Neurologic Conditions
Parkinson's Disease
More than one million people in the United States suffer from Parkinson’s disease. This neurodegenerative condition most often occurs after the age of 60 and is slightly more common in men.
Parkinson’s disease affects an area of the brain called the substantia nigra causing these brain cells to die or become impaired. These neurons produce dopamine, which is the chemical messenger that allows the body's muscles and motor system to function normally. The loss of dopamine neurons results in the inability to control movements properly.
While there are many possible symptoms of Parkinson’s disease, the four cardinal features include:
Tremor at rest - shaking
Bradykinesia - slowness of movement
Rigidity - stiffness
Postural instability - impaired balance
The earliest motor symptoms typically appear on one side of the body and may include only one or two of the above; no one person develops all of the possible symptoms. Early symptoms are often subtle, and may include small cramped handwriting, softening of the voice or reduced arm swing, among others.
Loss of sense of smell may be another very early sign of Parkinson’s disease and appears to precede the motor symptoms by many years. IND is conducting research to better understand if loss of the sense of smell may be a precursor for Parkinson’s disease.
Parkinson’s disease is a slowly progressive condition. Both the rate of progression and the symptoms are variable from person to person. Current research efforts at IND, are focused on early detection prevention and, slowing progression of the disease as well as improving symptomatic treatment.
Making a diagnosis of Parkinson’s disease currently depends on the clinical judgment of experienced physicians. The research team at IND has been a leader in the development of imaging tests that provide information about the integrity of the dopamine system. These imaging tools provide information that compliments the clinical evaluation and leads to a more accurate diagnosis.
Alzheimer’s Disease
Alzheimer’s disease is a progressive brain disorder that affects areas of the brain involved in memory, intelligence, judgment, language, and behavior. According to statistics provided by the Alzheimer’s Association, it is estimated that 5.3 million Americans suffer from Alzheimer’s disease. The risk for developing Alzheimer’s disease increases with age and about one in 8 people over the age of 65 is affected by Alzheimer’s disease. It is the most common form of mental decline or dementia in older adults.
Alzheimer’s disease may present with a variety of symptoms, however the most common symptom is memory loss. People closest to the individual affected by Alzheimer’s disease may notice subtle changes that may not be apparent to others or to the individual himself.
The following is a list of typical symptoms experienced in Alzheimer’s disease:
Memory loss that interferes with day-to-day function
Difficulty with planning or problem solving
Changes in personality or mood
Disorientation or confusion with time and space
Difficulty coming up with words or speaking
Decreased ability to make decisions or poor judgment
Social withdrawal
The area of the brain responsible for forming new memories is usually the first to be affected. A number of studies indicate an accumulation of protein deposits called beta-amyloid in the brain of individuals with Alzheimer’s disease. Formation of another protein called tau results in tangles inside the dying brain cell. These protein deposits interfere with the normal function of the brain eventually causing the symptoms recognized as Alzheimer’s disease. It appears that amyloid may be present in the brain many years before any signs or symptoms of dementia.
Making the diagnosis of Alzheimer’s disease can be difficult requiring multiple tests to exclude other possible diagnoses. Being able to recognize Alzheimer’s disease early in the process is becoming increasingly important as medications to slow the progression of the disease are made available.
Autopsy remains the only conclusive way to determine whether beta-amyloid is present in the brain. At IND advanced brain imaging techniques are being developed and evaluated to identify beta-amyloid in the brain. IND also conducts clinical trials involving medications aimed at decreasing the progression of Alzheimer’s disease. These medications have the potential to reduce the amount of beta-amyloid deposits in the brain. If these medications are administered early in the disease there is the highest potential of restoring brain function and reducing disease progression.
Development of brain imaging techniques for early and accurate diagnosis combined with the use of medications to reduce disease progression hold promise for improving the prognosis for Alzheimer’s disease.
Huntington’s Disease
Huntington’s disease is an inherited, neurodegenerative and progressive brain disease that currently affects approximately 15,000 Americans. Most frequently the symptoms of HD occur between the ages of 30 and 50.
A major breakthrough was made in 1993 when the gene associated with Huntington’s disease was discovered. It is a familial disease. Each child of a parent with the huntingtin gene has a 50-50 chance of inheriting the gene. At least 150,000 Americans have a 50% risk of carrying the gene and developing the disease. This defect ultimately causes the death of nerve cells in the brain resulting in the following symptoms:
abnormal facial movements
abnormal body movements
mood swings
depression
irritability
slurred speech
difficulty walking
personality changes
loss of mental capacity (dementia)
The abnormal facial and body movements are often described as uncontrollable dance-like, quick jerking movements. These movements are sometimes referred to as Huntington's chorea because "chorea" means dance. It is important to realize that there is wide variation in symptoms and affected individuals may experience only a few of the symptoms listed here.
Over the past 25 years, through the efforts of voluntary organizations, the scientific community, and affected families, this disease has become more widely known and understood. Although treatment for Huntington’s disease is limited, there are medicines which have been shown to be helpful in reducing individual symptoms, such as chorea. However, none as yet can change the course of the disease.