Veränderung der Nasalanz nach Le Fort-I Osteotomie

Impact of orthognathic surgery on voice and speech: a systematic review and meta-analysis

BACKGROUND

Orthognathic surgical procedures, whether in one or both jaws, can affect structures regarding the articulation and resonance of voice and speech.

OBJECTIVE

Evaluating the impact of orthognathic surgery on voice and speech performance in individuals with skeletal dentofacial disharmony.

SEARCH METHODS

Word combinations and truncations were adapted for the following electronic databases: EMBASE, PubMed/Medline, Scopus, Web of Science, Cochrane Library, and Latin American and Caribbean Literature in Health Sciences (LILACS), and grey literature.

SELECTION CRITERIA

The research included studies on nonsyndromic adults with skeletal dentofacial disharmony undergoing orthognathic surgery. These studies assessed patients before and after surgery or compared them with individuals with good facial harmony using voice and speech parameters through validated protocols.

DATA COLLECTION AND ANALYSIS

Two independent reviewers performed all stages of the review. The Joanna Briggs Institute tool was used to assess risk of bias in the cohort studies, and ROBINS-I was used for nonrandomized clinical trials. The authors also performed a meta-analysis of random effects.

RESULTS

A total of 1163 articles were retrieved after the last search, of which 23 were read in full. Of these, four were excluded, totalling 19 articles for quantitative synthesis. When comparing the pre- and postoperative periods, both for fundamental frequency, formants, and jitter and shimmer perturbation measures, orthognathic surgery did not affect vowel production. According to the articles, the main articulatory errors associated with skeletal dentofacial disharmonies prior to surgery were distortions of fricative sounds, mainly/s/ and/z/.

CONCLUSIONS

Orthognathic surgery may have little or no impact on vocal characteristics during vowel production. However, due to the confounding factors involved, estimates are inconclusive. The most prevalent articulatory disorders in the preoperative period were distortion of the fricative phonemes/s/ and/z/. However, further studies must be carried out to ensure greater robustness to these findings.

REGISTRATION

PROSPERO (CRD42022291113).

Changes of some functional speech disorders after surgical correction of skeletal anterior open bite

Skeletal anterior open bite (AOB) or apertognathism is characterized by the absence of contact of the anterior teeth and affects articulation parameters, chewing, biting and voice quality. The treatment of AOB consists of orthognatic surgical procedures. The aim of this study was to evaluate the effects of treatment on voice quality, articulation and nasality in speech with respect to skeletal changes. The study was prospective; 15 patients with AOB were evaluated before and after surgery. Lateral cephalometric x-ray parameters (facial angle, interincisal distance, Wits appraisal) were measured to determine skeletal changes. Before surgery, nine patients still had articulation disorders despite speech therapy during childhood. The voice quality parameters were determined by acoustic analysis of the vowel sound /a/ (fundamental frequency-F0, jitter, shimmer). Spectral analysis of vowels /a/, /e/, /i/, /o/, /u/ was carried out by determining the mean frequency of the first (F1) and second (F2) formants. Nasality in speech was expressed as the ratio between the nasal and the oral sound energies during speech samples. After surgery, normalizations of facial skeletal parameters were observed in all patients, but no statistically significant changes in articulation and voice quality parameters occurred despite subjective observations of easier articulation. Any deterioration in velopharyngeal insufficiency was absent in all of the patients. In conclusion, the surgical treatment of skeletal AOB does not lead to deterioration in voice, resonance and articulation qualities. Despite surgical correction of the unfavourable skeletal situation of the speech apparatus, the pre-existing articulation disorder cannot improve without professional intervention.

Comparison between perceptual assessments of nasality and nasalance scores

BACKGROUND

There are different reports of the usefulness of the Nasometer™ as a complement to listening, often as correlation calculations between listening and nasalance measurements. Differences between findings have been attributed to listener experience and types of speech stimuli.

AIMS

To compare nasalance scores from the Nasometer with perceptual assessments, for the same and different Swedish speech stimuli, using three groups of listeners with differing levels of experience in judging speech nasality.

METHODS & PROCEDURES

To compare nasalance scores and blinded listener ratings of randomized recordings using three groups of listeners and two groups of speakers. Speakers were either classified as having hypernasal speech or speech with typical speech resonance. Listeners were speech-language pathologists (SLPs) working predominantly with resonance disorders, other SLPs and untrained listeners.

OUTCOMES & RESULTS

Correlations (r(s)) between hypernasality ratings and nasalance scores for each listener group and speech stimuli were calculated. For both groups of SLPs all correlations between perceptual ratings and nasalance scores were significant at p= 0.01. The correlations between the nasalance scores and ratings by listeners in the SLP groups were higher than those for the untrained listener group regardless of stimulus type. Post-hoc Mann-Whitney U-tests showed that the only difference that was significant was expert SLP group versus untrained listener group. Secondly, correlations between perceptual ratings and oral stimulus nasalance scores were higher when the perceptual ratings were based on spontaneous speech rather than on the oral stimulus. However, a Wilcoxon signed rank test showed that the difference was not significant. A third finding was that correlations between oral stimulus nasalance scores and perceptual scores were higher than those between mixed stimulus nasalance scores and perceptual scores. A Wilcoxon signed rank test showed that the difference was significant.

CONCLUSIONS & IMPLICATIONS

The Nasometer might be useful for the SLP with limited experience in assessing resonance disorders in differentiating between hyper- and hyponasality. With listener reliability for ratings of hypernasality still being an issue, the use of a nasalance score as a complement to the perceptual evaluation will also aid the expert SLP. It will give an alternative way of quantifying speech resonance and might help in especially hard to judge cases.

The relation of nasality and nasalance to nasal port area based on a computational model

OBJECTIVE

The purpose of this study was to examine the relation of perceptual ratings of nasality by experienced listeners, measures of nasalance, and the size of the nasal port opening for three simulated English corner vowels, /i/, /u/, and /a/.

DESIGN

Samples were generated using a computational model that allowed for exact control of nasal port size and a direct measure of nasalance. Perceptual ratings were obtained using a paired-stimulus presentation.

PARTICIPANTS

Five experienced listeners.

MAIN OUTCOME MEASURES

Measures of nasalance and perceptual nasality ratings.

RESULTS

Differences in nasalance and perceptual ratings of nasality were noted among the three vowels, with values being greater for the high vowels /i/ and /u/ compared to the low vowel /a/. Listeners detected nasality for the high and low vowels simulated with nasal port areas of 0.01 and 0.15 cm(2), respectively. Correlations between ratings of nasality and nasalance were high for all three vowels.

CONCLUSIONS

Results of the present study show a high correlation between ratings of nasality and measures of nasalance for nasal port areas ranging from 0 to 0.5 cm(2). The correlations were based on sustained vowel samples. The restricted speech sample limits generalization of the findings to clinical data; however, the results are a demonstration of the usefulness of modeling to understand the perceptual phenomena of nasality.