Message-Encoding Techniques for Augmentative Communication Systems The Recall Performances of Adults With Severe Speech Impairments Research Article
Research Article  |   August 01, 1992
Message-Encoding Techniques for Augmentative Communication Systems
 
Author Affiliations & Notes
  • Janice Light
    Department of Communication Disorders The Pennsylvania State University University Park
  • Peter Lindsay
    Department of Communication Disorders The Pennsylvania State University University Park
Article Information
Speech, Voice & Prosodic Disorders / Augmentative & Alternative Communication / Attention, Memory & Executive Functions / Language / Research Articles
Research Article   |   August 01, 1992
Message-Encoding Techniques for Augmentative Communication Systems
Journal of Speech, Language, and Hearing Research, August 1992, Vol. 35, 853-864. doi:10.1044/jshr.3504.853
History: Received April 25, 1991 , Accepted December 16, 1991
 
Journal of Speech, Language, and Hearing Research, August 1992, Vol. 35, 853-864. doi:10.1044/jshr.3504.853
History: Received April 25, 1991; Accepted December 16, 1991

This study investigated the cognitive and linguistic processing demands of message-encoding techniques used to retrieve prestored messages from computer-based augmentative communication systems. Twelve physically disabled adults with severe speech impairments participated in six counterbalanced experimental conditions, consisting of three encoding techniques (salient letter, letter category, and iconic codes), each in a personalized condition in which subjects selected their own codes and in a nonpersonalized condition in which codes were preselected by a clinician. In each of the experimental conditions, the subjects participated in five learning and testing sessions. During these sessions, the subjects learned the codes for lists of 80 messages, half of which involved concrete referents and half abstract concepts. Results indicated that the subjects were more accurate in recalling the codes to retrieve preprogrammed messages when using the two letter encoding techniques than when using the iconic technique. No reliable differences were found between recall performances with personalized codes and with nonpersonalized ones for any of the three encoding techniques. Code recall improved consistently across the series of learning sessions; there were no significant differences in the rates of learning across the encoding techniques. Subjects were found to be more accurate at recalling the codes to retrieve concrete messages than those to retrieve abstract messages.

Acknowledgments
This research was completed in partial fulfillment of the requirements for the PhD program of the first author at the Ontario Institute for Studies in Education (OISE) at the University of Toronto in Toronto, Canada. The research was supported by a grant from the Easter Seal Research Institute, Toronto, Canada.
The authors gratefully acknowledge the feedback and suggestions provided by David Beukelman (University of Nebraska-Lincoln), and by lain Davidson, Dan Keating, and Linda Siegal (Ontario Institute for Studies in Education). The authors are grateful to the individuals who participated in the study. Finally, the authors also wish to thank the staff of the Augmentative Communication Service at the Hugh MacMillan Rehabilitation Centre in Toronto, of the Technical Resource Centre at Bloorview Children’s Hospital in Toronto, and of Erinoak in Mississauga, Canada, for their support and cooperation.
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