In the February edition of the Journal of Clinical Sleep Medicine is a study where researchers assessed the ability of non-invasive nasal resistance measurement while awake to predict the amount of upper airway resistance while asleep and on CPAP.
The researchers measured nasal airflow resistance with two different non-invasive techniques. There was no correlation between the two techniques while the subjects were sitting up awake. There was weak correlation between the two techniques while the patietns were awake but lying down on their back.
There was no clear relationship between OSA severity and either subjective reports or objective measurements of nasal airflow resistance while subjects were awake. Airlow resistance in the throat made while subjects slept did not correlate with objective measurements of nasal airflow resistance while awake.
It would be nice to have an objective, non-invasive indicator of throat resistance and/or OSA severity that could be done while the patient is awake in the sleep clinic. Unfortunately, the results from this study do not support measuring nasal airflow resistance for these purposes.