Which are the symptoms?
The diagnosis of Parkinson's disease is based on the presence of 3 key symptoms: resting tremor, hypertone (or rigidity), and bradykinesia. Tremor at rest is a rhythmic tremor (typically of the hands) present when the muscles are relaxed, tending to decrease during voluntary movements, disappear during sleep and worsen in case of stress. Hypertone is an increase in stiffness at the muscle level making movement difficult. Bradykinesia, on the other hand, refers to a slowdown in voluntary movements, which also become less extensive and difficult to initiate. In addition to these, a variety of other accompanying symptoms may be present, including: difficulty maintaining balance (postural instability), alterations in posture (which becomes curved) and gait (tendency to drag one's feet, with small steps and reduced arm swings). In more advanced stages of the disease, patients tend to stop suddenly and describe the sensation of having their feet glued to the ground ("freezing" phenomenon). Others involuntarily accelerate their stride in an erratic manner to avoid falling (this tendency is called festination). Symptoms that are more nonspecific, but can begin several years earlier than motor symptoms, include: sleep alterations, including insomnia and so-called REM sleep behavior disorders, in which people dream vividly and tend to fidget and move around in bed during sleep; depression; decreased sensitivity to odors (hyposmia); constipation; and urinary issues. In advanced forms of the disease, some individuals may additionally develop cognitive deficits leading to dementia.
- resting tremor
- alterations in posture and gait
- sleep alterations
- urination disorders
- cognitive deficits
How is it diagnosed?
Evaluation by neurologist using a specialized objective examination is necessary for the diagnosis of Parkinson's disease. This includes assessment of tremor, rigidity, ability to perform rapid alternating movements, balance, and ambulation. If the clinical diagnosis is unclear, the doctor may give the person levodopa, the first and main drug used to treat Parkinson's disease. If levodopa induces marked improvement, the patient is likely to have Parkinson's disease. Neuroradiological examinations such as CT or MRI of the brain are performed to exclude the presence of other causes of Parkinsonism (especially vascular), but are not yet able to provide specific elements in the diagnosis of Parkinson's disease. A particular functional imaging method, called DaT SCAN, is able to confirm or exclude the suffering of dopamine-containing neurons in an early stage of the disease. Myocardial scintigraphy performed with the 123MIBG tracer can also be useful in the early stages of the disease as it helps to highlighy the alteration of noradrenergic transmission in the heart.
How is it treated?
To date, there are no drugs or procedures that can definitively cure Parkinson's disease. However, there are several very effective options to alleviate its symptoms and allow patients to carry out normal daily activitie. Levodopa is the main one of these options, since it is able to directly supplement the lack of dopamine that causes the symptoms of the disease, but there are also several other classes of molecules (e.g., dopaminoagonists, MAO-B inhibitors, COMT inhibitors) that are often used in combination with levodopa and with each other, especially if levodopa has lost efficacy (as can happen after several years or decades of disease) or is not tolerated due to the emergence of side effects. The pharmacological therapy must always be associated with motor rehabilitation performed by an experienced physiotherapist who defines a protocol based on the characteristics and symptoms of the patient. When pharmacological therapies are no longer sufficient to control symptoms or when important side effects appear, for some categories of patients without cognitive deficits and psychiatric disorders, deep brain stimulation, a neurosurgical intervention performed with light sedation that involves the insertion of brain electrodes vicariating the function of dopamine, may be indicated.