The Different Types of Alzheimer's

There are two different types of Alzheimer's Disease: Late Onset Alzheimer's and Early Onset Alzheimer's. The symptoms of these different types of Alzheimer's Disease are similar, but different groups are at risk for each type. Common symptoms of Alzheimer's Disease include disorientation, memory loss, trouble with problem solving or spatial reasoning, poor judgment and social withdrawal. Below is a brief breakdown of the differences and risk factors for different types of Alzheimer's Disease.

Late Onset Alzheimer's Disease

Late Onset Alzheimer's Disease is the most common type of Alzheimer's Disease, and usually affects people who are 65 years or older. You have a higher risk of developing Late Onset Alzheimer's Disease once you reach age 85: approximately half of everyone over age 85 shows symptoms of Alzheimer's Disease. The causes of this type of Alzheimer's Disease are not fully understood. Although Late Onset Alzheimer's Disease is not always hereditary, you are more likely to develop this type of Alzheimer's if someone else in your family has also been affected. Other risk factors for this type of Alzheimer's Disease include diabetes, head injuries, heart disease and high blood pressure. According to the Alzheimer's Association, possible links to Alzheimer's Disease from aluminum, aspartame, dental fillings or flu shots have not been scientifically verified.

Early Onset Alzheimer's Disease

Early Onset Alzheimer's Disease, also called Younger Onset Alzheimer's Disease, is a less common type of Alzheimer's Disease. The symptoms of Early Onset Alzheimer's Disease are essentially the same as the symptoms of Late Onset Alzheimer's Disease, but individuals with Early Onset Alzheimer's may experience more muscle twitches or muscle spasms. People with Early Onset Alzheimer's Disease begin to develop symptoms before age 65, often as early as their 40s or 50s.

The causes of Early Onset Alzheimer's Disease are not clearly defined, but approximately half of all cases are inherited. Early Onset Alzheimer's may be the result of a genetic mutation that is passed down through families; if so, this type of Alzheimer's may be called Familial Alzheimer's Disease. If you have a parent or grandparent with Early Onset Alzheimer's Disease, you are at risk of developing Early Onset Alzheimer's Disease. There are three particular genes associated with Early Onset Alzheimer's Disease, and genetic testing can be done to determine if you have inherited the mutated gene. Not everyone who inherits the gene will be affected by the disease. Individuals with Down's Syndrome are also at risk for Early Onset Alzheimer's Disease because Down's Syndrome is related to an abnormality of one of the same genes associated with Early Onset Alzheimer's Disease.

Other Types of Dementia

Although Alzheimer's Disease is the most common condition associated with memory loss, disorientation and declining mental abilities, other types of dementia may have similar symptoms to Alzheimer's Disease. These include Frontotemporal Dementia, Huntington's Disease, Parkinson's Disease and Vascular Dementia. Some of dementia may appear before 65, and their progress may be quicker than either of the types of Alzheimer's Disease.

Sources:

Alzheimer's Association; Risk Factors http://www.alz.org/alzheimers_disease_causes_risk_factors.asp

Genetics Home Reference; Alzheimer's Disease; 2008 http://ghr.nlm.nih.gov/condition=alzheimerdisease

Mayo Clinic; Early-Onset Alzheimer's: When Symptoms Begin Before 65 http://www.mayoclinic.com/health/alzheimers/AZ00009

Thomas D Bird, MD; Early-Onset Familial Alzheimer Disease http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=gene&part=alzheimer-early

US News and World Report; Types of Alzheimer's Disease; 2006 http://health.usnews.com/usnews/health/brain/alzheimers/alz.about.typesstages.types.htm

WebMD; Types of Alzheimer's Disease; 2009

http://www.webmd.com/alzheimers/guide/alzheimers-types