Encoding Deficits Impede Word Learning and Memory in Adults With Developmental Language Disorders Purpose The aim of this study was to determine whether the word-learning challenges associated with developmental language disorder (DLD) result from encoding or retention deficits. Method In Study 1, 59 postsecondary students with DLD and 60 with normal development (ND) took the California Verbal Learning Test–Second Edition, Adult ... Research Article
Research Article  |   October 17, 2017
Encoding Deficits Impede Word Learning and Memory in Adults With Developmental Language Disorders
 
Author Affiliations & Notes
  • Karla K. McGregor
    The University of Iowa, Iowa City
  • Katherine Gordon
    The University of Iowa, Iowa City
  • Nichole Eden
    The University of Iowa, Iowa City
  • Tim Arbisi-Kelm
    The University of Iowa, Iowa City
  • Jacob Oleson
    The University of Iowa, Iowa City
  • Disclosure: The authors have declared that no competing interests existed at the time of publication.
    Disclosure: The authors have declared that no competing interests existed at the time of publication. ×
  • Correspondence to Karla K. McGregor: karla-mcgregor@uiowa.edu
  • Editor-in-Chief: Sean Redmond
    Editor-in-Chief: Sean Redmond×
  • Editor: Lisa Archibald
    Editor: Lisa Archibald×
Article Information
Development / Language Disorders / Attention, Memory & Executive Functions / Language / Research Articles
Research Article   |   October 17, 2017
Encoding Deficits Impede Word Learning and Memory in Adults With Developmental Language Disorders
Journal of Speech, Language, and Hearing Research, October 2017, Vol. 60, 2891-2905. doi:10.1044/2017_JSLHR-L-17-0031
History: Received January 23, 2017 , Revised May 26, 2017 , Accepted June 5, 2017
 
Journal of Speech, Language, and Hearing Research, October 2017, Vol. 60, 2891-2905. doi:10.1044/2017_JSLHR-L-17-0031
History: Received January 23, 2017; Revised May 26, 2017; Accepted June 5, 2017

Purpose The aim of this study was to determine whether the word-learning challenges associated with developmental language disorder (DLD) result from encoding or retention deficits.

Method In Study 1, 59 postsecondary students with DLD and 60 with normal development (ND) took the California Verbal Learning Test–Second Edition, Adult Version (Delis, Kramer, Kaplan, & Ober, 2000). In Study 2, 23 postsecondary students with DLD and 24 with ND attempted to learn 9 novel words in each of 3 training conditions: uncued test, cued test, and no test (passive study). Retention was measured 1 day and 1 week later.

Results By the end of training, students with DLD had encoded fewer familiar words (Study 1) and fewer novel words (Study 2) than their ND peers as evinced by word recall. They also demonstrated poorer encoding as evinced by slower growth in recall from Trials 1 to 2 (Studies 1 and 2), less semantic clustering of recalled words, and poorer recognition (Study 1). The DLD and ND groups were similar in the relative amount of information they could recall after retention periods of 5 and 20 min (Study 1). After a 1-day retention period, the DLD group recalled less information that had been encoded via passive study, but they performed as well as their ND peers when recalling information that had been encoded via tests (Study 2). Compared to passive study, encoding via tests also resulted in more robust lexical engagement after a 1-week retention for DLD and ND groups.

Conclusions Encoding, not retention, is the problematic stage of word learning for adults with DLD. Self-testing with feedback lessens the deficit.

Supplemental Materials https://doi.org/10.23641/asha.5435200

Acknowledgment
This work was supported by the National Institutes of Health (5R01DC011742), awarded to Karla McGregor, principal investigator.
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