Nasality Evolution in a Nasal Polyposis Context: Multiparametric Evaluation: Articulatory (Imaging), Aerodynamics, Acoustics and Perception

"Nasal polyposis, a pathology related to speech Nasal polyposis (NP) is a chronic bilateral inflammation of the sinonasal mucosa characterized by the development of polyps in the sinus and nasal cavities. In the general population, its prevalence is 4% with a clear increase from the age of 50 years. Two clinical forms of NP exist: primary polyposis which is isolated or integrated in Widal's disease, secondary polyposis when it appears in the context of diseases such as cystic fibrosis, ciliary dyskinesia or immune deficiencies. NP is a diffuse rhinosinusitis, i.e. it affects both the anterior and posterior sinuses bilaterally. When drug treatment is not effective, and the patient's quality of life is impaired, surgery is proposed.

Surgical treatment consists of removing the polypoid mucosa to repermeabilize the nasal cavities and/or to enlarge the ostia (communication openings between the nasal cavities and the sinuses) and to allow drainage again. This surgery goes beyond the repermeation of the sinuses since it will allow to widen the nasal cavity with aerodynamic and acoustic consequences on speech; indeed, it will allow to bring a greater resonance of the vocal and nasal duct. To our knowledge, there are few studies that have focused on the impact of NP and its treatment on speech. Yet there is a real demand from patients to obtain answers related to the impact of this surgery on their voice. A pathology such as NP falls directly within the scope of clinical phonetics, i.e. the description and understanding of the mechanisms of articulatory and acoustic production of speech, applied to the pathology. The NP will disturb the communication on the production side by altering the nasal resonance essential in the production for the distinction between oral and nasal sounds but also on the receiver's side who will have difficulties to understand the message.

Thus, preoperatively and postoperatively, the resonant capacities will be disturbed: in the sense of a hyponasality before surgery due to the presence of polyps which will affect the quality of nasal sounds. Then potentially, the risk of a hypernasality after surgery because of the new anatomical configuration. Indeed, there is a diversity of acoustic effects that differ according to the sinuses involved, the nature and type of surgery and the anatomical and physiological specificities of the patient. The alteration of acoustic properties of phonemes after endonasal sinus surgery is diverse and not well known. It is known that NP surgery allows better communication between the sinus and nasal cavities but the real impact on nasal resonances is not known. The same is true for the activity of the vocal folds. There is a link between nasality and voicing, i.e. the vibration of the vocal folds necessary for the production of voiced sounds. Nasality favors voicing. Indeed, to establish voicing, the maintenance of an airflow through the glottic plane is necessary, a passage of air through the nasal cavity facilitates the maintenance of this flow. Preoperatively, since air cannot pass through the nasal cavity, compensatory mechanisms may appear, such as increased voicing or glottic thrust. Thanks to electroglottography, the quality of this voicing preoperatively and postoperatively will be observed.

The NP can therefore be an obstacle to the phenomenon of nasality. Indeed, the airflow in the nasal cavities will be disturbed because of the presence of polyps, which will have consequences on the resonance of these cavities as a whole. This project would provide a deeper understanding of the mechanism of nasal production. It results from the coupling of two cavities: the nasal and oral cavities, which will produce an anti-resonance phenomenon (a resonance phenomenon specific to nasality) and make this resonance process extremely complex. The impact of nasality on the acoustic signal is known (anti-formants etc.) but these manifestations remain diverse and dependent on individual anatomical variability. The impact of the sinuses on speech remains poorly understood today. The controversy between researchers on their influence on speech, encourages us to better explore their role in speech. But also to analyze the phenomenon of resonance before and after surgery to understand the consequences on speech intelligibility and the predictability of the consequences on the speech of patients postoperatively.

Understanding dysfunction in the context of NP will allow us to learn more about the functioning and production mechanisms of nasality in general.