[Experimental study on the resonance of the paranasal sinus]

Contribution of paranasal sinuses to the acoustic properties of the nasal tract

BACKGROUND

The contribution of the nasal and paranasal cavities to the vocal tract resonator properties is unclear. Here we investigate these resonance phenomena of the sinonasal tract in isolation in a cadaver and compare the results with those gained in a simplified brass tube model.

METHODS

The resonance characteristics were measured as the response to sine sweep excitation from an earphone. In the brass model the earphone was placed at the closed end and in the cadaver in the epipharynx. The response was picked up by a microphone placed at the open end of the model and at the nostrils, respectively. A shunting cavity with varied volumes was connected to the model and the effects on the response curve were determined. In the cadaver, different conditions with blocked and unblocked middle meatus and sphenoidal ostium were tested. Additionally, infundibulotomy was performed allowing direct access to and selective occlusion of the maxillary ostium.

RESULTS

In both the brass model and the cadaver, a baseline condition with no cavities included produced response curves with clear resonance peaks separated by valleys. Marked dips occurred when shunting cavities were attached to the model. The frequencies of these dips decreased with increasing shunting volume. In the cadaver, a marked dip was observed after removing the unilateral occlusion of the middle meatus and the sphenoidal ostium. Another marked dip was detected at low frequency after removal of the occlusion of the maxillary ostium following infundibulotomy.

CONCLUSION

Combining measurements on a simplified nasal model with measurements in a cadaveric sinonasal tract seems a promising method for shedding light on the acoustic properties of the nasal resonator.

An acoustical analysis of the effects of maxillary sinus augmentation on voice quality

OBJECTIVE

Increased experience in sinus lifting procedures has led to a number of literature reports, but the potential effects of sinus lifting on voice quality is not clearly addressed in clinical studies. The aim of this study was to objectively investigate the effects of sinus lifting on alterations in voice quality and, in particular, on vocal resonance.

STUDY DESIGN

A total of 17 patients who were in need of bilateral sinus augmentation were recruited. Acoustic analyses were performed before and after surgery. Volume changes in the sinuses were recorded before and after surgery using dental volumetric tomography. The Friedman test with Bonferroni correction was used to analyze the data.

RESULTS

Changes in the perturbation parameters of acoustic sound analysis were found to be statistically significant.

CONCLUSIONS

We recommend that all patients (especially voice professionals) be informed about the possible effects of sinus lifts on speech and voice alterations.

Effects of sinus lifting on voice quality. A prospective study and risk assessment

A variety of potential complications associated with sinus lift surgery have been reported in the literature. However, potential alterations of voice quality following sinus elevation have so far not been mentioned or evaluated scientifically. For the majority of patients, slight changes of the voice pattern are of no importance. However, for voice professionals, whose voices have become part of their distinctive profession or trademark, minimal changes may have dramatic consequences. This specific group of patients, such as speakers, actors and singers, depend on the particular quality and timbre of their voice for their livelihood. Consequently, the purpose of this study was to assess the effects of sinus lifting on voice quality in the above patient group. In a collaborative interdisciplinary effort, the Departments of Oral Surgery and Otorhinolaryngology, Section of Phoniatrics and Logopedics, thoroughly evaluated a series of voice parameters of four patients undergoing sinus lifting pre- and postoperatively. The parameters analyzed included pitch, dynamic range, sound pressure level, percent jitter, percent shimmer and noise-to-harmonics ratio with special emphasis on formant analysis. No changes were detected in any of the commonly evaluated parameters. These were rated subjectively by patients and their friends or relatives and objectively with instrumental tools under isolated phoniatric lab conditions. In conclusion, sinus lift surgery appears to be a safe, predictable evidence-based method for regenerating the highly atrophic posterior maxilla, which does not jeopardize the individual characteristic voice pattern of high-profile patients critically dependent on their voices for their livelihood.