By: Amanda Charlton-Fryer, Psy.D.

Alzheimer’s disease is the most prevalently diagnosed type of dementia (Barr, Benedict, Tune, & Brandt, 1992; Vanderploeg, 2000). Currently four million Americans are thought to be affected with this disease (Alzheimer’s, Memory, & Acetylcholine, n.d.; Litchtenberg, et al., 2003; National Institutes of Health, 2004). Additionally at least 360,000 individuals are newly diagnosed each year (National Institutes of Health, 2004). The impact is greater in the very old, with nearly 50 percent of those age 85 or older afflicted with the disease (Alzheimer’s, Memory, & Acetylcholine, n.d.).

Risk Factors
Several risk factors exist with regard to Alzheimer’s disease. According to epidemiological studies, it is postulated that head trauma, low level of education, increased age, and family history of dementing illness raise the likelihood that an individual will develop Alzheimer’s disease (Litchtenberg, et al., 2003; Mace & Rabins, 1999). Those who live to a very old age are at increased risk for developing the disease (Mace & Rabins, 1999). Medical conditions also play a role. For example, high cholesterol is a known risk factor for Alzheimer’s disease (Litchtenberg, et al., 2003; National Institutes of Health, 2004). Another risk factor for Alzheimer’s disease is Type II diabetes (Draper, 2004; Litchtenberg, et al., 2003; National Institutes of Health, 2004), often controllable with dietary changes. Other modifiable factors, such as smoking, are linked to Alzheimer’s disease (National Institutes of Health, 2004). Some researchers believe that women are at higher risk for developing Alzheimer’s disease (Mozes, 2005). However, this may be due to the fact that women live longer and make up more of the population of those living to advanced age (Mace & Rabins, 1999).

Diagnosis
According to the NINDS-ARDA criteria, the diagnosis of Alzheimer’s disease is often made after ruling out other possible causes of dementia. Since the definitive diagnosis can only be made upon autopsy, Alzheimer’s disease is diagnosed as “possible” if there is a progressive decline in a single cognitive sphere (usually memory), if there is an atypical course of presentation of dementia, or another illness sufficient to cause dementia but not considered the cause of dementia (Rapoport, 2000). The diagnosis is deemed “probable” if there is a progressive deficit in memory with an additional cognitive defect present and no other possible cause of dementia (Rapoport, 2000). The label of “definite” Alzheimer’s disease is given to those with a history of dementia and a postmortem autopsy revealing abnormalities in the brain, which include critical densities of senile plaques and neurofibrillary tangles with paired helical filaments (Rapoport, 2000).

Disease Progression
It has been postulated that Alzheimer’s disease may actually have a preclinical period. During this time, there is an early onset of changes, typically memory impairment, followed by a period of stability or plateau for a few years until diagnosis; then the characteristic steady decline in functioning begins (Backman, Jones, Berger, Laukka, & Small, 2005; Haxby, Raffaele, Gillette, Schapiro, & Rapoport, 1992). Alzheimer’s disease is typically characterized by a gradual onset of symptoms, which occurs in late life and increases with age (Marin, et al., 2002). Disease progression often follows a gradual decline in functioning that continues for 7-10, with some as long as 20, years before death (Mace & Rabins, 1999; National Institutes of Health, 2004).

Symptoms
Alzheimer’s disease typically is not detected until around the age of 65 (Alzheimer’s, Memory, & Acetylcholine, n.d.). The first sign of Alzheimer’s disease is usually forgetfulness (Alzheimer’s Association, 2004). In the beginning stages, those with dementia are often able to hide their symptoms, such as memory loss. Individuals often begin making lists or finding other ways to conceal difficulties (Mace & Rabins, 1999).

In those with Alzheimer’s disease, decline in functioning was estimated to occur first in episodic memory, then psychomotor speed, semantic memory, and visuospatial functioning (Almvist & Backman, 1993). As the disease progresses, symptoms include dysfunction in language, reasoning, and understanding (National Institutes of Health, 2004). However, individuals may be unwilling to admit that they can no longer handle complex daily tasks such as driving (Mace & Rabins, 1999) and managing finances. The later stages of Alzheimer’s disease are quite devastating for both the individual and their loved ones. With the progression of the disease there is a loss of ability to perform tasks of daily living. One eventually becomes completely dependent on others to provide care.

When the brain is damaged, changes in behavior, emotionality, personality, and reasoning can occur (Mace & Rabins, 1999). Early in Alzheimer’s disease, personality and social skills remain in place (Mace & Rabins, 1999). As memory and ability to learn slowly fade away (Mace & Rabins, 1999), those with Alzheimer’s disease may experience behavioral symptoms such as apathy, irritability, aggression (Stout, Wyman, Johnson, Peavy, & Salmon, 2003).

Although Alzheimer’s disease may be mistaken for normal aging in its earliest stages, it is very different. Whereas in normal aging one experiences a loss of some cells in the brain, Alzheimer’s disease and other forms of dementia are due to a process in which nerve cells stop functioning, lose connections to one another, and die, resulting in a large loss of neurons (National Institutes of Health, 2004).

References:

Almkvis, O., & Backman, L. (1993). Progression in Alzheimer’s disease: sequencing of neuropsychologicaldecline. International Journal of Geriatric Psychiatry, 8, 755-763.

Alzheimer’s Association. (2004). Alzheimer’s disease fact sheet. [Brochure].

Alzheimer’s, Memory, and Acetylcholine. (n.d). Retrieved on July 14, 2005, from http:www.psyweb.com/Documents/00000003.jsp.

Backman, L., Jones, S., Berger, A.K., Laukka, E.J. (2005). Cognitive Impairment in preclinical Alzheimer’s disease: A meta-analysis. Neuropsychology, 19(4), 520-531.

Barr, A., Benedict, R., Tune, L., & Brandt, J. (1992). Neuropsychological differentiation of Alzheimer’s disease from vascular dementia. International Journal of Geriatric Psychiatry, 7, 621-627.

Draper, B. (2004). Dealing with dementia: A guide to Alzheimer’s disease and other dementias. Crows Nest, Australia: Allen & Unwin.

Haxby, J.V., Raffaele, K., Gillette, J., Schapiro, M.B., & Rapoport, S.I. (1992). Individual trajectories of cognitive decline in patients with dementia of the Alzheimer type. Journal of Clinical and Experimental Neuropsychology, 14(4), 575-592.

Litchtenberg, P.A., Murman, D.L., & Mellows, A.M. (Eds.). (2003). Handbook of dementia psychological, neurological, and psychiatric perspectives. Hoboken, NJ: John Wiley & Sons, Inc.

Mace, N.L., & Rabins, P.V. (1999). The 36 hour day: A family guide to caring for persons with Alzheimer’s disease, related dementing illness, and memory loss in later life (3rd ed.). Baltimore: John Hopkins Press Health Book.

Mozes, A. (2005, June 20). Worldwide Alzheimer’s Care Carries Staggering Costs. Health Day News, Retrieved July 25, 2005, from http://www.medicinenet.com/script/main/art.asp?articlekey=47683.

National Institutes of Neurological Disorders and Stroke & National Institutes of Health. (2004). The Dementias: Hope Through Research (NIH Publication Number 04-2252).

Rapoport, S.I. (2000). Anatomic and functional brain imaging in Alzheimer’s disease. Pscyhopharmacology- The Fourth Generation of Progress.

Stout, J.C., Wyman, M.F., Johnson, S.A., Peavy, G.M., & Salmon, D.P. (2003). Frontal behavioral syndromes and functional status in probable Alzheimer’s disease. American Journal of Geriatric Psychiatry, 11(4), 1-4

Vanderploeg, R.D. (2000). Clinician’s guide to neuropsychological assessment (2nd ed.). Mahwah, NJ: Lawrence Erlbaum Associates, Inc.

Information extracted from Charlton, A. (2006) Logical Memory and Visual Reproduction Recognition Performance in the Differential Diagnosis of Alzheimer’s Disease and Vascular Dementia.