Non-metallic ultrasound probe holder for co-collection and co-registration with EMA

Co-collection and co-registration of ultrasound images of the tongue and articulometry data requires the stabilization of the ultrasound probe relative to the head using a non-metallic system. Audio, ultrasound, and articulometry data were recorded from 11 North American English speakers reading 10 blocks of 25 sentences, speaking for 2 minutes at a time, spanning a recording time of 45 minutes. The 95% confidence interval for ultrasound probe roll relative to head motion was 1.35◦, and 2.12 mm for lateral displacement, such that ultrasound probe displacement is within acceptable rotational and translational parameters as described in the HOCUS paper [9]. The proper use of this probe holder could also allow for adequate ultrasound probe stabilization without external marker tracking for post-processing correction, making this probe holder suitable for field research.