What do we mean by word-finding problems?
Here are some examples:
- increasing use of circumlocutions rather than specific terms (e.g., "I wonder where the thing that goes here is")
- use of empty phrases, indefinite terms, and pronouns without antecedents (i.e., referring to something or someone as "it" or "him / her" without first identifying them by name)
- increased frequency of pauses
These problems are all characteristic of Alzheimer's, but also, to a much lesser extent, of normal aging.
Verbal fluency declines with age
Verbal fluency is measured by how many words fitting a specific criteria you can generate in a fixed time (for example, how many types of fruit you can list in a minute).
Verbal fluency often (but not always) declines as we age. This may be partly because older adults are slower to access information.
Tip-of-the-tongue experiences increase with age
There is no evidence that normal older adults actually lose the meanings of words they know.
Older adults do however have more word-finding problems than younger adults. In particular, as we get older we tend to experience more experiences when the word we are searching for is "on the tip of my tongue" . (For more detail about this, see the research report at Burke 1991)
Picture-naming errors also increase, though not perhaps until the eighties .
Some studies have found a decline in older adults’ ability to produce words when given their definitions, but others haven’t. This may relate to strategy differences.
No structural changes to memory in normal aging
So, older adults do show some of the same type of word-finding problems as Alzheimers patients do, but to a considerably smaller degree. There is little evidence however that this decline is due to any structural changes in semantic memory with age. Normal younger and older adults give the same sort of responses. (Alzheimers patients on the other hand, become more eccentric in their word associations).
Older adults may tend to use different memory strategies than younger adults
While older adults are slower to make category judgments (e.g., "Is a tomato a fruit? True or false"), they do not give responses different from those of younger adults, supporting the view that semantic organization hasn't changed. However, there is some evidence that young and old differ in the way they judge similarity (older adults seem to rely more on distinctive features; younger adults use both common and distinctive features). This may however be due to strategy differences.
There is no evidence for any decline in prose comprehension with age. However, when there is a large load on memory (when the text is complex, for example), older adults find retrieving general knowledge more difficult.
It appears that encoding of new information might become less context-specific with age, but this may only relate to particular types of context information. It might only be that older adults are less inclined to attend to such (largely irrelevant) details as: whether something was printed in upper or lower case; the sex of a speaker; the color in which a word is printed. The temporal and spatial contexts are also likely to be less important. In other words, older adults seem to encode less information about the source of new information (the circumstances in which the information was acquired) than younger adults.