Cognitive decline in aging: memory, attention, and executive function

Cognitive Aspects of the Aging Process

The purpose of this work is to define cognition and to explain the effects of aging on the brain in relation to memory, attention, metacognition, effects on languaging and the effects of aging on the executive function and finally cognitive function in very old age. This will be inclusive of primary cognitive diseases found in aging adults such as dementia and Alzheimer's.

Medical science continues to discover more about aging with each passing year. Cognitive effects of aging are one element that the aging individual must face as well as something that family and friends of the individual will cope with at some point. Cognition is defined as "the mental process of knowing, thinking, learning, and judging." (Online Medical Dictionary, 2005) Therefore the elderly experienced "cognitive dysfunction" is defined as "disturbance to the mental processes of knowing, thinking, learning and judging." Disturbances or dysfunctions of this type are typically difficult to deal with both from the aging individual's point-of-view as well as from the point-of-view of friends and family members. Although a progressive decline in overall brain or cognitive function is a natural process of aging the loss of the ability to store and retrieve information from short-term memory, to employ abstract reasoning and to easily learn new information can be depressing to both the aging individual and those in their life.

Manifestations of the age-associated cognitive disorder may be in various forms including senility, loss of memory, Alzheimer's disease and dementia. Dementia is inclusive of diseases that involve nerve cell deterioration with loss in two complex behavior areas including language, memory, visual abilities, spatial abilities, and judgment.

Causes

Causes are listed as conditions that affect the brain resulting in dysfunction of the type of intellectual, psychological, and behavioral. Causes may be related medication side effects, substance abuse, metabolic disorders, neurological disorders, infections, trauma, toxicity factors, hormonal changes, tumors, depression, circulatory disorders, TIA's (transient Ischemic attacks), and Hemorrhagic Stroke.

Cognitive Aging and Working Memory

According to Professor David Shanks, "It is striking that general mental slowing appears to account for almost all of the aging effect on memory. But this 'reductionism' can be taken even further." Shanks relate that Baltes and Lindenberger (1997) show that most of the aging effect is eliminated when individuals differences in very basic visual and hearing capacities are controlled. In other words if the elderly person's hearing and eyesight were to be boosted or restored to the 'young' levels then their memory would be boosted simultaneously.

There has been considerable debate in this area. Salthouse (1996) holds that cognitive slowing is fundamental in providing an explanation in age-related declines on each of the remaining cognitive tasks. A third view holds that working memory capacity decreases cause decreases in cognitive performance with advancing age. (Craik & Byrd, 1982). A mental energy that is available to the person in managing formation in a state of consciousness such as storing, retrieving, processing and manipulating information is what is known as working memory. Another view held by Hasher and Zacks (1988) is that age-related working memory declines are not representative of a capacity decrease but instead the working memory has become littered with information that is irrelevant due to the decrease in the ability to control the contents of the working memory.

Long-Term Memory

In the attempt to understand the interrelationship that exists among the constructs of sensory functions, speed and working memory in the prediction of the higher order cognitive processes of long-term type memory a study was conducted with interested in whether there were differences existing in the way visuospatial and verbal processes were organized in young and old adults. Suggestions were that they were "distinct, differentiated stores." Tested were lifespan samples of 345 adults ranging from age 20 to 95 with each individual completing a series of cognitive tasks. Results show decline in the rate of speed of processing, visuospatial and verbal working memory and visuospatial and verbal long-term memory were the same, regardless of modality. "(Park, 2002)

Environmental Support Indications

Cognitive aging researchers have considered the notion that "age-related deficits can be repairs by some type of environmental support"(Craik & Byrd, 1982; Craik & Jennings, 1992). According to Park (2002) evidence does exist suggesting that "when tasks require less self-initiated processing, such as in recognition compared to recall, age differences in memory become smaller. Further, when preexisting associations can be relied on by older adults the age differences in relation to recall grow much smaller. (Park, 2002 citing Park, Smith, Morrell, Puglisi & Dudley, 1990)

Health-Related Cognitive Function Impairment

It was discovered by Perimutter & Nyquist (1990) that increased age has been found to be associated with lower self-reported health status which may be a reflection of the overall capabilities of the biological system of the aging individual. Bazargan and Barbre (1994) found that older adults who report health to be poorer report having more memory problems as well which indicates that decreases in health also lead to decreases in memory and memory related problems. (Earles, et al., 1997)

Changes in Hormonal Levels Associated with Cognitive Decline

A study at the Julius Center for Health Sciences and Primary care in the Netherlands was conducted in relation to Endogenous sex hormone levels and cognitive function in aging men to determine whether endogenous sex hormone levels are associated with cognitive function. 400 men living independently were assessed in a population-based cross-sectional study. The results in the study show that "Curvilinear associations were observed between T. And memory performance and processing capacity and speed suggesting that optimal sex hormonal levels exist for cognitive tasks and are explained by linear associations in the oldest age category." (Muller, et al., 2005)

Medical Treatments Available

Medical treatments include several experimental 'Nootropic' agents which may provide improvements in cognitive function. Nootropic drugs are used for the facilitation of learning and memory. There are no standard drug therapies in existence at this time for treating cognitive disorders in the elderly. Age-related cognitive decline or ARCD is partly related to Alzheimer's disease. ARCD has a gradual onset. Rapid mental deterioration in the elderly is not natural such as is witnessed in Alzheimer's disease cases.

Dietary Changes

Dietary changes are thought to improve cognitive performance in the elderly. For example a British study found that higher levels of coffee consumption improved cognitive performance in the aging individual. Other studies indicate that diets which are high in antioxidant rich foods are beneficial in slowing the progression of ARCD. Vitamin C and beta-carotene levels in the blood have been associated with better performance in memory functions in those over the age of 65 years old.

Lifestyle Changes

Those who smoke cigarettes and have high levels of educational attainment seem to have unexplained protection against ARCD. A randomized controlled clinical trial resulted in findings that group exercise contains beneficial effects on physiological functioning and cognitive functioning as well-being in aging individuals. Findings at the end of the trial showed that exercisers show 'significant improvements in reaction time, memory span, and measures of well-being when compared with controls" (Vitacost, 2005)

Nutritional Aids in Combating Cognitive Dysfunction

Clinical trials indicate that acetyl-L-carnitine delays onset of ARCD as well as improving cognitive function in elder individuals on an overall basis. 1,500 milligrams per day was given to elderly subjects in a clinical rial with findings that after 90 days significant improvements in memory, mood and responses to stress were noted and these favorable effects lasted up to 30 days after discontinuation of treatment. (Vitacost, 2005)

Phosphatidylserine, a substance derived from bovine brain phospholipids has been shown to:

Improve memory

Improve cognition

Improve mood

In two placebo-controlled trials elderly patients received 300 milligram doses per day of the phosphatidylserine in an unblinded trial of ten elderly females with depressive disorders. The phosphatidylserine produced "consistent improvement in depressive symptoms, memory, and behavior after 30 days of treatment. In another double blind trial of 494 elderly patients found that a 300 milligram dosage per day had produced 'significant improvements in behavioral and cognitive parameters after three and six months. The medication vinpocetine given in 30 and 60 milligram per day doses was found in a double-blind trial to improve symptoms of dementia in patients with various brain disease as well as those with dementia and cognitive decline.

Vancarnine which is a natural unmodified compound in Vinca minor was tested on dementia patients in a large double-blind trial which found that 60 milligrams per day of vincarnine was more effective than the placebo for improvement of cognitive function in those with Alzheimer's or dementia which is associated with vascular brain disease.

Summary

Many cognitive dysfunctional symptoms are noted in the elderly and aging individual. However the more active the elderly individual's mind stays and the more involved with everyday life that the elderly individuals allow themselves to be then the more likely that they will retain their cognitive level functioning longer. Much has gone into research both in the ways of time, funding, resources and commitment on the part of researchers. Although much more is know about cognitive decline than even five or ten years ago there is still much that is left unanswered in relation to cognitive decline. Furthermore there is not established treatment of cognitive aging disorder although there are tested medications, nutrients, and techniques that appear to be effective in combating the onset of the disease.

Conclusion

There is much room for expanding studies in relation to cognitive aging and further research is needed in this area. There are also many oddities in the findings in research that is foregoing which needs to be clarified through more research and findings in evidence. Finally, there does appear to be indications that gender-based differences in cognitive aging and dysfunction must be addressed in the treatment of cognition slowing in aging affirming the need for further research in this area of health and psychological care for the elderly individual.