title: Accuracy assessment for AG500, electromagnetic articulograph.
abstract: OBJECTIVE
  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.
  
  
  METHODS
  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.
  
  
  CONCLUSIONS
  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.
authors: Department of Speech and Language Pathology, University of Toronto, Toronto, Ontario, Canada. yana.yunusova@utoronto.ca
authors: Yana
authors: Y
authors: Yunusova
authors: Jordan R
authors: JR
authors: Green
authors: Antje
authors: A
authors: Mefferd
mesh_terms: D001696:Biomechanical Phenomena; D002138:Calibration; D004574:Electromagnetic Fields; D006801:Humans; D007568:Jaw; D009043:Motor Activity; D015203:Reproducibility of Results; D013060:Speech; D013062:Speech Articulation Tests / Q000295:instrumentation*; D014059:Tongue / Q000502:physiology*