Odiosoft- Rhino; Nasal sound & Nasal airflow analysis
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The computerized analysis of the nasal sound reflects the nasal airflow. Odiosoft-rhino is a new software program that analyses the nasal sound in order to use in the research area and clinical applications. Odiosoft-rhino aim to analyze automatically the spectral parameters of the nasal sound in healthy people by our new versatile PC-based nasal sound analyzer software.
Nasal sound analyses
The Biomechanics of nasal resistance relate to the study of turbulent flow. Resistance is pressure divided by flow. Based on laminar flow equations, decreases in r, or the nasal airway radius, cause 4-fold decreases in flow, or Q (where L is length, r is radius, P is pressure, is viscosity, and r is density) . Mathematically, a Reynolds number (Re) greater than 2000 is equated with turbulent flow. (1)
Turbulent flow generates louder sound waves (2). Sound wave spectra are clearly linked to respiratory airflow rate. Sound increases with the air flow, engendering a marked upward shift in frequencies in the spectra. 9 Other recent studies revealed that flow modifies both the intensity and the frequency distribution in the spectrum. (4,5,6) The relationship between flow and sound depends on many factors, including upper-airways configuration and, especially, the subject themselves. However, for every subject, the mean amplitude and the mean frequency are increasing functions of the flow.
Effect of Nasal Septal Deviation on Nasal Airflow Pattern
Nasal septal deviation makes narrowing in nasal cavity and decrease cross-sectional area of it. This condition makes increase in velocity of nasal airflow and transforms it from a laminar pattern to a more turbulent pattern. Turbulent flow produces nasal sound waves. Nasal sound frequency and intensity increases with the turbulent air flow, engendering a marked shift upward in frequencies in the spectra. The nasal sound intensity at high frequency increases proportionally related to the degree of the patients with nasal septal deviation.
Effect of nasal valve area on inspirator nasal sound spectra
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.
References
1) Kerr A, ed: Rhinology. In: Scott-Brown's Otolaryngology. 6th ed. Oxford: Butterworth Heinemann; 1997.
2) Moin P, Bewley T. Feedback control of turbulence. Applied Mechanics Reviews 47: 3-13, 1994.
3) Charbonneau G, Sudraud M, Soufflet G. Method for the evaluation of flow rate from pulmonary sounds. Bull Eur Physiopathol Respir 23:265-270,1987.
4) Kraman SS, Pasterkamp H, Kompis M, Takase M, Wodicka GR. Effects of breathing pathways on tracheal sound spectral features. Respir Physiol 111: 295-300,1998.
5) Kiyokawa H, Greenberg M, Shirota K, Pasterkamp H. Auditory detection of simulated crackles in breath sounds. Chest 119:1886-1892, 2001.
6) Homs-Corbera A, Fiz JA, Morera J, Jane R. Time-frequency detection and analysis of wheezes during forced exhalation. IEEE Trans Biomed Eng 51:182-6, 2004.
