Consistency of Articulation of Subjects with Cleft Palate

Abstract

Early research studies in the field of articulation have indicated that, as a rule, children are inconsistent in their misarticulations of speech sounds. For example, Wellman and associates (13) found that the percent of correct articulatory productions increases as a function of age, as did Roe and Milisen (8). Spriestersbach and Curtis (9), in a review of studies done at The University of Iowa, indicated that individuals who misarticu-lated speech sounds typically do so inconsistently, that the inconsistencies are to be accounted for on a lawful basis, and that a need exists for rather detailed testing of any defective sound. Much of the research examining inconsistency of misarticulation has involved subjects with articulation problems classified as functional rather than those due to some structural deficit, such as cleft palate. There is some information about cleft palate speakers, however. Mc— Williams (5) reports that the articulation of adult patients with cleft palate is highly inconsistent, and that most subjects were able to produce all consonant sounds correctly some of the time. Spriestersbach, Darley, and Rouse (10) also indicated that children with cleft palate tend to be highly inconsistent in articulatory performance. McDermott (4) in his investigation of /s/ production for 54 cleft palate individuals also examined consistency. He concludes that individuals with oral manometer ratios of .90 or better were significantly more consistent in producing a correct /s/ than were subjects with lower manometer ratios. His findings emphasize the importance of such factors as velopharyngeal incompetence, dental configuration, phonetic environment, syllabic function, and rate of utterance. The present study was designed to investigate the use of measures of consistency of articulation proficiency in differentiating subgroups of cleft palate subjects and to examine consistency measures as a tool for clinical diagnosis and prognosis. (Although consistency may be defined in a variety of ways, for the purposes of this study the measure was defined as the percent correct.) The specific question asked was: Do articulation consistency scores vary with manometer ratios, age, severity of articula-tion defectiveness, and manner of production categories for various sub— groups of cleft palate patients?