types of dementia
This irreversible, progressive brain disorder is the most common cause of dementia. It accounts for an estimated 60 – 80 percent of dementia-related cases. The disease is named after Dr. Alois Alzheimer who, in 1906, took notice of a woman who died of what was thought to be a mental illness. Her symptoms were memory loss, language problems, and unpredictable behavior. After she died, he examined her brain and noticed differences in her brain tissue. Today, scientists continue to study the brain and the changes that occur due to Alzheimer’s disease.
Vascular dementia is a deterioration of mental capabilities caused by multiple strokes. These strokes cause injuries to the vessels which supply blood to the brain and as a result, may damage areas of the brain responsible for specific functions as well as produce similar symptoms of dementia. As a result, Vascular dementia may appear similar to Alzheimer’s disease. Vascular dementia is not reversible or curable. However, if the underlying condition is identified, then specific treatment may be used to modify the progression. Some risk factors that may increase the risk of stroke include high blood pressure, atrial fibrillation, diabetes, and high cholesterol. Symptoms of vascular dementia can begin suddenly and progress or subside during one’s lifetime.
Dementia with Lewy Bodies (DLB)
Lewy bodies are small round structures that form inside nerve cells. Considered one of the most common causes of dementia, DLB has many similarities to Alzheimer’s and Parkinson’s disease often making it difficult to diagnose. Common symptoms may include visual hallucinations, trouble sleeping, memory loss, confusion, motor impairments, tremors, and poor balance. There is no cure for DLB, but some symptoms can be controlled with medication.
Parkinson’s disease is a progressive disorder starting in the central nervous system, often resulting in a dementia similar to Lewy bodies or Alzheimer’s disease. These individuals lack dopamine, which is necessary in order for the central nervous system to control muscle activity. Initial symptoms include tremors, speech impediments, and motor difficulty. Though many people with Parkinson’s eventually develop dementia symptoms, how long that may take varies for each person. Potential risk factors for developing dementia include whether or not the individual develops any cognitive impairment or sleep behavior problems such as visual hallucinations and frequent nightmares.
Mixed dementia is a combination of more than one dementia occurring at the same time. The most common appear to be Alzheimer’s disease, Vascular dementia, and Lewy body dementia. Autopsy studies suggest that many people over the age of 80 may have had mixed dementia. Scientists are working to understand how the different dementias influence each other and what the best approach for treatment is.
Frontotemporal Dementia (FTD)
Frontotemporal dementia is characterized by the degeneration of nerve cells in the frontal and temporal lobes of the brain. This breakdown causes changes in personality and behavior, as well as difficulty with language and movement control. Individuals with FTD usually shows initial signs at an early age (around 60). Whereas some people decide rapidly over 2-3 years, others can live anywhere from 2-10 years. Symptoms of FTD vary from person to person as different parts of the brain are affected. There is no treatment or cure FTD. Types of FTD include Behavioral variant frontotemporal dementia, Primary progressive aphasia, and Pick’s disease.
Creutzfeldt-Jakob Disease (CJD)
A rare and fatal brain disorder which may be due to an abnormal form of protein called a prion.
This infected protein, which can possibly be inherited or transmitted through exposure, causes a domino effect throughout the brain. Initial symptoms may appear around age 60 and include difficulty with memory, behavior and coordination. Progression is usually rapid and expands to include mental deterioration, involuntary movements, blindness, and eventually coma.
Huntington’s disease is an inherited, progressive brain disorder caused by a genetic mutation in which specific nerve cells in the brain and spinal cord waste away. Researchers have identified a link with a defective gene on chromosome 4. Usually beginning during mid-life, symptoms include involuntary movements, intellectual decline, personality changes, memory loss, slurred speech, and psychiatric problems. There is no treatment for Huntington’s disease; however, movement and psychiatric symptoms can be controlled with medication.
Sources: Alzheimer’s Association National Institute of Aging Mayo Clinic