This study investigated the relationship between scores on standardized tests (Clinical Evaluation of Language Fundamentals [CELF], Peabody Picture Vocabulary Test-Third Edition [PPVT-III], and Expressive Vocabulary Test) and measures of spontaneous speech (mean length of utterance [MLU], Index of Productive Syntax, and number of different word roots [NDWR]) derived from natural language samples obtained from 44 children with autism between the ages of 4 and 14 years old. The children with autism were impaired across both groups of measures. The two groups of measures were significantly correlated, and specific relationships were found between lexical-semantic measures (NDWR, vocabulary tests, and the CELF lexical-semantic subtests) and grammatical measures (MLU, and CELF grammar subtests), suggesting that both standardized and spontaneous speech measures tap the same underlying linguistic abilities in children with autism. These findings have important implications for clinicians and researchers who depend on these types of language measures for diagnostic purposes, assessment, and investigations of language impairments in autism. Keywords autism; spontaneous speech measures; standardized language tests; MLU; NDWR Researchers and clinicians regularly rely on a variety of measures of language to assess and chart developmental changes in language in a variety of populations. Clinicians typically depend on measures of language to diagnose children with language impairments, to assess a range of language skills, and to design and monitor treatment programs. Researchers use language measures to define their participant populations, to document their participants' language status, to match groups of participants, or to investigate aspects of language impairment in different populations. Typically, two classes of measures are used for these purposes: (a) standardized psychometric tests and (b) measures of spontaneous speech derived from natural language samples, which can be collected in a variety of ways in different contexts.Both types of measures may be used to assess a range of language skills, including phonology, lexical knowledge, semantics, morphosyntax, and pragmatics, in children at different ages. Generally, standardized language measures assess both receptive and expressive abilities, whereas measures of spontaneous speech are used to tap expressive language. Psychometric tests are norm-referenced, and when administered according to the standardized procedures
NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript defined for them, they provide a relatively quick means for comparing a child to age-matched peers. When tests have been normed on similar samples, they also allow one to compare a child's performance across different tests to yield a profile of language performance across language domains. In contrast, measures derived from natural language samples require a significant investment of time. These measures provide an index of the child's use of language in everyday info...