[Glottal and supraglottal configuration during whispering]

The purpose of the study was to assess glottal and supraglottal configurations during whispering in comparison to habitual phonation and to visually estimate to what extent force is exerted onto the vocal fold epithelium during whispering. Is whispering a good compromise between preservation of epithelium and permission to communicate orally, e. g. postoperatively?

We investigated on 100 patients with organic or non-organic voice disorders. Patients with vocal fold immobility and patients with organic lesions large enough to impede glottal closure were excluded. Videolaryngoscopy and stroboscopy was performed via flexible endoscopy. During fiberoscopy the patients were asked (i) to phonate and then whisper a series of vowels in various loudness levels and (ii) to count to 10 voiced and whispered in various loudness levels. The extent of vocal fold adduction and supraglottal configuration were assessed and whispering compared with voiced phonation.

Interindividual differences in glottal and supraglottal configuration during whispering were seen. The two different and most frequently seen glottal area patterns were determined by the position of the vocal processes - either adducted or abducted. Adduction resulted in sole cartilaginous triangle formation or 'kissing processes', abduction in ligamentous and cartilaginous triangle. Another surprising result was that with increasing loudness either a narrowing or widening of glottal and supraglottal structures was visible.

There are different patterns of glottal and supraglottal configuration during whispering. Although the vocal folds can show partial or total contact over the membranous parts, the lack of additional vibration of the vocal folds suggests that epithelial forces are smaller than with additional vibratory shear stress. Thus, whispering may be considered and allowed for postoperative communication purposes, when patients follow instructions for low-effort whispering.