Effects of level of processing at encoding and types of retrieval task in mild cognitive impairment and normal aging

Abstract

A total of 16 young (M = 27.25 years), 13 healthy elderly (M = 75.38 years), and 10 older adults with probable mild cognitive impairment (MCI; M = 78.6 years) carried out a task under two different encoding conditions (shallow vs. semantic) and two retrieval conditions (free recall vs. recognition). For the shallow condition, participants had to decide whether the first or last letter of each word in a list was “E.” For the semantic condition, they had to decide whether each word represented a concrete or abstract entity. The MCI group was only able to benefit from semantic encoding to the same extent as the healthy older adults in the recognition task, whereas the younger and healthy older adults benefited in both retrieval tasks. These results suggest that the MCI group required cognitive support at retrieval to make effective use of semantic processing carried out at encoding. In the discussion, we suggest that adults with MCI engage more in deep processing, using the semantic network, than hitherto thought.

Keywords:

• Episodic memory
• Level of processing
• Retrieval task
• Normal aging
• Mild cognitive impairment

This study was supported by grants from the Groupe d'Intérêt Scientifique Institut de la Longévité et du Vieillissement (2004). The authors thank Sylvie Belleville for her helpful comments and suggestions during the writing of this paper, Badiâa Bouazzaoui for her help in the conception of the experimental protocol, and Elizabeth Yates for reviewing the use of English language style in this article.