Common Methodological Failures During Videostroboscopic Examinations And The Manipulations

Objective:Videostroboscopy is wildly being used in ENT practice as a perceptual tool for voice evaluation, because of its capacity to record vocal cord oscillation. A few studies used this device to analyze the voice of post-op patients with laryngeal tumor. However, as these patients always complain of severe hoarseness, therefore no effective signal input to stroboscope, there is rare pre-op stroboscopic record being obtained as a control. Thus the aim of this article is to summarize the common methodological failures during procedures of videostroboscopic examination and the ways to handle these problems. The article also introduces a new method to help the strobe to track such aperiodic voice.Method:31 cases with severe laryngeal mass are retrospect studied. To the methodological failures, including gagging, ventricular contrast and no frequency tracking, corresponding handlings and the effects are summarized. EGG sampling under the condition of hard attack is compared with microphone sampling and EGG sampling to conclude which is best method to drive the device track the aperiodic voice.Results:During the first round examination, only 4 out of clcases get the ideal results. Proportion of the patients failing to the procedure is 45.2%because of intolerance, 19.4%because of obstruction from ventricular contraction and 22.6%because of no frequency tracking. Topic anesthesia and phonation guidance could eliminate the effect of the first two factors with the values decreasing to 9.7%and 16.1%.9 patients succeed to get the results, while still 45.2%of patients fail because of no strobe tracking. Finally, after taking the method of EGG sampling with the help of hard attack, the proportion who succeed raise to 51.6%. To the 23 out of 31 patients who could expose the vocal cord and tolerate the procedure, three methods to track frequency, including microphone sampling, EGG sampling and EGG sampling under the condition of hard attack, are used. The latter method markedly increases the probability to track the aperiodic signals.Conclusion:Also gagging, ventricular contract and no frequency tracking are the common methodological failures impede the procedure of videostroboscopic examination, corresponding handlings, to a certain extant, could minimize their effects. EGG sampling under the condition of hard attack is a simple method to help the strobe to track sound frequency.