Accuracy Assessment for AG500, Electromagnetic Articulograph Purpose The goal of this article was to evaluate the accuracy and reliability of the AG500 (Carstens Medizinelectronik, Lenglern, Germany), an electromagnetic device developed recently to register articulatory movements in three dimensions. This technology seems to have unprecedented capabilities to provide rich information about time-varying positions of articulators. However, strengths ... Research Note
Research Note  |   April 01, 2009
Accuracy Assessment for AG500, Electromagnetic Articulograph
 
Author Affiliations & Notes
  • Yana Yunusova
    University of Toronto, Canada
  • Jordan R. Green
    University of Nebraska–Lincoln
  • Antje Mefferd
    University of Nebraska–Lincoln
  • Contact author: Yana Yunusova, Department of Speech and Language Pathology, Rehabilitation Sciences Building, University of Toronto, 160-500 University Avenue,Toronto, Ontario M5G 1V7, Canada. E-mail: yana.yunusova@utoronto.ca.
Article Information
Research Issues, Methods & Evidence-Based Practice / Speech / Research Notes
Research Note   |   April 01, 2009
Accuracy Assessment for AG500, Electromagnetic Articulograph
Journal of Speech, Language, and Hearing Research, April 2009, Vol. 52, 547-555. doi:10.1044/1092-4388(2008/07-0218)
History: Received September 14, 2007 , Accepted June 11, 2008
 
Journal of Speech, Language, and Hearing Research, April 2009, Vol. 52, 547-555. doi:10.1044/1092-4388(2008/07-0218)
History: Received September 14, 2007; Accepted June 11, 2008
Web of Science® Times Cited: 55

Purpose The goal of this article was to evaluate the accuracy and reliability of the AG500 (Carstens Medizinelectronik, Lenglern, Germany), an electromagnetic device developed recently to register articulatory movements in three dimensions. This technology seems to have unprecedented capabilities to provide rich information about time-varying positions of articulators. However, strengths and weaknesses of the system need to be better understood before the device is used for speech research.

Method Evaluations of the sensor positions over time were obtained during (a) movements of the calibration device, (b) manual movements of sensors in a cartridge within the recording field of the cube, and (c) various speech tasks.

Results Results showed a median error to be under 0.5 mm across different types of recordings. The maximum error often ranged between 1 and 2 mm. The magnitude of error depended somewhat on the task but largely on the location of the sensors within the recording region of the cube.

Conclusion The performance of the system was judged as adequate for speech movement acquisition, provided that specific steps are taken for minimizing error during recording and for validating the quality of recorded data.

Acknowledgments
This research was supported, in part, by National Institute on Deafness and Other Communication Disorders Grant 5R01DC006463-04 and the Barkley Trust. We thank Cynthia Didion for assistance in data management.
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