Effect of nasal and paranasal cavities on phonation

A possibility that acoustic impression allows evaluation of nasal obstruction was examined. The acoustic impression of nasal obstruction, the nasal flow resistance and the nasal cavity volume were compared with self-evaluation values of obstruction. The coincidence rate of evaluation by acoustic impression is equal to that of the nasal flow resistance. Characters of the humming sound in acoustical analysis do not correlate with the degree of nasal obstruction or the location of nasal obstruction. However acoustic analysis of the humming sound suggests a possibility that nasal obstruction indicator is on the regions below 800 cps and above 3000 cps.