New measurement techniques for the assessment of velopharyngeal function in cleft palate patients

The present day treatment of the cleft palate is very much a multi-disciplinary team approach calling upon the skills of plastic surgeon, orthodontist, maxillo-facial surgeon and speech therapist. The aesthetic result of modern plastic surgery on the lip and face is unquestionably successful; however the improvement to speech due to changes in velopharyngeal function as a result of surgery is not so readily agreed upon. It is generally acknowledged that cleft repair should be carried out as early as possible after birth followed by several years of developmental monitoring; however considerable debate relating to the surgical technique employed and the long term effect of surgery on speech development still abounds.

This thesis undertakes to make a contribution to the debate of efficacy of cleft repair in relation to speech function in the following manner. Firstly a new instrument called a Nasal Resonometer has been specifically designed for use by speech therapists for the pre and post operative assessment of hyper- and hypo-nasal speech. Secondly a new measurement technique involving the computer assisted analysis of x-ray videofluoroscopy images of clinically significant aspects of velar function has been introduced.

Several studies of patients attending the clef repair clinics over a three year period are presented. The correlations between objective Resonometer measurement, subjective speech therapist analysis, velopharyngeal function and surgical technique are examined.

The extensive clinical use of the Nasal Resonometer and image analysis technique have proven to be a successful addition to routine cleft palate measurements. Further the application of these measurements in specific studies has led to a clearer understanding of the effect of cleft palate surgery and has highlighted future areas of research.