Autism Spectrum Disorder (ASD) is a neurodevelopment disorder associated with social communication deficits and restricted and repetitive behaviors (5th ed.; DSM-5; American Psychiatric Association). Children with ASD all expressed deficits in language ability to some extent, but the way in which communication was affected showed great varieties. While some children might grow up being almost non-verbal with few utterances, others are able to develop sophisticated language skills. ASD itself bears such great heterogeneity that one might even argue no two children with ASD demonstrate the same arrangement of symptoms. It is therefore not uncommon to see a wide range of language capacity in the population. However, not much research so far has focused on the contributing factors of the phenomenon, leaving the question answered by the mere restatement of heterogeneity. I am thus very interested in redirecting the reader’s attention to the question and approach the variety in language profiles from both the perspectives of environmental factors and neurodevelopment deficits.
The symptoms of ASD, particularly the inattentiveness to the environment and the language deficit, was initially attributed to “refrigerator motherhood”(Waltz, 2015). Women were accused of being loveless and cold around their children, causing atypical behaviors including speech deficiency. The modernization of etiology has proven the partiality of such a biased statement, yet parents as direct caretakers of children with autism do have a crucial role in facilitating the development of language. Crandall et al. (2019) explored the relationship between early parent input and later expressive verb vocabulary in children with ASD. By observing videos and parental reports of expressive verb vocabulary, the 2019 longitudinal study was among the very few studies that focused on the effect of specific parent input (i.e.verb input). Given the importance of verb vocabulary in forming efficient and grammatically correct sentences, the researchers attended to the potential of verb vocabulary accumulation in enhancing language and learning ability in children with ASD. Taking into account three main aspects of parental input, namely quantity, diversity, and grammatical informativeness, the researchers operationalized parents’ general tendency of using diverse and grammatically informative verbs (i.e. with more verb-related morphosyntactic elements) in follow-in utterances as the Z score-transformed scores of the aforementioned three categories. It’s also worth noticing that the study focused specifically on follow-in utterance rather than general utterance of verb vocabulary. Result of previous research targeting children with typical development suggested that adult verb input immediately after or during a joint attention episode was positively related to the later verb vocabulary of the child (Tomasello & Cale Kruger, 1992). Considering that children with ASD experience difficulties in shifting attention from one visual stimulus to another, the researchers placed their emphasis solely on follow-in utterance of verbs for its immediate response attending to autistic children’s actions. The findings of the study indicated that there existed a significant positive relationship between parents follow-in utterance of verb vocabulary and later expressive verb vocabulary among children. The researchers also tested on the effect of follow-in utterance without verbs on children’s later expressive verb vocabulary and found no significant correlation between the variables. The result suggested that specific parental input matters, demonstrating the strength rather than disadvantage of verb using in facilitating language learning among children with ASD.The study was valuable to not only the exploration of a wide range of language abilities among children with ASD, but it also provided insight in revisiting existing intervention programs that focused primarily on pragmatic language use. Rather than focusing solely on noun phrase elaboration and the adoption of telegraphic phrase which was previously considered as more feasible for children with ASD to use and comprehend, the study presented supportive evidence that verb-related morphosyntactic elements could be similarly if not more beneficial to the language development in the population.
Despite the specificity and uniqueness of the topic, the study did not control for parents’ IQ, educational or socioeconomic background when selecting the participants. An alternative thus arises to explain the result of the study. Parents who have higher IQ or are privileged to have more time talking to their children could possibly have a higher tendency in using more diverse verbs or simply using verbs more often. Children whose parents are more intelligent might also have a potential advantage in verb acquisition over members of the same cohort given the heritability of IQ. Children whose parents could afford the time commitment to intervention programs might also have more other resources that could aid language learning as compared to those whose parents cannot, including more educated sitters or private tutors. I am therefore reluctant to attribute the differences in later expressive verb vocabulary completely to parental input. It is necessary for future studies to take the confound variable of IQ and socioeconomic background into consideration by exploring their relationship with the frequency of parental diverse verbal input. Additionally, the study did not take non-verbal children with ASD into account. In other words, the study raised the possibility of learning in a sample where participants were already showing signs of fruitful learning in the first place, leaving out children whose language ability was severely restricted given their incapacity in typical language acquisition. The significance of zero to one was left unexplored in the course of language development, which demands more attention in answering the other half of the question—why do some children with ASD develop verbal language while others do not?
Arnett et al. (2018) in a study that examined the relationship between auditory perception, implicit language learning and receptive language ability complemented the aforementioned 2019 study by including children with distinct language profiles (i.e. receptive language skill range = 20-139). The study was unique in that it did not “rely on any previous lexical or semantic knowledge, nor did it require a response that was dependent on motor or working memory abilities,” (Arnett et al., 2018, pp.8) which otherwise would have immediately ruled out participants with very low cognitive and language skills. The exclusion could result in a skewed mapping of neural circuitry and language processing abilities. The study also complemented the 2019 study by Crandall et al. in that it provided analysis from a more basic level of language acquisition. The study approached language deficits in ASD through its high correlation with atypical auditory processing (Kuhl et al., 2005). Auditory perception as a key element in statistical learning allowed children to recognize repetitive patterns and then directs their attention to frequently appeared objects/actions in the surrounding, which aid the encoding of information. Before even diving into semantic processing, the study emphasized how children with ASD might differ from their typical development counterparts on the perceptual level when exposed to a given sound, thus addressing the evolvement from zero to one in language production.
Children of both typical neurodevelopment and ASD were presented with an artificial language paradigm that was composed of a two-minute continuous stream of English language syllables which was organized pseudo-randomly such that tri-syllabic combinations were statistically compatible to those of learned words (1.0) and unlearned words (0.33) in terms of transitional probabilities (Arnett et al., 2018). Participating children were measured for P1 amplitude, latency, and topography ERP plots through continuous EEG during the task. Results suggested that there existed an association between greater receptive language ability and smaller P1 amplitude to learned versus unlearned words. The finding aligned with previous assertions that smaller P1 amplitudes were associated with a more efficient processing as information becomes more familiar to the recipient. In other words, by recognizing the patterns of familiar sounds, children with ASD who were high on receptive language ability actually displayed signs of learning. It’s worth noticing that the association was strongly predicted by age, nonverbal cognition, and ASD symptoms severity, suggesting the important role of auditory processing in receptive language skills. I, therefore, wonder if the finding implied that for children who experienced severe deficits in audio processing, it would be highly unlikely for even the basic learning to occur later on.
In terms of lateralization, researchers found a lack of left hemisphere specialization, which is associated with language processing in population with typical development during implicit language learning in the studied ASD sample. Atypical lateralization in the ASD cohort, particularly the broader neural circuitry for processing language, was argued to have been possibly practiced at the cost of other non-speech processing resources, including gestures, tone, grammar, etc. This interpretation is particularly relevant for understanding the difficulties children of ASD face when acquiring languages, given that the task of language learning is not a mere imitation of sound, but rather a co-occurrence of gesture, facial expressions, and voice quality. By using an artificial language paradigm, Arnett et al. (2018) successfully eliminated social cues like intonation and stressed syllables and focused solely on the basic level of sound perception. However, social cues as such could be very helpful indicators for children with ASD in a real-life language learning setting. While the researchers kept out social cues as variables for means of experimental control, their importance to meaning acquisition and language learning should not be overlooked in the long run. In addition to that, decreased lateralization in the left hemisphere was not a unique feature for ASD but instead shared across several other conditions that involve language deficits, raising the question of whether the finding of the study shall be attributed to ASD or language development disruption in general.
Focusing on the language ability of children with ASD, the two studies approached the subject from different perspectives, but complemented and complicated each other’s findings. First, the result from neuroimaging (Arnett et al., 2018) seemed to have provided an explanation for the effectiveness of follow-in utterance, given that repetitive immediate response to a novel situation contributes to the familiarization of the word. The finding also supported the facet of quantity in the parental input study. Children whose parents engaged more often in verb utterance were more likely to be repetitively exposed to the same verb, thus increasing the likelihood of later recognition. Second, while neuroimaging captured a moment of development which might explain the relatively hard-wired devices children with ASD were born with, the longitudinal study emphasized the importance of environmental factors and the potential of improving from a soft “realism” standpoint that values external intervention. The two studies tackled separately the qualitative changes from zero to one and one to many in the course of language development.
Crandall et al. (2019) mentioned the difficulty of verb acquisition in comparison to noun acquisition which was explained as influenced by the grammatical weight and relational nature of this category. The fact that verbs rather than nouns benefited children with ASD during follow-in utterance made me wonder about the mechanism underlying such phenomenon. Could the exposure and acquisition of more verbs during the intervention program and familial environment alter neural circuitry in the youth population with ASD? Much as we know about the bidirectional relationship between mind and body and the plasticity of brain tissues at an early age, the extent to which language program could alter atypical neuro-network is very intriguing to me. The way in which a noun was learned through assigning words to objects is much more complicated in the case of verbs when words were not only observed but also enacted. The difficulty in processing the motions along with the phonology could possibly be one of the hardships children with ASD face during verb acquisition. As Arnett et al. (2018) pointed out, the atypical distribution of cognitive resources when processing languages in the ASD population could lead to the deprivation of other resources, including misunderstanding or a total absence of understanding when processing gestures. Would children who were capable of receptive learning and have also been exposed to expressive verbs do a better job in understanding gestures accompanying speech? To answer the question, it is important for future study to focus on the way in which children with early onset of ASD distinguish verb from nouns and other descriptive adjectives so as to see how similar or different verb acquisition happened in ASD population as compared to typical development cohort.
The question targeting the broad range of language ability among children with ASD is one that can’t be answered easily. The differences between verbal and nonverbal children with ASD, as well as those who could attend to grammatical rules and those who could barely make use of pragmatic language, are complicated and demand attention from the field. While children with ASD might have atypical innate statistical learning ability which results in considerable hardship in language acquisition, environmental factors like familial support could still make a big difference. Rather than overly simplifying the way children with ASD use languages, it is time for us to reexamine the way or the many different ways children with ASD acquire languages.
Work Cited:
American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed.). https://doi.org/10.1176/appi.books.9780890425596
Arnett, A. B., Hudac, C. M., DesChamps, T. D., Cairney, B. E., Gerdts, J., Wallace, A. S., & Webb, S. J. (2018). Auditory perception is associated with implicit language learning and receptive language ability in autism spectrum disorder. Brain and Language, 187, 1-8. http://dx.doi.org/10.1016/j.bandl.2018.09.007
Crandall, M. C., McDaniel, J., Watson, L. R., & Yoder, P. J. (2019). The relation between early parent verb input and later expressive verb vocabulary in children with autism spectrum disorder. Journal of Speech, Language, and Hearing Research, 62(6), 1787-1797. http://dx.doi.org/10.1044/2019_JSLHR-L-18-0081
Kuhl, P. K., Coffey-Corina, S., Padden, D., & Dawson, G. (2005). Links between social and linguistic processing of speech in preschool children with autism: Behavioral and electrophysiological measures. Developmental Science, 8(1), F1-F12. http://dx.doi.org/10.1111/j.1467-7687.2004.00384.x
Tomasello, M., & Cale Kruger, A. (1992). Joint attention on actions: Acquiring verbs in ostensive and non-ostensive contexts. Journal of Child Language, 19(2), 311-333. http://dx.doi.org/10.1017/S0305000900011430
Waltz, M. (2015). Review of autism and gender: From refrigerator mothers to computer geeks. Disability & Society, 30(3), 492-494. http://dx.doi.org/10.1080/09687599.2014.995517
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