PD has been described as a progressive neurological disorder caused by the diminished presence or absence of the neurotransmitter dopamine. For victims of PD, in a region of the brain called the substantia nigra, cells degenerate and lose normal functionality. The reasons as to why these cells become degenerative is unknown at this time. In future blogs, we will discuss the definition, history, and possible causes of PD.
This disease is often associated with the aging population. One percent of people older than 65 exhibit PD. Parkinsonism can be found in about 15 percent of people between the ages of 65 and 74. There is a small chance of developing PD if one has progressed to the age of 70 without exhibiting any signs of PD. Strangely enough, more than 50 percent of people older than 85 display some kind of parkinsonism. Read more here.
It is believed that 70 percent of all patients with Parkinson's have been correctly diagnosed, and that the incidence of Parkinson's is expected to grow 2 percent per year in the United States, Japan, and in Europe.
There are some tell tale signs associated with PD, which, in union, could signal PD.
These signs include:
- Isolated tremors in an arm or a leg
- Change in handwriting
- Difficulty walking or balancing
- General slowness in daily activities
A physician will diagnose PD based on the following four criteria:
Tremors - In what is described as a resting tremor, a non-moving limb (arm or leg) exhibits tremors that may subside with volitional movements (like reaching to grab an object).
Rigidity - Patients of PD often experience rigidity in their muscles (commonly termed cogwheel rigidity). This rigidity can sometimes cause stiffness and discomfiture.
Akinesia & Bradykinesia - Akinesia (lack of voluntary movement) and Bradykinesia (slowness of voluntary movement) are the distinguishing characteristics of PD. These affect all normal daily activities from rising out of chairs, bathing, eating, etc.
Postural Imbalance - Postural imbalance or a tendency to fall down can be symptoms of PD.
Because PD is so difficult to diagnose with certainty, D.B. Calne DB, B.J. Snow, C. Lee of the Neurodegenerative Disorders Centre, University Hospital, Vancouver, BC, Canada, have proposed a three-tiered system quantifying the confidence of a diagnosis:
- clinically possible
- clinically probable
- clinically definite
In order to diagnose PD as correctly as possible, it is important to quantify and itemize a patient's medical history and augment that with the patient's own understanding of his or her body and any changes that have occurred over time. One thing that is true is that the validity of the diagnosis increases as the disease advances.
