Construct-related validity of the TOCS measures: comparison of intelligibility and speaking rate scores in children with and without speech disorders.

UNLABELLED: This study evaluated construct-related validity of the Test of Children's Speech (TOCS). Intelligibility scores obtained using open-set word identification tasks (orthographic transcription) for the TOCS word and sentence tests and rate scores for the TOCS sentence test (words per minute or WPM and intelligible words per minute or IWPM) were compared for a group of 15 adults (18-30 years of age) with normal speech production and three groups of children: 48 3-6 year-olds with typical speech development and neurological histories (TDS), 48 3-6 year-olds with a speech sound disorder of unknown origin and no identified neurological impairment (SSD-UNK), and 22 3-10 year-olds with dysarthria and cerebral palsy (DYS). As expected, mean intelligibility scores and rates increased with age in the TDS group. However, word test intelligibility, WPM and IWPM scores for the 6 year-olds in the TDS group were significantly lower than those for the adults. The DYS group had significantly lower word and sentence test intelligibility and WPM and IWPM scores than the TDS and SSD-UNK groups. Compared to the TDS group, the SSD-UNK group also had significantly lower intelligibility scores for the word and sentence tests, and significantly lower IWPM, but not WPM scores on the sentence test. The results support the construct-related validity of TOCS as a tool for obtaining intelligibility and rate scores that are sensitive to group differences in 3-6 year-old children, with and without speech sound disorders, and to 3+ year-old children with speech disorders, with and without dysarthria. LEARNING OUTCOMES: Readers will describe the word and sentence intelligibility and speaking rate performance of children with typically developing speech at age levels of 3, 4, 5 and 6 years, as measured by the Test of Children's Speech, and how these compare with adult speakers and two groups of children with speech disorders. They will also recognize what measures on this test differentiate children with speech sound disorders of unknown origin from children with cerebral palsy and dysarthria.