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Variability of Electroglottographic Glottal Closed Quotients
Necessity of Standardization to Obtain Normative Values
Romain E. Kania, MD;
Stéphane Hans, MD;
Dana M. Hartl, MD;
Philippe Clement, MD;
Lise Crevier-Buchman, MD;
Daniel F. Brasnu, MD
Arch Otolaryngol Head Neck Surg. 2004;130:349-352.
Objective To demonstrate the variability of electroglottographic measurements of the glottal closed quotient (GCQ) in normal subjects by the calculation method used, fundamental frequency, and intensity.
Design Prospective study.
Setting Tertiary university-based referral center.
Subjects Twenty healthy male volunteers without laryngeal disorder. Three successive sustained productions of the vowel /a/ were performed by each subject. Electroglottographic recordings of GCQ were obtained using the criterion level method, which defines an approximate duration of glottal closure and opening. Glottal closed quotient values were calculated based on criterion levels ranging from 10% to 40%.
Main Outcome Measures The extent of correlation between GCQ variation and the mean fundamental frequency and intensity.
Results As the criterion level increased, a decrease in the mean GCQ was recorded, which was significant with a 10% criterion level increase, up to a critical level of 25%. A significant positive correlation was found between GCQ and the variables of fundamental frequency and intensity.
Conclusions This study demonstrated significant effects of the criterion level used, fundamental frequency, and intensity in the determination of normative values of GCQ. Normative values can only be assessed through the standardization of one criterion level reached by consensus.
From the Voice, Biomaterials, and Head and Neck Oncology Research Laboratory, Department of Otorhinolaryngology–Head and Neck Surgery, Georges Pompidou European Hospital, University of Paris V, and the Phonetics Institute of Paris-Sorbonne, University of Paris III, Centre National de la Recherche Scientifique-Unité Mixte de Recherche 7018, Paris, France. The authors have no relevant financial interest in this article.
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