Evaluation of the importance of head and probe stabilisation in acoustic rhinometry

As yet theta is no established procedure to ensure the repeatability of aco ustic rhinometry measurements although anecdotal evidence suggests that ins trument fixation improves repeatability. The aim of this study is to valida te the methodology of acoustic rhinometry and determine whether instrument fixation and head stabilisation is necessary. Foul methods we compared in f ifteen healthy volunteers, after nasal decongestion: A) Patient holding the probe (patient-held), B) Probe fixed in a probe stand (probe-stand), C) Pr obe fixed in stand and head stabilised in head rest (head-rest), D) Examine r holding the probe (examiner-performed. The two minimum cross-sectional ar eas and volume between 0 and 5 cm were recorded. The examiner-performed and probe-stand methods were consistently less variable than the other methods . With examiner-performed method, this was significant (p <0.05) versus hea drest and patient-held methods for both measures of minimum cross-sectional area. For nasal volume the examiner-performed method was significantly (p <0.05) less variable than the head-rest method. In conclusion, examiner-per formed acoustic rhinometry is more repeatable than combined head stabilisat ion and instrument fixation and therefore the use of a head-rest may be unn ecessary. Instrument fixation or examiner performed test is also preferable to allowing the patient to position the probe. The repeatability of the pr obe-stand method was similar to the examiner performed method.