Memory and word learning in students with primary developmental language learning impairments (LI)

Professor Karla McGregor (University of Iowa)

Summary

People with primary developmental language learning impairments (LI) have small and shallow vocabularies; consequently, they are disadvantaged academically and professionally. Our long-term goal is to develop a full explanation of this problem. Our current objective is to examine the memory processes that support word learning in this population.

We are focusing recruitment efforts on post-secondary students with LI. Our motivations are three-fold: Vocabulary problems associated with LI persist, and by some reports increase, from preschool to adolescence; Students with LI are a growing segment of the college/university population in the U.S.; the stakes are high for these citizens who, having been accepted for post-secondary studies despite their disabilities, have a great opportunity to contribute to society but who, without adequate support, are at a high risk for failure to matriculate.

In a series of training studies, we are examining three memory processes that support word learning and retention: encoding, consolidation, and retrieval. Encoding, the experience (exposure)-dependent process via which a new memory is formed, is followed by consolidation, a slower process via which the fragile new memory is stabilized, enhanced and integrated into a network of related memories. Unlike encoding, consolidation does not depend upon overt experience with the word and referent. Subsequent retrieval can further strengthen the memory trace and can set in motion the processes of re-encoding and re-consolidation. Our central hypothesis is that the word learning problems that characterize LI are a consequence of deficits in experience-dependent memory processes. Encoding rather than consolidation is the bottle-neck. Therefore, our primary aim is to determine the integrity of experience-dependent and -independent memory processes of learners with LI. Additionally, we aim to identify experiences that promote optimal encoding among learners with LI and to describe the complex interactions between retrieval, (re)encoding, and (re)consolidation that culminate in poorer or stronger retention among learners with LI.

Key Publications

McGregor KK, Licandro U, Arenas R, Eden N, Stiles D, Bean A, Walker E. Why Words

are Hard for Adults with Developmental Language Impairments. J Speech Lang Hear

Res. 2013 Sep 10;PubMed PMID: 24023376; NIHMSID: 530324.

Further Information

Contact: Karla McGregor (karla-mcgregor@uiowa.edu)

Keywords: developmental language impairment, word learning, memory, vocabulary