Application of the HRES 5562 Camera Using the HSDI Technique in the Diagnosis of Glottal Insufficiencies in Teachers

Abstract

Teachers are the largest group of professional voice users with predispositions to functional or organic changes in the larynx. The dysfunction of intrinsic muscles of the larynx frequently occurs which leads to changes in parameters of quality of voice (dysphonia). The aim of the study is the assessment of parameters of vocal folds vibrations, Mucosal Wave morphology, Glottal Closure Type and Open Quotient (OQ) using High Speed (HS) camera and High Speed Digital Imaging (HSDI) technique in teachers with disorders of voice quality classified in GRBAS scale in glottal insufficiencies. The study included group of 50 teachers of both genders, working in primary and secondary education units for 15 years, without systemic diseases with disorders of quality of voice confirmed by the results in GRBAS scale assessment. Vocal folds vibrations were assessed with HS camera by R. Wolf and HSDI technique. Rigid endoscope with 90o optics by the same company was used in the study. Vocal folds vibrations were registered with the speed of 4000 frames/sec. Regularity, symmetry of vibrations, Mucosal Wave (MW) morphology as well as Glottal Closure Type were assessed. Numerical value of OQ was determined in anterior, middle and posterior segment of the glottis during phonation. Assessment of real vibrations of vocal folds revealed irregularity, mean asymmetry of vibrations, MW reduction as well as glottal insufficiency, the most frequently (96%), in the middle segment - type E according to European Laryngological Society, less frequently (4%) - type E+C. The highest value of OQ (average 0.98) was registered in the middle segment of the glottis. In GRBAS scale, significant dysphonia has been registered, classified as G3R3B3A3 without the features of voice strain - S0. In group of teachers with extensive professional experience, glottal insufficiency in the middle segment was registered the most frequently which was confirmed by high values of OQ in this region obtained with HSDI technique. What is more, irregularity, mean asymmetry and asynchrony of vibrations with MW reduction were registered which confirmed the existence of glottal insufficiency in this group. GRBAS scale was useful in preliminary evaluation of dysphonia and its severity, however, the diagnosis of its clinical form was possible only with visualization of the larynx and objective parameters obtained with HSDI.