Correlation of glottal closure using concurrent ultrasonography and nasolaryngoscopy in children: a novel approach to evaluate glottal status.

OBJECTIVES

Endoscopic procedures to assess aerodigestive symptoms by evaluating glottal motion are not practical in neonates because of small nares, respiratory difficulties, or additional stress. Our objective was to determine the temporal correlation between concurrent nasolaryngoscopy (NLS) and ultrasonography (USG) evaluation of glottal motion.

METHODS

Simultaneous USG of the glottis was performed in 10 subjects (5 males, 5 females, age = 4.5 months to 7.1 years) that underwent diagnostic flexible outpatient NLS. The USG transducer was placed on the anterior neck at the level of the vocal cords. The video signals from NLS and USG were integrated and synchronized into real-time cine loops of 1-min duration.

RESULTS

Frame-by-frame evaluation of 10,800 frames identifying glottal opening and closure time was compared between the two modalities by three observers and the timing of glottal closure was marked. Two investigators, blinded to NLS images, identified ultrasonographically determined glottal closure with 99% and 100% accuracy, and the mean probability of missing a closure frame was 0.007 (95% CI = 0.0008-0.024).

CONCLUSIONS

Temporal characteristics of glottal motion can be quantified by USG with perfect reliability and safety. This method can be useful in measuring the presence and the duration of laryngeal adduction.