Diseases of the Nervous System
Epilepsy is a chronic condition defined by abnormal activity in the brain that leads to recurrent seizures. About 50,000,000 people worldwide have epilepsy.
Cause: Abnormal firing of neurons in the brain can be caused by genetics, a tumor in the brain, or damaged brain tissue that interrupts how signals are transferred between neurons. However, the causes of many types of epilepsy are unknown. There are several triggers that can set off seizures in people with epilepsy, such as reading, flashing lights, stress, alcohol, and lack of sleep.
Symptoms: Recurring seizures are the main symptom of epilepsy. Many seizures involve a partial loss of consciousness or control of bodily functions, and some episodes may be more severe than others.
Treatment: There are many drugs approved to treat epilepsy, most of which work by reducing the occurrence of seizures. For some people, a diet with high proportions of fats and proteins and low amounts of carbohydrates (called a ketogenic diet) can reduce the occurrence of seizures. Another treatment for epilepsy is electrical stimulation of the nerves in the brain. Some people can control seizures by learning to avoid the triggers for seizures. In extreme cases, surgery can be performed to remove the part(s) of the brain with irregular activity.
Parkinson’s disease is a neurodegenerative movement disorder that begins late in life, commonly after 50 years old.
Cause: The underlying problem is the progressive death of neurons that produce the neurotransmitter dopamine. The trigger(s) that cause the death of these neurons is unknown.
Symptoms: People with Parkinson’s disease develop problems with motor coordination, like tremors while resting, and problems with posture and walking. Their limbs can also appear rigid from joint stiffness. Some patients may experience problems with cognition, such as poor memory and slower problem solving skills.
Treatment: There is no cure for Parkinson’s disease. At best, the symptoms can be alleviated with drugs, but these medications can cause side effects. One medicine called levodopa can help motor coordination in some people because it replaces the body’s dopamine. Other drugs used to treat the symptoms of Parkinson’s disease are called dopamine agonists, which are molecules that behave like dopamine in the body. Sometimes brain “pacemakers” are surgically implanted to send signals to specific parts of the brain, compensating for the reduced number of signals normally stimulated by dopamine.
Multiple sclerosis is an autoimmune disease affecting the neurons in the brain and spinal cord, commonly diagnosed between 20 and 40 years of age.
Cause: In this disease, inflammation damages the myelin sheath, which is the insulating covering that wraps around neurons. When this sheath is disrupted, the electrical signals traveling down the axons slow down or stop altogether.
Symptoms: This disease is characterized by symptoms that are episodic with each episode lasting days or months and periods of remissions (decreased or no symptoms) in between. Because of the disrupted nerve signals, muscle function is diminished resulting in a multitude of symptoms since so many bodily processes rely on proper signaling between neurons and muscles. Therefore, patients experience loss of balance, spasms, numbness and difficulty moving. Since urination and defecation are controlled by many nerves and muscles, patients may experience loss of bladder control or changes in their bowel movements. Impaired vision, trouble speaking and swallowing may result from disrupted nerve signals to the eyes, mouth and throat. Disruption of nerve signals in the brain lead to decreased memory, decision-making, and problem-solving skills.