The effects of surgical rapid maxillary expansion (SRME) on vowel formants

Abstract

The objective of this study was to investigate the effect of surgical rapid maxillary expansion (SRME) on vowel production. The subjects included 12 patients, whose speech were considered perceptually normal, that had undergone surgical RME for expansion of a narrow maxilla. They uttered the following Turkish vowels, ([a], [e], [dotless i], [i], [o], [oe], [u], [y]), in isolation before and after the maxillary expansion. These samples were recorded for acoustical analysis. The fundamental frequencies (F0) and the frequencies and bandwidths of the first two formants (F1 and F2) of the vowels were measured using the Multi-Speech programme (Kay Elemetrics). Statistical analysis revealed that the second formant frequency (F2) and bandwidth values in the vowel [i] and [oe] were lowered after maxillary expansion (p<.05). Surgical RME induced the decrease in the second formant of the [i] and [oe] vowels by affecting the size of the anterior oral cavity, however the influence was too small to cause any differences in the acoustic properties of the other vowels.

Phonetic analysis during treatment with rapid maxillary expander

“…Our findings confirm other studies showing that placement of an orthodontic device causes an immediate reduction in fricative peak frequency. Both fricatives displayed this behaviour at RME placement, and then, the peak frequency gradually increased during therapy.…”

“…These significant changes in palatal morphology may affect speech by modifying the articulation sites of the tongue on the palate and changing the oral resonance mechanism by enlarging the oral cavity. A correct speech pronunciation is related to palate size, and maxillary surgical expansion causes vowel sound modification . The introduction of fixed elements in the oral cavity, such as an artificial palate or orthodontic appliances, alters consonant and vowel articulation …”

Effects of Hawley retainers on consonants and formant frequencies of vowels

“…There are many studies 6,9,10,[20][21][22][23] whose authors have used subjective evaluation of the consonants and vowels and who have reported effects of the orthodontic application on the speech articulation in the literature, whereas fewer studies 13,[24][25][26][27] contained objective assessment of the formant frequencies.…”

The effects of rapid maxillary expansion on voice function

“…In addition, the authors found that the F 1 frequency of the vowel /i/ increased, whereas F 2 and F 3 decreased. Sarı et al 11 investigated the effect of surgical RME on vowel production. The F 2 frequency of the vowels /i/ and [oe] showed a decrease because the vowels were affected by the size of the anterior oral cavity.…”

“…F 1 values vary mostly with changes in tongue height, while F 2 varies mostly with changes in tongue advancement. 11 In 2005, Moura et al found an apparent increase in F 1 frequency among the RME group in their study of Down syndrome patients. According to the authors, this was explained by expansion of the airways caused by RME, enlargement of the vocal tract, and provision of enough space for the tongue.…”