Comparison of nasal sound spectral analysis and peak nasal inspiratory flow before and after decongestion in patients with nasal obstruction

Objectives: We compared the results of nasal sound spectral analysis (NSSA) with the results of peak nasal inspiratory flow (PNIF) testing and use of a visual analog scale in patients with allergic rhinitis with nasal obstruction. Methods: We performed NSSA and PNIF testing on 38 patients with allergic rhinitis and 35 healthy subjects. A diagnostic decongestion test was performed on the patients (not on the control subjects). Twenty minutes after decongestant was sprayed into the nostrils, NSSA and PNIF testing were performed again. Results: There was a significant difference in the PNIF values and the nasal inspiratory sound intensities before and after decongestion (p < 0.001). There was a correlation between the NSSA results at the frequency range of 2 to 4 kHz and the PNIF results. The calculated cutoffs between normal and pathological values were 14.8 dB (2 to 4 kHz) for NSSA and 116 ± 14.1 L/min for PNIF testing. No significant differences were computed between NSSA and PNIF testing in terms of sensitivity (0.71 versus 0.76) or specificity (0.74 versus 0.80). Conclusions: Use of NSSA and PNIF testing together for assessment of nasal obstruction in allergic rhinitis provides clinical relevance in that it allows a fair degree of reliability. Such testing can be performed as a surrogate for rhinomanometry.