Complexity Can Create Problems
Difficulties with the nervous system (either CNS or PNS) can lead to profound muscle dysfunction as well as cognitive, behavioral, and social disorders. While there are too many to explain in this section, some of the more familiar disorders are described.
Common nervous system disorders
Given the complexity of the nervous system, it’s not surprising that occasionally communication breaks down and neurological disorders result:
· Epilepsy is a condition that occurs when abnormal electric signals from the brain create convulsions, affecting the way the body operates. Such seizures can be relatively minor or can be life-threatening.
· Stroke is caused by bleeding in the brain or a blocked blood vessel, and is often the result of high blood pressure, diabetes, or problems of the circulatory system.
· Peripheral neuropathy is caused by nerve damage, particularly peripheral nerves (hence the name), and can cause numbness and tingling in parts of the body.
Parkinson’s Disease
Parkinson’s disease results from lack of dopamine production or from a failure to detect this essential CNS neurotransmitter. Typically manifesting in adults over 50 years of age, symptoms begin with motor dysfunction including tremors, stiffness, and problems with walking. These early symptoms eventually lead to cognitive and social difficulties such as dementia as the disease progresses.
There is no cure for Parkinson’s disease; much research has looked into disease prevention and management of the symptoms. Several studies have reported links between antioxidants (such as vitamin C) and the prevention of Parkinson’s disease; however, this remains unresolved.
For patients who exhibit a decrease in dopamine production, medications that allow the neurotransmitter a longer active life are effective at reducing the symptoms. Typically, when dopamine is secreted toward synapses, an enzyme called monoamine oxidase (MAO) breaks down dopamine. MAO inhibitors reduce the efficacy of the enzyme, prolong the active life of dopamine, and mimic the presence of greater amounts of dopamine.
Alzheimer’s Disease
Accounting for approximately 60–70 percent of dementia cases, Alzheimer’s disease is a neurodegenerative disorder that primarily affects adults over the age of 65. Although the cause is poorly understood, heredity is thought to play a large role in determining who contracts the disease.
Several hypotheses have tried to explain the cellular/molecular events that lead to the disease; however, the leading hypothesis focuses on the role of amyloid plaque proteins (APPs) and their extraneous accumulation in the area surrounding neurons. It remains unclear if APPs cause Alzheimer’s, since vaccines that remove the APP accumulations (plaques) do not reverse the dementia in these patients.
Initial symptoms of Alzheimer’s include short-term memory loss that, in time, leads to more severe cognitive disorders. Disorientation and problems with language can cause the individual to isolate himself or herself. Further advancement of the disease leads to loss of systemic bodily functions and death.
Accidental brain injury
Many injuries to the nervous system are caused by accidents and injuries. One of the most common of these is concussion, a brain injury that occurs with a sudden blow to the head (such as hitting your head against the steering wheel in a collision) and occasionally with a sudden blow to the body (such as being tackled during a football game). The brain moves abruptly (the Latin root of the word “concussion” literally means “to shake violently”) inside the skull. This can cause loss of consciousness, swelling of the brain, or bleeding. Most concussions are minor and cause no lasting harm, but repeated or serious concussions can lead to brain damage.
Attention Deficit Hyperactivity Disorder
A neurodevelopmental disorder in children, attention deficit hyperactivity disorder (ADHD) or attention deficit disorder (ADD) affects a child’s ability to focus attention for more than a few minutes on tasks with or without increased extraneous motor activity. These children are often identified once they begin socialized education (either preschool or primary school) because of their failure to stay on task and/or inability to sit quietly for any length of time. While some children diagnosed with ADHD or ADD simply may have not been socialized properly or taught acceptable behaviors at home, others do have a pathophysiological basis for these disorders and can benefit from counseling and medication. Stimulants are the most popular and effective means to treat children with ADHD or ADD, although this may not always be the best solution.
Autism
This disease begins to manifest itself in early childhood and can be seen in a delay in language development as well as social dysfunction. However, the most significant symptom is repetitive behaviors. These behaviors help in the distinction between autism and ADHD or ADD.
While many neuronal disorders have pathophysiological or chemical foundations, the underlying cause of autism isn’t well understood. One possibility is the malformation of synapses throughout the CNS. This delays or incorrectly relays signals throughout the nervous system.
Many media articles have suggested a relationship between childhood vaccinations and autism. To date, the link between the two has been widely discredited within the medical and scientific community.