The Language Delay in Preschool Children with Autism Spectrum Disorder with and without IQ Discrepancy
Objectives: The aims of the study were to establish whether 1) a group difference existed in the language delay among preschool-age children with ASD with different levels of IQD; 2) an association existed between IQD and language delay.
Methods: A total of 127 preschool children with ASD were divided into three groups according to the size of the IQD: EVEN IQ (n=90; IQD within 1 SD), discrepantly higher VIQ (n=14; VIQ > PIQ above 1SD [≥ 15 points]), and discrepantly higher PIQ (n=17; PIQ > VIQ above 1SD [≥ 15 points]). Children with ASD were assessed with the Language Disorder Scale of Preschoolers (LDS) and Wechsler Preschool and Primary Scale of Intelligence™ – Fourth Edition (WPPSI™-IV) respectively to measure their language disability and determine their IQD. The LDS contains three subtests: overall language ability, listening comprehension, and oral expression. Each subtest could differentiate three groups: normal, borderline, and delayed. Chi-square tests were used to examine the relationships between IQD and language delay.
Results: The results indicated significant differences among the three subgroups (p < 0.05) in the LDS. The results of the LDS show that 75 children had language delay in overall language ability (62.0%); 54 children in listening comprehension (44.6%); and 66 children in oral expression (54.6%). The FIQ, VIQ, PIQ, and IQD in the WPPSI-IV were 77.47 (SD = 35.65), 77.80 (SD = 14.89), 78.58 (SD = 16.27), and 10.49 (SD = 8.93) respectively, all of which were below the FIQ of 100 in the psychometric curve. Chi-square tests showed that IQD was related to children’s overall language ability, listening comprehension, and oral expression (X2 = 17.30, df = 4, p = .002; X2 = 19.59, df = 4, p = .001; X2 = 15.30, df = 4, p = .004). Children with even IQD showed better language ability than did children with discrepantly higher VIQ or PIQ. Moreover, children with discrepantly higher VIQ were associated with better language ability than were children with discrepantly higher PIQ, and vice versa.
Conclusions: The results of this study showed that IQD was significantly associated with language delay in children with ASD. The results of this study could encourage clinicians, educators, and therapists to consider IQD when measuring children’s language function and to analyze the patterns of language disability in preschool children with ASD. Possible language problems of children with ASD may be detected early based on routine evaluation of cognitive profiles. Furthermore, the language delay could be explained in terms of IQD. Professionals should pay attention to children’s language problems when they have IQD.