The earliest known record of the study of Parkinson’s Disease is mentioned in James Parkinson’s “Essay on the Shaking Palsy”. The article describes the most common features of the disease which remain as the standard by which other types of parkinsonism are compared. The disease is mainly characterized by trembling of the limbs, muscular stiffness, and slow body movement. In addition, individuals suffering from the disease exhibit the following: standing in a stooped posture; walking in short, shuffling steps, and speaking softly in a rapid and even tone. In most cases, 60 to 80 percent of an individual’s dopaminergic neurons – dopamine-producing cells of the body – are already non-functional by the time Parkinson’s disease has been diagnosed.
The mechanism which causes Parkinson’s disease remains unknown. Its pathological classification describes it as a systemic degeneration of the brain which targets specific cells in the brain. In 1908 Dr. Frederick Lewy discovered abnormal structures in the brain associated with Parkinson’s Disease. Called Lewy bodies, these structures are not found in other forms of parkinsonism. It has been theorized that a premature aging process, unknown nutrient deficiency or toxin may be causing the deterioration of the substantia nigra.
Tremors are the most common of Parkinson’s disease, as observed in 50 percent of reported cases. It is the involuntary rhythmic movement of a body part which may occur during rest or when an individual performs a certain movement or action. When the trembling occurs in the middle of a movement, it is classified as an action tremor. However, this does not show as a sign of the disease (Christensen, 2005). Body tremors usually affect the arms and legs, but may also be observed on the lips, tongue, jaw, abdomen, and chest. The trembling action only occurs when the body part concerned is at rest, thus it is described as a resting tremor (Duvoisin & Sage, 2001). In its advanced stages, Parkinson’s disease may also cause postural or action tremors (Schapira, 2010). Rest tremors usually start at the hands or feet, progressing until all four limbs are affected. Since rest tremors disappear once the body part affected starts to move, it does not interfere with an individual’s ability to perform usual activities such as walking or holding objects (Sharma & Richman, 2005). Jankovic’s (2008) review of existing literature on Parkinson’s disease show that 69% of patients had rest tremor at the onset of the disease. Meanwhile, 9% of the patients lost their tremors at later stages. On the other hand, 11% of patients reported not experiencing tremors. However, another study involving autopsies among victims of Parkinson’s disease revealed that all patients had experienced tremors at some point. Minen and Louis (2008) performed a study on clinical correlates among 53 patients diagnosed with Parkinson’s disease. Analysis of the data collected revealed that 100% of the patients had rest tremors. In addition, the data also show that majority of patients with rest tremors were male. Muscular Rigidity Muscular stiffness among patients with Parkinson’s disease is characterized by a constant and uniform resistance to limb manipulation. This type of stiffness in the muscles is called plastic rigidity wherein the patient’s muscles lose their ability to go back into a relaxed state even when the muscle is at rest (Duvoisin & Sage, 2001). Normally, muscle action involves the contraction and relaxation of specific muscle pairs. One muscle contracts while the other muscle relaxes. However, in