Value of acoustic rhinometry in environmental medicine

It is a weak point of environmental medicine that health disturbances, e.g. functional affections of the upper respiratory tract, cannot be objectivel y judged by physicians resp. researchers. In this study, the validity of ac oustic rhinometry, a method giving information on cross-sectional areas of the upper airways by means of ultrasound probing, was tested in 40 voluntee rs seven times during one year. Furthermore, using a simplified model of th e nose the accuracy of this method to measure the minimal cross-sectional a rea (MCA) in the nose was tested. The measurements were extremely confounde d by the mode of connection to the nose (e.g. selected adapter, direction o f application) and by the MCA in the nasal cavity. Statistical analyses sho wed a good reproducibility of measurements repeated within minutes, but sug gested an intrapersonal variability over the analyzed examination phases du e to apparatus independent factors. However, this variability could not be explained by influencing and confounding factors obtained by questionnaire, medical history, and physical examination. The test model showed little to great errors (1.5 to 568.5 %) between the actual and the measured MCA, dep ending on the diameter. It is concluded that the method of acoustic rhinome try has to be standardized before it's value for environmental medicine can finally be judged. Further studies are necessary that should focus among o thers on factors influencing the variability of MCA and the effect of MCA o n the measurement of the area behind the MCA. So far, the use of acoustic r hinometry for the evaluation of nasal function cannot be recommended.