When younger adults (left panel) perform attention and memory tests they show brain activation patterns that are balanced between occipital and frontal regions or even have a shift towards greater posterior activation. Dotted and grayed lines indicate impairments. Thus, the effect of aging on the focus of attention may be to blur the boundaries or widen the focus of attention such that older adults have less control over the content of what is currently within the focus of attention (see Figure 1).įigure 1 diagrams a model of age-related changes in cognition based on the model of Cowan 5, 6 and includes patterns of brain activation as measured by fMRI. Older adults may also fail to suppress attention to irrelevant information that has already entered working memory 8. Attentional control impairments imply that older adults allow both relevant and irrelevant information to enter into the focus of attention which will impair performance on any kind of task requiring the ability to differentiate relevant from irrelevant information. In the context of the Cowan 5, 6 information processing model, aging may result in difficulties in controlling the focus of attention. Working memory contains information both inside and outside the focus of attention which has a very restricted capacity, limited in some cases to as little as one item (e.g., 7). In this model, working memory is conceptualized as the activated portion of long-term memory. Model of Information Processing and AgingĬowan 5, 6 proposed a model of information processing that describes the relationships between attention, working memory, and long term memory storage. One way to conceptualize how aging affects cognition is through the model described below. However, older adults also show improvements on cognitive tasks where they can rely on experience to perform well such as tests assessing wisdom and general knowledge 4. Most commonly, healthy older adults show impairments on tasks of attention, working memory, and episodic memory relative to younger adults (i.e., 2– 4. Specifically, studies in healthy older adults show declines in some cognitive domains while showing improvements in others. As there are decreases in biological functions and mental abilities that are normal and happen with the passage of time, it is helpful to understand these changes in order to understand what happens when there is disease in addition to the normal changes. But these diseases do appear in an age-dependent manner and can share some cognitive features with normal aging making it difficult to completely distinguish between signs and symptoms of overt disease and normal aging. Neurological disorders like Alzheimer’s disease (AD) and Parkinson’s disease (PD) are not normal manifestations of aging fated for everyone who lives long enough to have them.
PATHOLOGICAL AGING DEF FREE
Normal aging has been defined as aging changes that occur in individuals free of overt diseases of the nervous system.
The study of cognitive aging seeks to examine how these processes change over time and between people. It is the study of how people perceive, learn, remember, and think about information. The field of cognitive psychology is concerned with discovering the form of mental representation and the processes that access them. This paper describes normal patterns of cognitive change in healthy aging, describes how some of these processes can be explored with functional neuroimaging, and briefly describes the work attempting to describe differences between normal and pathological cognitive aging. Generally, studies show that older adults activate regions of the frontal cortex more than younger adults while younger adults activate more posterior cortical areas.
More recent work in task-related functional neuroimaging has further elucidated the effects of aging on brain circuitry related to these cognitive processes. Many years of research in the psychology of cognitive aging has described patterns of age-related changes in cognitive processes with older adults performing worse than younger adults on tests of attention, working memory and episodic memory and better on tests of general knowledge. Other cognitive domains improve in functioning as aging continues such as wisdom and some kinds of decision making. Cognition has many component processes, some of which are impaired by normal aging like attention and memory as a result of changes in perceptual systems or speed of processing. The idea that our cognitive abilities change with age has support from empirical research as well as from anecdotal reports.
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