Predictive value of hyoid cephalometrics for retroglossal obstruction in patients with obstructive sleep apnoea hypopnea syndrome.

OBJECTIVE: To examine the diagnostic value of hyoid cephalometrics in predicting retroglossal obstruction severity in patients with obstructive sleep apnoea hypopnea syndrome. METHODS: Ninety-six obstructive sleep apnoea hypopnea syndrome patients diagnosed by polysomnography were recruited. Polysomnography was repeated with a nasopharyngeal tube after eliminating rhinal and palatopharyngeal obstruction. Cervical vertebra lateral films and hyoid cephalometric measurements were obtained, including the distances of the hyoid to the: mental tubercle, prevertebral plane, mental tubercle coronal plane and mental tubercle horizontal plane. RESULTS: The apnoea-hypopnoea index for nasopharyngeal tube polysomnography was significantly correlated with distances from the hyoid to: prevertebral plane (r = 0.350), coronal plane (r = 0.477), horizontal plane (r = 0.529) and mental tubercle (r = 0.560). It was strongly correlated with the hyoid to mental tubercle distance/hyoid to prevertebral plane distance value (r = 0.683), and (hyoid to coronal plane distance plus hyoid to horizontal plane distance)/hyoid to prevertebral plane distance value (r = 0.675). CONCLUSION: Obstructive sleep apnoea hypopnea syndrome patients with longer hyoid to mental tubercle distances, and/or more inferior and posterior hyoid bone position, are more prone to retroglossal stenosis and obstruction. Hyoid cephalometrics are valuable for predicting retroglossal obstruction severity.

Effect of early postnatal air-conduction auditory deprivation on the development and function of the rat spiral ganglion.

OBJECTIVE: To evaluate the effect of early postnatal air-conduction auditory deprivation on the development and function of the rat spiral ganglion. STUDY DESIGN: Randomised animal study. METHODS: Sixty neonatal Sprague-Dawley rats were randomly divided into two groups: controls (n = 30) given regular chow and water ad libitum; and study animals (n = 30) fed within a soundproof chamber. Auditory brainstem response testing was conducted in both groups on postnatal day 42. RESULTS: Auditory deprivation between postnatal days 12 and 42 resulted in an increased hearing threshold and reduced auditory brainstem response amplitudes, together with degeneration of type I spiral ganglion neurons and the presence of apoptotic cells. CONCLUSION: Non-invasive auditory deprivation during a critical developmental period resulted in numerous changes in rat cochlear function and morphology.