Factors affecting speech in patients with isolated cleft palate. A methodic, clinical and instrumental study.

The present study deals with various factors affecting speech, particularly its resonance, in patients with isolated cleft palate. For that purpose a method to evaluate hypernasality was developed. The degree of hypernasality was assessed in terms of hypernasality indexes by means of a modified cul-de-sac hypernasality test. The phonetic content of the test words was chosen so as not to bias the evaluations by compensatory articulations. The reliability and validity of four variations of hypernasality indexes were examined. All these four indexes proved reliable, valid and feasible for evaluating hypernasality. The hypernasality indexes were compared with nasalance scores derived from the Model 6200 Nasometer (The Nasometer 1987, Fletcher et al. 1989). Reference nasalance scores for normal Finnish speech were measured. The mean percent nasalance and the standard deviation were 13 and 8, respectively. In addition to the present hypernasality test modification, more traditional descriptive speech analysis was used in some studies. The effect of the age at primary palatal repair on speech was examined in three year old children with isolated cleft palate. The effect on speech of two techniques for primary palatal repair - a Veau-Wardill-Kilner V to Y push back procedure and the Cronin modification - were compared in young adults with isolated cleft palate. The effect on speech of two techniques for a secondary velopharyngeal flap - a Sanvenero-Rosselli and modified Honig flap - were compared in patients with various ages and cleft types. One third had cleft lip and palate or submucous cleft palate. The rest had isolated cleft palate. The quality of speech was significantly dependent on the age at primary palatal repair. The children, whose palatal repair was performed at the average age of 22 months demonstrated, significantly more frequently, hypernasality and misarticulations related to velopharyngeal insufficiency than the children operated upon earlier. The children operated upon between the average ages of 12-18 months, demonstrated normal speech in about 3/4 of the cases. If the palate was operated on later, about 1/4 of the patients demonstrated normal speech. The technique for primary palatal repair had a significant influence on the quality of speech. Hypernasality assessed in terms of hypernasality indexes was less frequent in the speech of patients with the Cronin modification than with the Veau-Wardill-Kilner push back procedure. The technique for the secondary velopharyngeal flap also affected speech significantly. The patients with a modified Honig velopharyngeal flap eliminated more efficiently hypernasality from their speech than those with a Sanvenero-Rosselli flap.(ABSTRACT TRUNCATED AT 400 WORDS)