Parkinson’s Disease Research

Parkinson’s Disease

        Parkinson’s disease is a chronic and progressive disorder of the central nervous system that affects movement, muscle control and balance. This disease is caused by the deterioration of neurons within the area of the brain known as substantia nigra. When functioning properly, these neurons produce a vital brain chemical called dopamine, which serves as a messenger between areas of the brain such as the substantia nigra and the corpus striatum. This neurotransmitter coordinates balanced muscle movement, thus the lack of dopamine results in abnormal nerve functioning; causing a deficiency in the ability to control body movements.

As it develops gradually you may notice motor symptoms including tremors- a rhythmic shaking of a part of the body such as an arm or leg, muscle rigidity- increasing muscle stiffness, bradykinesia- slowness of movement and reflexes, and speech impediments. PD also has many underlying non-motor symptoms, some of which are mood changes- depression/anxiety, sleep disturbances, and even digestive problems. A great deal of research has focused on the physical impact of PD, however the significant emotional impact is not looked into as often. Many patients often face challenges such as battling depression, which contributes to poor concentration and confusion that can further develop into dementia. While trying to grasp the concept of loss of abilities and independence, patients become dependent of their caretakers, leaving them with a sense of apathy and lethargy.  This feeling of indifference is often more difficult to treat and may remain with them despite pharmacological intervention. (Waldberg, 2009) There are five general stages of the disease that are primarily justified by Parkinson specialists; used to target exact symptoms, in able to assign proper treatments. Stage I - Unilateral disease (affecting either left or right side of the body), Stage I.5 – Unilateral disease and axial (neck/back), Stage II – Mild bilateral (left and right) disease without impairment of balance, Stage II.5 – Mild bilateral disease with slight imbalance, lastly, Stage III – Moderate bilateral disease with stronger difficulty in balance.  (Marjama-Lyons & Shomon, 2003).

        Scientists in the late 1800s described Parkinson’s disease as a purely genetic disorder and till this day, the debate on whether Parkinson’s is simply genetic or environmentally derived still goes on. The disease was viewed as an inheritance for quite some time until the outbreak of viral encephalitis lethargica, a parkinsonian syndrome, during World War I. After this epidemic scientist started conducting more research for other possible environmental causes such as exposure to toxic chemicals in the workplace or common viruses amongst our civilization. It has been agreed that most cases of PD sprout from some fusion of nature and nurture — the interaction between a person’s underlying genetic make-up and his or her personal life activities and environmental exposures. “A simple way to describe this is that ‘genetics loads the gun and environment pulls the trigger’.” (Tanner, 2011). There are many factors when it comes to likeliness to obtain this disease, some examples would be: age, gender, ethnicity, hereditary, toxic environmental exposures and even geographical location. An increase in age is associated with an increased risk of PD, around age 60 or older is when it is more likely to develop. When it comes to gender it is more common for men, studies show that perhaps estrogen- the primary female hormone may protect dopamine cells from dying, and that it could also be an occupational effect since men have the tendency to pursue occupations that expose them to toxins that are casually linked to PD. Within the various ethnicities, there is a higher prevalence in countries where the majority of the population is Caucasian. “Recent studies suggest that several genes may have a role in determining individual susceptibility to this disease, and the degradative enzyme monoamine oxidase (MAO) has been implicated in the disease process.” (Markham & Breakefield, 1994).  These findings support the idea that the MAO genes may be among the hereditary factors that influence susceptibility of individuals to PD. Research has shown that you are also at higher risk if one of your close family members has had history of the disease. Prolonged occupational exposure (of twenty years or more) to a combination of heavy metals including iron, copper, lead and manganese has been reported to increase the relative risk of acquiring PD by ten times as much compared to those occupied in non-industrial areas.