The Vox-EMA (electromagnetic articulography) tracking system captures dynamic orofacial and articulatory movements. This information can be used for research in the rehabilitation of speech pathologies. Microsensors attached to the tongue, lips, jaw and face record 5DOF (five degrees of freedom) movements without line-of-sight occlusions. Up to 16 5DOF sensors can be used at once to produce a detailed model of transpired motion.
Minimal latency and noise, combined with high temporal and spatial accuracy, ensure the fastest and most subtle of movements are recorded the instant they occur. When used with a microphone, the Vox-EMA will synchronize audio with kinematic measurements, providing researchers with rich data to correlate voice production to articulatory movement.
With its intelligent hardware design, seamless audio synchronization, and intuitive software, the Vox-EMA puts the focus on fast, accurate data collection – not lengthy setup or post-processing.
The Vox-EMA provides a highly configurable, flexible measurement method for managing the unique data collection parameters of your experiment or clinical application. The biggest challenge of any speech study is not being able to see what’s happening inside the mouth. Using attached sensors, digitized 3D points and palate traces, the Vox-EMA reports and displays 3D measurements in the Vox-VRI software, providing visibility into previously unviewable articulatory movements.
What’s more, you can see these movements in real-time for immediate subject assessment. You can also automatically save a recording of the transpired movements (measurements) for a comprehensive analysis of research in the following areas:
The Vox-EMA tracks extremely fast and subtle movements with sub-millimetre accuracy and repeatability: sensors are tracked to a static positional accuracy up to 0.9 mm RMS; 6DOF reference disc up to 0.6 mm RMS.
Accuracy remains consistent when tracking at 100 Hz, 200 Hz or 400 Hz. Even if the subject moves, or if the sensors are out of sight, accurate tracking is continuously maintained.
The Vox-EMA system components, measurement volume, and sensors are factory (pre-) calibrated. There’s no need to manually calibrate the system prior to data collection. The accuracy and repeatability of 3D positions are validated using a coordinate measurement machine (CMM) within our calibration facility to ensure reliable measurement performance, for credible measurement results.
|5DOF Sensor||Dome Volume (RMS)|
|• Position||• 0.9 mm|
|• Orientation||• 0.2°|
|6DOF Sensor||Dome Volume (RMS)|
|• Position||• 0.6 mm|
|• Orientation||• 0.3°|
|Number of Sensors Tracked Simultaneously||Up to 16 5DOF; up to 8 6DOF|
|Sample Frequency (Configurable)||100 Hz, 200 Hz, 400 Hz|
|Measurement Volume||Dome (660 mm Ø x 960 mm Ø)|
|HARDWARE DIMENSIONS (HxWxD)|
|Field Generator||200 mm x 200 mm x 70 mm|
• Optotrak Certus® from NDI*
• Included with sample MATLAB® application code
Some measurement methods are true but not precise; others are precise, but not true. The Vox-EMA provides discrete 3D measurements that are both true and precise, without the use of filtering, averaging or other black-box processing techniques.