The Neurobiology of Parkinson's Disease
In neuroscience it is assumed that the central nervous system governs and defines all aspects of behavior (Grobstein, 1998). Therefore, the brain, the hub of the central nervous system, is responsible for integrating all sensory and motor patterning. To understand the mechanisms of neurobiology it is often useful to observe the nervous system at the level of the neuron. Integration and communication between neurons is facilitated by neurotransmitters, chemicals which act as intermediaries at the synaptic gap (Delcomyn, 1998). Many behavioral disorders have a neurochemical basis, oftentimes associated with abnormal neurotransmitter activity. These abnormalities are thought to stem from interactions between genetics and the environment. One of these disorders is Parkinson's Disease, a progressive neurodegenerative disease which is characterized by a deficit in the neurotransmitter dopamine (NHGRI, 1998).
Parkinson's Disease affects more than a million Americans a year and is distributed equally geographically, in both men and women, and between socio-economic classes (PD Web, 1998). Although the probability of developing the disease is somewhat equal in all populations, recent studies have shown that African-Americans and Asians are less likely to exhibit Parkinson's symptoms than those of European descent (PD Web, 1998). It was first formally identified by British physician James Parkinson in 1817 as "The Shaking Palsy", however, it is thought that the disease has been around for thousands of years. Described as early as 5000 B.C. in the Indian Ayurvedic medicinal tradition and in the Nei Jing, the first Chinese medical text 2500 years ago, Parkinson's disease has been a constant challenge to public health around the world (NHGRI, 1998).
With increasing concern over the state of the nation's health care, it is important to realize the impact of Parkinson's Disease. The National Parkinson's Foundation estimates that each PD patient pays $2500 a year on medicines alone. When accounting for Social Security and nursing home payments, Parkinson's Disease costs over $5.6 billion annually to the nation (PD Web, 1998). Despite the high occurrence of Parkinson's, it is still not always recognized as a significant medical problem. The symptoms are often ignored in the elderly because they are thought to be part of the natural process of aging (PD Web, 1998). Symptoms include tremors in hands, arms, legs, jaw, and face; slowness of movement, or bradykinesia, and difficulties in balance and coordination. As the chronic disease progresses, PD patients may have difficulty with simple tasks, such as walking and talking (PD Web, 1998). Much of the oversight of PD in medical research, and of other neurodegnerative diseases associated with elderly populations, like Alzheimers, could be a reflection of a dismissive attitude towards the aging process in the medical community and American culture.