Testing the Generalized Slowing Hypothesis in Specific Language Impairment This study investigated the proposition that children with specific language impairment (SLI) show a generalized slowing of response time (RT) across tasks compared to chronological-age (CA) peers. Three different theoretical models consistent with the hypothesis of generalized slowing—a proportional, linear, and nonlinear model—were examined using regression analyses of group RT ... Research Article
Research Article  |   October 01, 1999
Testing the Generalized Slowing Hypothesis in Specific Language Impairment
 
Author Affiliations & Notes
  • Jennifer Windsor
    University of Minnesota Minneapolis
  • Mina Hwang
    University of Minnesota Minneapolis
  • Corresponding author: e-mail: windsor@umn.edu
Article Information
Language Disorders / Specific Language Impairment / Language / Research Articles
Research Article   |   October 01, 1999
Testing the Generalized Slowing Hypothesis in Specific Language Impairment
Journal of Speech, Language, and Hearing Research, October 1999, Vol. 42, 1205-1218. doi:10.1044/jslhr.4205.1205
History: Received September 21, 1998 , Accepted March 10, 1999
 
Journal of Speech, Language, and Hearing Research, October 1999, Vol. 42, 1205-1218. doi:10.1044/jslhr.4205.1205
History: Received September 21, 1998; Accepted March 10, 1999

This study investigated the proposition that children with specific language impairment (SLI) show a generalized slowing of response time (RT) across tasks compared to chronological-age (CA) peers. Three different theoretical models consistent with the hypothesis of generalized slowing—a proportional, linear, and nonlinear model—were examined using regression analyses of group RT data. Each model was an excellent fit with the RT data. The most parsimonious model indicated that the SLI group was proportionally slower than the CA group. Mean RTs of the SLI group were about one fifth slower across tasks than the CA group's mean RTs. Less slowing was evident for a subgroup of young children with expressive SLI than for children with mixed (expressive and receptive) SLI. Although the mean RT data reflected many individual SLI children's RT performance, not all SLI children showed generalized slowing.

Acknowledgments
This research was supported by a grant to the first author from the National Institute on Deafness and Other Communication Disorders (R29-DC02402). Valuable comments on an earlier version of the manuscript by Jan Edwards, two anonymous reviewers, Nancy Brady, and Joe Reichle are greatly appreciated.
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