Building episodic connections: changes in episodic priming with age and dementia

Previous studies of associative encoding that used explicit retrieval tasks have shown both age- and dementia of the Alzheimer type (DAT)-related declines, but such results may be biased by group differences in explicit retrieval. In the present experiment, the authors assessed implicit associative encoding for 25 younger adults (ages 18-25), 73 healthy older adults (ages 59-91), and 65 adults with DAT (ages 59-91) during a speeded word-naming task using an episodic priming measure. Episodic priming refers to the facilitation in responding to a target word after repetition of both words in a prime-target pair, in comparison with simple repetition of the target word with a new prime on each presentation. In contrast with other studies of implicit associative encoding that did not use an implicit episodic priming measure, the present study found both age- and DAT-related declines in associative encoding under conditions of massed learning trials.