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Computer based analysis of nasal airflow: A new technique

Healthy adults breathes quietly at rest, the nasal airways provide half the airflow resistance of the entire system of respiratory air passages. Dimensions and shape of the airway lumen and airflow velocity together determine the magnitude of resistance to airflow. We analyzed and compared the sound of the nasal airflow at the healthy adults in the nasal valve, inferior meatus and middle meatus. The analyses include time expanded waveform, spectral analysis with time averaged fast Fourier transform, automatic detection and waveform analysis of nasal sound. Frequency values in nasal valve and inferior meatus were obviously higher than the values in middle meatus. We stated that intensity of nasal sound is related with geometric considerations of nasal cavities and nasal airflow velocity. The method can be a new technique for evaluation of nasal airflow.

Frequency Spectra of Normal Expiratory Nasal Sound

Background: The computerized analysis of the nasal sound reflects the nasal airflow. We have developed a new software program that analyzes the nasal sound to use in the research area and clinical applications. We aimed to analyze automatically the spectral parameters of nasal sound in healthy people by our new versatile PC-based nasal sound analyzer software.

Methods: In this study, we analyzed and recorded the expiratory nasal sound in 30 healthy people. This analysis includes the time-expanded waveform, the spectral analysis with time-averaged fast Fourier transform, the automatic detection, and the waveform analysis of nasal sound.

Results: We calculated the mean frequency of low-intensity sound (LIS) and high-intensity sound (HIS). The mean frequency of LIS was found as 1254 ± 10.23 Hz at the right nose and 1375 ± 18.45 Hz at the left nose. The mean frequency of HIS was found as 2453 ± 22.23 Hz at the right nose and as 2234 ± 21.12 Hz at the left nose. These results showed that the values between LIS and HIS are statistically significant (p < 0.005) and different from each other. We found that the nasal sound of the similar nasal airflow was the same type and amplitude in the analysis of the nasal sound recordings.

Conclusion: The frequency of the nasal sound is an indicator of the intensity of the nasal airflow. The method that provides the analysis of the nasal sound may lead to a new diagnostic method. The method, which is noninvasive, rapid, of low cost, and even applicable for small children, requires little cooperation of the subjects. In addition, it will be possible to record and save the analysis of the nasal airflow as digital data.

Effect of nasal valve area on inspirator nasal sound spectra

Objectives: Nasal valve area is the narrowest segment of the nasal airway and effect nasal airflow transforming it from laminar pattern to a more turbulent pattern. Turbulent flow generates louder nasal sound waves. We have researched the effects of nasal valve area on the inspiratory nasal sound spectra in this study.

Study Design: Prospective study

Methods: In this study, we have spectral analyzed and recorded the inspiratory nasal sound in 22 healthy people with and without "Cottle maneuver". This analysis includes the time averaged Fast Fourier Transform. We have analyzed the sound frequency and intensity.

Results: We have found an increase in sound intensity at high frequency in the sound analyses of the patients without the "Cottle maneuver"; whereas, a decrease in sound intensity at high frequency was found in patients with the "Cottle maneuver".

Conclusion: The nasal valve area plays an important role in the transformation of the nasal airflow from a laminar pattern to a more turbulent pattern. This condition affects nasal sound spectra and produces a marked shift upward in frequencies in the spectra. I think that this method may be a new way of evaluating the nasal valve area.