aging and memory loss
Age-related memory loss, sometimes described as "normal aging" is qualitatively different from memory loss associated with types of dementia such as Alzheimer's disease, and is believed to have a different brain mechanism.
Mild cognitive impairment (MCI) is a condition in which people face memory problems more often than that of the average person their age. These symptoms, however, do not prevent them from carrying out normal activities and are not as severe as the symptoms for Alzheimer's disease (AD). Symptoms often include misplacing items, forgetting events or appointments, and having trouble finding words.
According to recent research, MCI is seen as the transitional state between cognitive changes of normal aging and Alzheimer's disease. Several studies have indicated that individuals with MCI are at an increased risk for developing AD, ranging from one percent to twenty-five percent per year; in one study twenty-four percent of MCI patients progressed to AD in two years and twenty percent more over three years, whereas another study indicated that the progression of MCI subjects was fifty-five percent in four and a half years. Some patients with MCI, however, never progress to AD.
Studies have also indicated patterns that are found in both MCI and AD. Much like patients with Alzheimer's disease, those suffering from mild cognitive impairment have difficulty accurately defining words and using them appropriately in sentences when asked. While MCI patients had a lower performance in this task than the control group, AD patients performed worse overall. The abilities of MCI patients stood out, however, due to the ability to provide examples to make up for their difficulties. AD patients failed to use any compensatory strategies and therefore exhibited the difference in use of episodic memory and executive functioning.
Normal aging is associated with a decline in various memory abilities in many cognitive tasks; the phenomenon is known as age-related memory impairment (AMI) or age-associated memory impairment (AAMI). The ability to encode new memories of events or facts and working memory shows decline in both cross-sectional and longitudinal studies. Studies comparing the effects of aging on episodic memory, semantic memory, short-term memory and priming find that episodic memory is especially impaired in normal aging; some types of short-term memory are also impaired. The deficits may be related to impairments seen in the ability to refresh recently processed information.
Source information is one type of episodic memory that suffers with old age; this kind of knowledge includes where and when the person learned the information. Knowing the source and context of information can be extremely important in daily decision-making, so this is one way in which memory decline can affect the lives of the elderly. Therefore, reliance on political stereotypes is one way to use their knowledge about the sources when making judgments, and the use of metacognitive knowledge gains importance. This deficit may be related to declines in the ability to bind information together in memory during encoding and retrieve those associations at a later time.
The causes for memory issues and aging is still unclear, even after the many theories have been tested. There has yet to be a distinct link between the two because it is hard to determine exactly how each aspect of aging effects the memory and aging process. However, it is known that the brain shrinks with age due to the expansion of ventricles causing there to be little room in the head. Unfortunately, it is hard to provide a solid link between the shrinking brain and memory loss due to not knowing exactly which area of the brain has shrunk and what the importance of that area truly is in the aging process Attempting to recall information or a situation that has happened can be very difficult since different pieces of information of an event are stored in different areas. During recall of an event, the various pieces of information are pieced back together again and any missing information is filled up by our brains, unconsciously which can account for ourselves receiving and believing false information.
Journal of Brain Research