Alzheimer's disease starts in the brain and leads to changes in functioning and behaviors. Brain imaging and genetic studies give insight to the way the disease starts and how it progresses through the body. Such scientific advances are beneficial to the diagnosis and treatment of the disease.
Effects
Alzheimer's disease leads to the deterioration of the brain which causes impairments in functioning, according to John Santrock in his book "A Topical Approach to Lifespan Development." Specifically, as Alzheimer's disease progresses, the person affected gradually experiences declines in memory function as a result of changes in the brain. Changes in brain function affect bodily functions such as urination, as evidenced by the incontinence commonly experienced by Alzheimer's patients, Santrock explains.
The decline becomes so severe that psychosis is common among people in the mid to severe stages of Alzheimer's disease, according to S. Gauthier and colleagues in 2008 in the "International Journal of Geriatric Psychiatry." These changes in brain function also affect patients' ability to have rational thought and reasoning. The physiological brain changes impact the way a person with Alzheimer's disease feels overall. Specifically, they are more prone to feeling aggressive and agitated, according to Gauthier.
Prevalence
Alzheimer's disease is the most prevalent type of dementia-causing disease, affecting more than 20 million people globally, according to Michel Goedert and Maria Spillantini in the November 2006 issue of "Science." Late-onset is defined as experiencing the disease at age 65 or older, according to Santrock. Early onset relates to the prevalence of the disease prior to age 65. Early-onset is rare, however, occurring in approximately 10 percent of all Alzheimer's cases between the ages of 30 and 60.
Mechanism
Alzheimer's is linked to abnormal deposits of protein in the brain. This is also the case for other neurodegenerative disorders, not just Alzheimer's, according to Goedert and Spillantini. In some cases, defective genes are responsible for signaling the changes that result in toxic protein formation. Therefore, genetic factors influence the path of Alzheimer's progression.
Diagnosis
Early diagnosis of Alzheimer's disease involves the measurement of brain structures through brain imaging technology, as Olivier Querbes and colleagues note in the August 2009 issue of "Brain." Specifically, loss of cortical thickness is an indicator of the prevalence of the disease. Other types of diagnostic tools that measure cognitive performance may cause some patients to go undiagnosed. For example, people with a higher education may have good mental strategies for coping with brain damage and would therefore not score a certain low level of cognitive proficiency to meet diagnostic criteria for the disease.
Treatment
Although lifestyle factors tend to enhance health and functioning in older ages, the affect of lifestyle factors on Alzheimer's disease is unclear, as discussed by Nikolaos Scarmias, M.D. and colleagues in August 2009 in "The Journal of the American Medical Association." Specifically, the authors note that the effects of exercise and diet on Alzheimer's disease are unclear. Some studies have shown that exercise slows down cognitive decline in patients with Alzheimer's while other studies have not found exercise to be related, Scarmias notes. Prescription medications have also been found to be useful for Alzheimer's disease management, according to Gauthier.
References
- "The Journal of the American Medical Association"; Physical Activity, Diet, and Risk of Alzheimer Disease; Nikolaos Scarmias, M.D. et al.; Aug. 12, 2009
- "International Journal of Geriatric Psychiatry"; Improvement in Behavioural Symptoms in Patients With Moderate to Severe Alzheimer's Disease by Memantine: A Pooled Data Analysis; S. Gauthier, H. Loft, & J. Cummings; 2008
- "Science"; A Century of Alzheimer's Disease; Michel Goedert & Maria Grazia Spillantini; Nov. 3, 2006
- "A Topical Approach to Lifespan Development"; John W. Santrock; 2007
- "Brain"; Early diagnosis of Alzheimer's disease using cortical thickness: impact of cognitive reserve; Olivier Querbes et al.; August 2009
