stiffness in the muscles, which limits movement and causes pain .
A characteristic of Parkinson’s is what we call “sprocket stiffness,” which means that when another person moves the patient’s affected limbs, they come to a halt, showing excessive resistance, as if something were holding up the joints. However, the problem is not in the joints, but in the patterns of muscle activation that the nervous system orders in real time.
3. Bradykinesia (motor slowness)
Parkinson’s disease makes movement progressively more difficult, especially in the extremities. This decreases the ability to perform simple manual tasks , which are performed more and more slowly. It also makes it more difficult to sit up and walk.
On the other hand, the difficulties caused by these motor difficulties also make there is little willingness to move, so the motor symptoms are compounded by a psychological effect that overlaps with the above.
4. Loss of automatic movements
Involvement of the basal ganglia causes a progressive loss of automatic movements in people with Parkinson’s. This is manifested in the absence of blinking, smiling and swinging arms when walking .
5. Posture and balance problems
In Parkinson’s disease the postural reflexes are affected, giving rise to a bent and flexed posture which in turn causes lack of balance or postural instability, facilitating falls and making it more difficult to move around. In addition, in the case of falls, avoiding falling to the ground with all your weight and then getting up also costs more.
6. Affect on walking
One of the most visible consequences of the motor problems we have mentioned is gear changes. People with Parkinson’s usually take shorter steps, shuffle their feet and move their arms less when walking.
Difficulties occur in all phases of walking, so that not only does walking become more difficult, but also the ability to start walking, to turn and to stop decreases.
7. Speech difficulties
Some of the most common speech problems in Parkinson’s cases are decreased volume and pronunciation difficulties , resulting from motor impairments in the articulatory organs.
Prosody is altered, speech may be accelerated (tachyphaemia), and some words and phrases may be repeated compulsively (palilalia). These symptoms appear to be more common in cases where Parkinson’s disease is cured by dementia.
As a result, the person’s social life is damaged, and sometimes predisposes them to seek isolation.
The changes in the brain caused by Parkinson’s can lead to the development of a form of dementia specific to this disease .
Dementia is diagnosed in 20-60% of Parkinson’s cases, although a lower degree of cognitive impairment may also occur in the rest. Dementia caused by Parkinson’s disease is especially likely if the patient is a male, is older, has a late onset of the disorder, or does not respond well to medication.
Compared to Alzheimer’s disease, the most common cause of severe cognitive impairment, in Parkinson’s dementia motor impairments are more relevant at the onset. This is due to the dopamine deficit characteristic of Parkinson’s. In contrast, the cognitive symptoms are more intense in the early stages of Alzheimer’s.
However, as Parkinson’s disease progresses, cognitive symptoms such as memory loss and delusions increase. The different types of dementia differ less when they are in an advanced stage.
Prevention and treatment
It is not clear whether the occurrence of this disease can be prevented. Some studies suggest that caffeine and green tea consumption reduce the risk of Parkinson’s.
Furthermore, the practice of moderate intensity aerobic exercise in adulthood has been associated with a lower probability of developing this disease in old age. However, the preventive effectiveness of sport has not yet been confirmed, and the same is true of caffeine and green tea.
Once Parkinson’s disease has developed, its symptoms can be alleviated using different types of treatment. The management of this disorder is mainly done with medication that increases the levels of dopamine in the body.
Levodopa is the most widely used drug to treat Parkinson’s, especially in its early stages . This compound increases the concentration of dopamine. As the disease progresses, levodopa may lose effectiveness, in which case it is replaced by dopamine agonists such as pramipexole and ropinirole.
Other forms of treatment, such as surgery, are less effective than levodopa and similar drugs. Physical exercise and relaxation techniques also help maintain mobility to a greater extent, slowing the progression of Parkinson’s disease.