Changes in Oral Vowel Sounds and Hyoid Bone Movement After Thyroidectomy

OBJECTIVES: Voice and speech alterations after total thyroidectomy may be associated with other extralaryngeal factors, such as neck muscle dysfunction and neck scar contracture. We evaluated the acoustic characteristics of oral vowel sounds and changes in hyoid bone movement before and after thyroidectomy. METHODS: Twenty-nine female patients undergoing total thyroidectomy were included. Fundamental frequencies (Fo), formants and vowel space areas were evaluated before surgery and 7 days and 3 months after surgery to acoustically analyze the oral vowel sounds. Videofluoroscopic images were taken at the same times to evaluate hyoid bone movement. RESULTS: The Fo levels of seven vowels decreased significantly after surgery. The vowel formant changes the F1 of vowel /[e]/ decreased significantly from baseline at 3 months postoperatively, and the F3 of vowel /[i]/ decreased significantly from baseline 7 days postoperatively. The change in the vowel space area was not observed. The Y coordinate of the vowels /[i]/ and /[e]/ decreased significantly from baseline 7 days postoperatively due to changes in hyoid movement. CONCLUSION: The damage to the neck muscles after thyroidectomy changes in Fo, formant and hyoid bone position. These quantitative results could be used as basic data for voice management in patients who undergo thyroidectomy.

Neurophysiology of Laryngopharyngeal Reflux and Brainstem Reflex

Laryngopharyngeal reflux disease (LPRD) is different with gastroesophageal reflux disease (GERD). The lower esophageal sphincter (LES) possesses an intrinsic nervous plexus that allows the LES to have a considerable degree of independent neural control. Sympathetic control of the LES and stomach stems from cholinergic preganglionic neurons in the intermediolateral column of the thoracic spinal cord (T6 through T9 divisions), which impinge on postganglionic neurons in the celiac ganglion, of which the catecholaminergic neurons provide the LES and stomach with most of its sympathetic supply. Sympathetic regulation of motility primarily involves inhibitory presynaptic modulation of vagal cholinergic input to postganglionic neurons in the enteric plexus. The magnitude of sympathetic inhibition of motility is directly proportional to the level of background vagal efferent input. Recognizing that the LES is under the dual control of the sympathetic and parasympathetic nervous systems, we refer the reader to other comprehensive reviews on the role of the sympathetic and parasympatetic control of LES and gastric function. The present review focuses on the functionally dominant parasympathetic control of the LES and stomach via the dorsal motor nucleus of the vagus.

The Perceptual and Consonant Analysis for the Voice with Hypothyroidism

BACKGROUND AND OBJECTIVES: The main purpose of this study is to clarify perceptual and acoustic analysis for the patients with hypothyroidism after thyroidectomy especially focused on the characteristics of speech articulation with special reference to the consonant production. MATERIALS AND METHODS: The subjects of the research were 40 male and female adults (males : 5, females : 35). They were all received radioactive iodine treatment which after total thyroidectomy. Voice samples were collected during the three stages of after surgery, pre-radioisotope treatment (RIT), and post-RIT. The acoustic analysis was conducted by using Pratt (ver.5.2.21) after measuring voice onset time (VOT). The subjective evaluation of the voices used CAPE-V. RESULTS: A significant decrease in overall severity was displayed in the CAPE-V following RIT. It may be conjectured that this is connected to the change in voice following RIT. The loudness of the sound displayed a significant decrease in the CAPE-V following RIT. It is conjectured that this is connected to the decrease in vocal intensity following RIT. No statistically significant results were revealed for the comparative analysis on the voice onset time (VOT) in all plosives during the three periods. CONCLUSION: Perceptually, the overall severity of the voice with hypothyroidism was changed significantly before and after RIT. Eventhough VOT were not significantly changed, it tended to decrease VOT in patients with hypothyroidism.