A comparison of receptive-expressive language profiles between toddlers with autism spectrum disorder and developmental language delay

Abstract

Purpose: It is well known that expressive language impairment is commonly less severe than receptive language impairment in children with autism spectrum disorder (ASD). However, this result is based on experiments in Western countries with Western language scales. This study tries to find whether the result above is applicable for toddlers in a non-Western country; more specifically, in Korea with non-Western language scales.

Materials and methods: The participants were 166 toddlers aged between 20 months and 50 months who visited the clinic from December 2010 to January 2013. The number of toddlers diagnosed as ASD and developmental language delay (DLD) was 103 and 63, respectively. Language development level was assessed using Sequenced Language Scale for Infants (SELSI), a Korean language scale. Using SELSI, each group was divided into 3 sub-groups. Moreover, the group difference by age was observed by dividing them into three age groups. Chi-square test and linear-by-linear association was used for analysis.

Results: Receptive language ability of the DLD group was superior to that of the ASD group in all age groups. However, expressive language ability in both groups showed no difference in all age groups. A greater proportion of expressive dominant type was found in ASD. The 20-29 months group in ASD showed the largest proportion of expressive language dominant type in the three age groups, suggesting that the younger the ASD toddler is, the more severe the receptive language impairment is.

Conclusion: These findings suggest that receptive-expressive language characteristics in ASD at earlier age could be useful in the early detection of ASD.

Keywords: Autism spectrum disorder; expressive language; receptive language; toddlers.

Fig. 1

Distribution of dominant type by diagnosis. (A) ASD group was composed of 44 (42.7%) toddlers with ED, 28 (27.2%) with ND, and 31 (30.1%) with RD. (B) DLD group was composed of 7 (11.1%) toddlers with ED, 18 (28.6%) with ND, and 38 (60.3%) with RD. (C) In total, there were 51 (30.7%) ED, 46 (24.7%) ND, and 69 (41.6%) RD. Significant group difference in proportion was observed between ASD and DLD group using chi square test (χ²=21.327, p<0.001). ASD, autism spectrum disorder; DLD, developmental language delay; ED, expressive language dominant type; ND, non-dominant type; RD, receptive language dominant.

Fig. 2

Distribution of each dominant type by age group and by diagnosis. (A) Distribution of each dominant type by age group in ASD. In comparison with type by age group chi-square test within ASD group, proportions of dominant types were significant differences between the 20-29 M and 40-49 M age groups and between the 30-39 M and 40-49 M age groups (20-29 M-40-49 M: χ²=8.433, p<0.014, 30-39 M-40-49 M: χ²=8.251, p<0.017). There is no significant difference between 20-29 M and 30-39 M age groups. (B) Distribution of dominant type by age groups in DLD. Using the same analysis method described above, there was significant difference between the 20-29 M and the 40-49 M age groups in DLD (χ²=7.274, p<0.021). In contrast to ASD, there is no significant association in DLD. When compared to inter-group, a significant group difference was identified in the 20-29 M, 30-39 M age group between ASD and DLD (20-29 M: χ²=11.930, p<0.002, 30-39 M: χ²=19.302, p<0.001). ASD, autism spectrum disorder; DLD, developmental language delay; RD, receptive language dominant type; ND, non-dominant type; ED, expressive language dominant type.

Fig. 3

Distribution of expressive language dominant type and expressive language non-dominant type by age-group in ASD group. The younger the age group, the higher proportion of expressive language dominant type was shown in ASD than in DLD by linear association (χ² for linear trend p<0.006). ED, expressive language dominant type; Non-ED, expressive language non-dominant type; ASD, autism spectrum disorder; DLD, developmental language delay.