Magnetometer and X-ray Microbeam Comparison

This article concerns replicability of past results and consistency in data collection using X-ray microbeam and magnetometry, two prominent instruments for speech movement tracking. The same speaker was recorded on both instruments reading identical stimuli and using parallel experimental procedures and the same physician for transducer placement. Data from two X-ray microbeam (XRMB) runs were collected on the same day (transducers re-placed for the second run); 27 months later the analogous data were collected with the Electromagnetic Midsagittal Articulometer (EMMA) system. Vertical movement of the lower lip, tongue tip, and tongue body was analyzed. Extremum positions and peak velocities were identified, and movement displacements and durations calculated. The correlation of these measures between the EMMA and XRMB sessions is very high, almost as high as that between the two XRMB sessions. Subsequent ANOVA confirm that the results obtained using EMMA do not differ substantially from those using X-ray microbeam.