Effect of Cleft Type on Overall Speech Intelligibility and Resonance

The main purpose of this study was to measure and compare the effect of an unilateral cleft lip and palate (UCLP) and a bilateral cleft lip and palate (BCLP) on overall speech intelligibility, nasalance and nasality. An additional objective was to compare the nasalance and nasality patterns of cleft palate children with the available normative data for normal children. The subjects were 37 children with an UCLP (19/37) or a BCLP (18/37) with normal cognitive and motor functions and normal hearing levels. All subjects had a non-syndromic cleft, followed the same surgical protocol and did not undergo secondary pharyngeal surgery. To measure and compare the effect of cleft type, objective and subjective assessment techniques were used. For the objective assessment of nasal resonance the nasometer and the mirror-fogging test were used. Nasalance scores were obtained, while patients produced sounds, read three standard passages or repeated sentences focusing on specific consonants. A perceptual evaluation of speech, the Gutzmann (1913) test and the tests of Bzoch (1989) were used as subjective assessment techniques. The perceptual assessment of the overall speech intelligibility was based on the spontaneous speech and reading or repeating of the nasometric sentences. These samples were judged by three speech pathologists using a 4-category nominal scale. A subjective test (Morley, 1945) was used to evaluate the velopharyngeal mechanism. The findings of the present study show no statistically significant differences for nasalance values, nasality and overall speech intelligibility between the UCLP and BCLP children. Significant differences were found between the data of the normal group and the cleft palate children. These differences included nasalance values as well as nasality data and overall speech intelligibility.