Parkinson’s disease is a chronic, progressive neurodegenerative disorder of the central nervous system and one of the most common movement disorders, particularly among older adults. The condition primarily affects movement, causing symptoms such as bradykinesia, resting tremor, and muscle rigidity. However, Parkinson’s disease does not affect movement alone. It may also cause disturbances in sleep, mood, autonomic nervous system function and, in some patients, cognitive function. Symptoms usually develop gradually and may initially be mild and more pronounced on one side of the body. Early diagnosis of Parkinson’s disease and individualized treatment can significantly contribute to controlling symptoms and maintaining mobility, independence, and quality of life.

Parkinson’s Disease and the Role of Dopamine

Parkinson’s disease is associated with the progressive loss of nerve cells in areas of the brain involved in controlling movement, particularly the dopaminergic neurons of the substantia nigra. The reduction in available dopamine affects the function of neural circuits that regulate movement and contributes to the development of the characteristic motor symptoms. The exact cause of Parkinson’s disease is not fully understood. It is believed that a combination of genetic, environmental, and biological factors contributes to its development.

Motor Symptoms of Parkinson’s Disease

The main motor symptoms include:

• bradykinesia, meaning slowness and difficulty performing movements
• resting tremor, which often begins in one hand
• muscle rigidity
• reduced arm swing on one side while walking
• smaller and slower steps
• difficulty initiating movement
• reduced facial expression
• reduced voice volume
• micrographia, meaning progressively smaller handwriting
• difficulty with fine hand movements

In more advanced stages, balance problems, postural instability, freezing of gait, and an increased risk of falls may develop. Not all patients experience the same symptoms, and tremor does not necessarily occur in every person with Parkinson’s disease.

Non-Motor Symptoms of Parkinson’s Disease

Parkinson’s disease can cause significant non-motor symptoms, some of which may appear even before the characteristic motor manifestations.

These may include:

• sleep disturbances
• reduced sense of smell
• constipation
• orthostatic hypotension
• urinary problems
• chronic fatigue
• anxiety
• depression
• apathy
• pain
• difficulties with attention and thinking
• cognitive decline in some patients

Recognizing and treating these symptoms is an important part of overall management, as they can significantly affect everyday functioning and quality of life.

Early Symptoms of Parkinson’s Disease

Parkinson’s disease usually begins gradually, which can make it difficult to determine the exact time of onset. Early changes may include slowing of movement, tremor in one hand, rigidity, changes in walking, reduced arm swing, smaller handwriting, or changes in facial expression and voice. Some non-motor symptoms, such as reduced sense of smell, constipation, and certain sleep disorders, may precede the motor symptoms by a considerable period of time. However, these symptoms are also common in other conditions and, on their own, do not confirm a diagnosis of Parkinson’s disease.

Diagnosis of Parkinson’s Disease

The diagnosis of Parkinson’s disease is primarily clinical and is made by a neurologist based on the patient’s medical history and a detailed neurological examination. Particular importance is placed on identifying parkinsonism, with bradykinesia as a key feature in combination with resting tremor and/or muscle rigidity.

During the neurological examination, the following may be assessed:

• speed and range of movement
• muscle tone
• presence and characteristics of tremor
• gait
• balance and posture
• fine movements of the upper limbs
• symmetry of symptoms
• speech and facial expression

The progression of symptoms and response to dopaminergic treatment can also provide important diagnostic information.

Tests for Parkinson’s Disease

There is no single blood test or imaging examination that can independently confirm Parkinson’s disease. In many cases, the diagnosis can be established from the patient’s medical history and characteristic clinical presentation. However, when atypical features are present or there is diagnostic uncertainty, additional investigations may be required to exclude other causes of parkinsonism.

Depending on the individual case, these may include:

Brain Magnetic Resonance Imaging (MRI): Mainly used to exclude other neurological conditions that can cause similar symptoms.

Dopaminergic system imaging (DaTscan): This may be used in selected cases when there is diagnostic uncertainty. It is not necessary for every patient and, on its own, cannot distinguish between all the different causes of parkinsonism.

Laboratory or other investigations may also be required depending on the patient’s age, symptoms, and clinical presentation.

Parkinson’s Disease and Parkinsonism

Not all symptoms of parkinsonism are caused by Parkinson’s disease. Similar motor symptoms may occur in other neurodegenerative disorders, vascular brain disease, as a result of certain medications, or in other neurological conditions. For this reason, an accurate differential diagnosis is important, particularly when the clinical presentation progresses in an atypical manner or the response to treatment is not as expected.

Treatment of Parkinson’s Disease

Although there is currently no treatment that can completely eliminate the disease, effective therapeutic options are available that can significantly control symptoms for long periods of time.

The treatment of Parkinson’s disease is individualized according to:

• the patient’s age
• the duration and stage of the disease
• the severity of motor symptoms
• the impact of symptoms on everyday life
• the presence of non-motor symptoms
• coexisting medical conditions
• response and tolerance to treatment

The goal is to maintain mobility, functional ability, and quality of life as effectively as possible.

Pharmacological Treatment of Parkinson’s Disease

Levodopa is one of the most effective treatments for the motor symptoms of Parkinson’s disease and is usually administered in combination with a peripheral decarboxylase inhibitor.

Depending on the individual case, other classes of medication may also be used, including:

• dopamine agonists
• MAO-B inhibitors
• COMT inhibitors
• amantadine
• other treatments depending on the patient’s specific symptoms

The choice and combination of medications should be individualized and reassessed as the disease progresses.

Motor Fluctuations and Dyskinesias

After years of treatment, some patients may develop motor fluctuations, in which the effectiveness of medication varies throughout the day. Patients may experience “OFF” periods, during which symptoms return or worsen before the next dose, as well as involuntary movements known as dyskinesias. In these situations, adjustments to the dosage, timing, or combination of medications may be necessary.

Advanced Treatments for Parkinson’s Disease

In selected patients with advanced Parkinson’s disease and motor fluctuations that are not adequately controlled with conventional medication, more specialized treatment options may be considered.

These may include:

• Deep Brain Stimulation (DBS)
• continuous dopaminergic therapies delivered through appropriate pump systems

Selecting patients for these treatments requires specialized neurological assessment and depends on several factors, including the type of symptoms, response to levodopa, cognitive status, and overall health.

Exercise and Rehabilitation in Parkinson’s Disease

Regular physical activity is an important part of the overall management of Parkinson’s disease.

An individualized exercise program may include:

• aerobic exercise
• strengthening exercises
• balance training
• gait training
• flexibility and mobility exercises

Depending on the patient’s difficulties, physiotherapy, occupational therapy, and speech and language therapy may also be beneficial, particularly when there are problems with walking, daily activities, speech, or swallowing.

Follow-Up of Parkinson’s Disease

Parkinson’s disease is a chronic and progressive condition and therefore requires regular neurological follow-up. During reassessment, evaluation is not limited to tremor and mobility. Gait, falls, sleep, mood, blood pressure, bowel and bladder function, swallowing, cognitive function, and the patient’s overall level of independence may also be assessed. As the disease progresses, treatment may need to be adjusted to address both motor and non-motor symptoms. Early diagnosis and individualized treatment of Parkinson’s disease, combined with regular follow-up, exercise, and appropriate rehabilitation, can contribute significantly to better symptom control and help preserve the patient’s functional ability, independence, and quality of life.