An assessment of the reproducibility of combined glottography in a clinical setting.

Although combined glottography has potential as a clinical tool, it has had limited use in the monitoring of laryngeal function before and after treatment. There is no data about the standardization nor reproducibility of the procedure. An indication of the reproducibility of combined glottography is paramount if changes in laryngeal function are to be measured accurately. Using a standardized technique, two complimentary studies examined the reproducibility of combined glottography within one sitting (Study 1) and over time (Study 2). The components of variance were analysed (ANOVA). In Study 1 the variance under controlled conditions for Open Quotient (OQ) and Speed Quotient (SQ) was only 13% and 18% respectively of the total, whilst in Study 2 the variance over time for OQ and SQ was 55% and 58% respectively. Under controlled conditions combined glottography is a reproducible technique.