<P> 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 1% to 25% per year; in one study 24% of MCI patients progressed to AD in 2 years and 20% more over 3 years, whereas another study indicated that the progression of MCI subjects was 55% in 4.5 years . Some patients with MCI, however, never progress to AD . </P> <P> 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 . </P> <P> 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 . </P> <P> 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 . </P>

Which type of memory shows a much greater decline with age than others