title: Information processing speed as a predictor of IQ in children with and without specific language impairment in grades 3 and 8.
abstract: OBJECTIVE
  This study investigated (1) whether nonlinguistic processing speed predicts nonverbal IQ in TD children and children with SLI and (2) if the proposed relationship is different at two time points.
  
  
  METHODS
  The participants consisted of a subset of a longitudinal dataset, 55 typically developing children and 55 children with SLI. Children completed four nonverbal speed tasks and four subtests of the WISC-III. The WISC-III subtests requiring timed and untimed responses were examined separately.
  
  
  RESULTS
  Linear mixed model analyses indicated that in both groups, processing speed predicted nonverbal IQ subtests that reward speedy responses, but not IQ subtests that do not. The relationships between processing speed and IQ with speed bonuses did not differ at grades 3 and 8, and these relationships also were not significantly different in children with SLI and their TD peers.
  
  
  CONCLUSIONS
  The results suggest that the presence of processing speed limitations in many children with SLI raises questions about the utility of timed nonverbal IQ measures as tools for diagnosis of SLI. Future studies should investigate other cognitive assessments that could be used as inclusionary criteria for SLI.
  
  
  OBJECTIVE
  The reader will be able to (1) describe the relationship between processing speed and nonverbal IQ in children with TD and SLI and (2) discuss problems using an IQ criterion to diagnose children as having SLI.
authors.affiliation: The Pennsylvania State University, Communication Sciences and Disorders, United States. Electronic address: jzp151@psu.edu.
authors.forename: Jisook
authors.initials: J
authors.lastname: Park
authors.affiliation: The University of Toronto, Speech-Language Pathology, Canada.
authors.forename: Elina
authors.initials: E
authors.lastname: Mainela-Arnold
authors.affiliation: The Pennsylvania State University, Communication Sciences and Disorders, United States.
authors.forename: Carol A
authors.initials: CA
authors.lastname: Miller
mesh_terms: D000367:Age Factors; D016022:Case-Control Studies; D002648:Child; D005260:Female; D006801:Humans; D007360:Intelligence; D007805:Language Development Disorders / Q000523:psychology*; D007807:Language Tests; D008137:Longitudinal Studies; D008297:Male; D008606:Mental Processes; D011930:Reaction Time; D014888:Wechsler Scales
keywords: IQ; Processing speed; Specific language impairment