A systematic review on diagnostic procedures for specific language impairment: The sensitivity and specificity issues

BACKGROUND: Identification of children with specific language impairment (SLI) has been viewed as both necessity and challenge. Investigators and clinicians use different tests and measures for this purpose. Some of these tests/measures have good psychometric properties, but it is not sufficient for diagnostic purposes. A diagnostic procedure can be used for identification a specific population with confidence only when its sensitivity and specificity are acceptable. In this study, we searched for tests/measures with predefined sensitivity and specificity for identification of preschool children with SLI from their typically developing peers. MATERIALS AND METHODS: A computerized search in bibliographic databases from 2000 to August 2015 was performed with the following keywords: “specific language impairment” or SLI” and “primary language impairment” or ‘PLI’ with at least one of the followings: “diagnosis,” “identification,” “accuracy,” “sensitivity,” and “specificity.” In addition, the related citations and reference lists of the selected articles were considered. RESULTS: The results of reviewing 23 included studies show that the index measures used in studies vary in accuracy with the sensitivity ranging from 16% to 100% and the specificity ranging from 14% to 100%. CONCLUSION: These varieties in sensitivity and specificity of different tests/measures confirm the necessity of attention to the diagnostic power of tests/measures before their use as diagnostic tool. Further, the results indicate there are some promising tests/measures that the available evidence supports their performances in the diagnosis of SLI in preschool-aged children, yet the place of a reference standard for the diagnosis of SLI is vacant among investigations.