Effect of Palatal Prosthesis on Few Spectral Parameters of Speech in Cleft Lip and Palate: a Case Study

Abstract

Rehabilitation of speech disorders in the cleft lip and palate population requires teamwork of plastic surgery, palatal prosthesis, and behavioral therapy. The present study is an ttempt to provide an insight on the effect of the palatal prosthetic management in cleft lip and palate. Systematic outcome studies of the effectiveness of palatal prosthetic appliances are required to document towards the evidence based practice. The study is aimed to investigate the acoustical parameters (Energy concentration, formant frequencies F1 and F2.) of speech with (during various stages of preparation) and without palatal prosthesis and to compare with the acoustic parameters of the control subject. This study also examines the velopharyngeal closure with and without using the palatal prosthesis. Materials used for acoustic analysis are repetition of three unaspirated stop consonants in the context of vowel /a/ was considered as the stimuli (/pa/, /ṭa/, and /ka/) and for physiological analysis image of the velopharyngeal closure of the phonation of /a/ was considered. The individual, aged 7 years male with huge palatal fistula was recommended for palatal prosthesis by the cleft palate team members. Age and gender matched control subject was considered as a control subject in the study. The experimental subject was fitted with the palatal obturator and extension and elevation of the prosthesis was provided in various stages to achieve the velopharyngeal closure. Pratt software was used to extract the spectral aspects of speech during the stages. Velopharyngeal closure was evaluated using nasoendoscopy. The acoustic parameters were extracted before and after fitting at various stages of fitting of prosthesis with different elevation or extension of the obturator and compared with normal subject. The result indicates difference in F1, F2 and energy concentration between the control subjects. The variation in formants was also observed with and without prosthesis.