The Preschool Speech Intelligibility Measure

Impairment of the phonological system is one of the most common communication disorders of young children. In 1971, Milisen estimated that functional articulation disorders make up 75 to 80% of all speech impairments in children. Seventeen years later, the National Institute of Neurological and Communicative Disorders and Stroke concluded that 10 to 15% of all preschoolers had a speech disorder (cited in Shames, Wiig, & Secord, 1994). Despite the relatively high prevalence of phonological problems in young children, no standard procedure exists for quantifying the intelligibility of this group (Kent, Miolo, & Bloedel, 1992, 1994). Even though measures are specifically developed for young children (see Kent et al., 1994, for review) they are not widely used by practicing speech-language pathologists. As a result, the present measure of choice for assessing intelligibility in preschool children appears to be subjective estimation of performance such as assignment of percentage intelligibility (e.g., 50% intelligible, 20% intelligible, etc.) or degree of understandability (e.g., easily understood, understandable if topic is known, some words intelligible, unintelligible) (Peterson & Marquardt, 1994). Kent, Weismer, Kent, & Rosenbek (1989) note that scales such as these offer the “advantage of speed but are only crudely quantitative.” Part of the difficulty in assessing intelligibility is the inherent subjectivity of the phenomenon. Although articulatory accuracy is a key component in determining the understandability of a message, several other factors are also important contributors. As a result, one listener may consider a message completely unintelligible; a second listener, aided by contextual cues, may be able to accurately grasp the general meaning of the same utterance; while a third, more familiar listener, may actually understand most of the individual words. This report describes the development and initial testing of the Preschool Speech Intelligibility Measure (PSIM). The PSIM is a modification of Yorkston and Beukelman’s (1980, 1981) single-word speech intelligibility test for dysarthric adults. The PSIM was designed to be a time efficient, reliable, and objective measure of the intelligibility of young children.