Recognizing Deficits in Infants and Toddlers That May Indicate ASD

In my pediatric practice, I see toddlers from both monolingual and bilingual families who appear to demonstrate symptoms that may indicate a developmental language disorder or a delay in language development. However, they may be exhibiting early symptoms of ASD. Would you provide me with more information about the characteristics of ASD in infants and toddlers and the symptoms they may have in common with a developmental language disorder or delay to assist me in making an informed opinion and appropriate referral?

Answered by Jan M. Downey, MA, CCC-SLP, TSHH
Eden II Genesis Programs
Isabelle Mawby, MD, MA
Department of Pediatrics, Vanderbilt University Medical Center

Some Background

Assisting Pediatricians to Recognize Deficits in Their Infants and Toddlers That May Indicate a Diagnosis of ASD The question you pose is an important one, as pediatricians see infants regularly throughout their first year of development and are in the best position to identify and monitor early symptoms that may be indicative of a later diagnosis of autism spectrum disorder (ASD). This is beneficial as the incidence of ASD has significantly increased over the years and is currently 1 in 36 (Centers for Disease Control and Prevention [CDC], 2023). The American Academy of Pediatrics (Hyman et al., 2020) recommends that all toddlers be screened for ASD between 18 and 24 months of age, with the goal of identifying and providing early intervention services as soon as possible. Furthermore, a diagnosis of a developmental language disorder (DLD) occurs in approximately 7% of the population (Laasonen et al., 2018). Although a variety of terms have been used in the past to refer to children presenting with DLD, such as specific language impairment this article will use DLD to describe those children, and LT to refer to young children who are “late talkers” and present with a delay in language development. DLD is not associated with other neurodevelopmental disorders, such as ASD (Bishop et al., 2016), although verbal toddlers with ASD may exhibit disordered and/or delayed speech. DLD is also not synonymous with solely a delay in language development. An LT toddler will demonstrate the typical order of language acquisition but does so later than their same-aged peers. Approximately 15% of toddlers fall into this category (Camarata, 2014b).

While there are some similarities in infants and toddlers with DLD and ASD with respect to the acquisition of early receptive language skills and nonverbal communication, there are important differences as well. An understanding of the unique behaviors, deficits, and characteristics infants and toddlers exhibit that may indicate a later diagnosis of ASD will guide pediatricians in determining when a referral is warranted. Whether ASD or DLD is suspected, it is imperative for pediatricians to refer their patients to a professional or an agency that specializes in ASD with knowledge and expertise in the symptoms of the disorder and diagnostics.

Differentiating ASD and DLD in Infants and Toddlers

A diagnosis of ASD is over four times more likely in males than females (Camarata, 2014a), but this gender disparity is not the case with those diagnosed later with DLD. ASD occurs in all racial, ethnic, and socioeconomic groups (CDC, 2018). In the United States, approximately 20% of children speak a language other than English at home (American Academy of Pediatrics and American Speech-Language-Hearing Association, 2017). Research indicates that bilingualism does not result in any additional difficulty in language development in children with ASD (Garrido, López, & Carballo, 2021). Please also see this recently published article by ASAT related to working with bilingual families.

Although several studies over the years suggest that White children are more likely than minority children, particularly Hispanic children, to be identified with ASD, pediatricians should not conclude that the disorder occurs at an increased rate in white children. Rather, there are several factors contributing to the decreased recognition of ASD in this population, such as the potential of reduced access to healthcare services, misattribution that language delay is attributed to bilingualism, and other barriers when the primary language is other than English, such as a lack of information or resources. These factors must continue to be considered even though there is some research suggesting that the disparity in identifying ASD between white and Hispanic children is decreasing. Regardless of the race, ethnicity, or sex of the child, the hallmark traits and deficits of ASD are the same.

There are two other points that bear relevance to this conversation with respect to bilingual families. The proportions of bilingual and monolingual children who develop DLD are similar (Byers-Heinlein & Lew-Williams, 2013). Nonetheless, children of bilingual parents are sometimes misdiagnosed with a language delay or disorder when they are simply demonstrating characteristics of a child who is learning two languages.

The Diagnostic Statistical Manual-5 (DSM-5, 2013) indicates that the diagnosis of ASD can now be made in the “early developmental period” as opposed to approximately three years of age. The evidence that supports the efficacy of early intervention (EI) services has driven research to reduce the age at which infants and toddlers may be diagnosed with ASD (Paul et al., 2008). Typically developing (TD) infants, as well as infants who are later identified as LT, exhibit early nonverbal communication and receptive language skills as young as six- to nine-months of age. The absence of these skills may suggest a “red flag” for a future diagnosis of ASD or DLD as the onset of DLD symptoms is also during the “early developmental period” (DSM-5, 2013). The AAP’s recommendation for pediatricians to refer all toddlers between 18- months and two-years of age for an evaluation, perhaps, should be made earlier.

Infants produce a variety of sounds that evolve as they develop. Following cries, coos, and giggles, they will begin to engage in the early developmental stages of babbling at approximately four to six months of age. The more advanced form of babbling emerges afterwards and is referred to as canonical or reduplicated babbling. The infant begins to produce consonant-vowel (CA) combinations, such as “mamama,” “dadada,” “bababa,” etc. Canonical babbling is the last stage of babbling prior to the production of whole words. It is well-developed in TD infants by 10-months of age and is an important milestone for the development of speech (Patten et al., 2014). Some studies suggest that infants who present with a delay or decrease in canonical babbling and/or produce atypical vocalizations may later be diagnosed with ASD (Yankowitz et al., 2022). Pediatricians and parents should observe the infants’ early patterns of vocalizations. While abnormal vocal patterns alone do not indicate ASD, an assessment in this area should be included in overall diagnostics should additional “red flags” be identified. Further research needs to be conducted in this area to glean more information.

There are several nonverbal early communication skills that TD infants, and those who are later identified as LT, exhibit before two-years of age. At six-months old they will turn their head toward sounds they hear and respond when their name is called by turning their head toward the speaker at approximately their first birthday. They begin to use gestures, such as pointing, shaking their heads to indicate “no,” nodding their heads to indicate “yes,” and waving “bye-bye” all by the age of one (Crais, Watson & Baranek, 2008). Infants and toddlers with DLD are also often able to engage in these conventional gestures (Paul et al., 2008).

Joint attention (JA) or shared attention is another early form of nonverbal communication that emerges at approximately nine months of age and typically becomes fully developed before the age of two. Using a gaze, head nod, or pointing a finger, one person signals to another that something of interest is going on and invites the other person to attend to it (Wetherby et al., 2004). For example, the mother may “signal” her infant, using any of the above methods, to an object in the nursery, and the infant will respond instinctively by turning their head or gaze toward that object. Moreover, infants will initiate JA by establishing reference and turning toward the object first to let the mother know that she should also look in the same direction. JA is a core deficit in infants later diagnosed with ASD, but not those identified with DLD or later as LT (Gangi, Ibanez & Messinger, 2013).

Between seven months and one-year of age TD and LT infants and toddlers are continuing to develop their receptive language skills. They will demonstrate an understanding of an increasing number of words that represent items they are often exposed to in their environment, such as a bottle, cup, ball, etc. They respond to simple directions, e.g., “come here” and can predict what will happen next when provided with visual and/or auditory cues. Infants who do not demonstrate these early nonverbal communicative abilities and receptive language skills are at risk of having ASD and should be referred for an evaluation. Very young children with DLD may exhibit an understanding of a limited vocabulary and follow a few simple directions. Additionally, TD, DLD, and infants later diagnosed as LT will pair vocalizations with their nonverbal means of communication whereas infants with ASD, who may demonstrate a form of nonverbal communication, are unlikely to do so (Schoen et al., 2011).

Infants may attempt to produce words with meaning between nine and fourteen-months of age. This is not typically observed in infants who are later diagnosed with ASD or DLD. However, up to 10% of all toddlers have not yet begun using meaningful words by the time they reach their second birthday. Population studies indicate that only a small percentage of children who demonstrate a language delay have ASD. The incidence of late talking is about one in nine or ten children in the general population. The overwhelming majority of children with ASD are late talking. However, most children who talk late do not have ASD (Camarata, 2014b).

Both infants and toddlers of monolingual and bilingual parents later identified as having ASD may exhibit intact phonological development for expressive language (Armon-Lotem & Meir, 2022). It is important to note that a smaller portion of these toddlers will demonstrate superior or above average production of sounds and words within the appropriate age range (Schoen et al., 2011). However, the words and phrases are often repeated right after they are heard and produced in the form of immediate echolalia absent of meaning or intent. Pediatricians must not rely solely on the infants’ production of words, but also the context in which those words are used along with the infants’ overall abilities in all areas of early language and communication development.

Infants at approximately 18-months old will begin engaging in pretend play, e.g., pretending to feed a baby doll, parking a toy car in a garage, etc. Infants with ASD at this age do not typically demonstrate behaviors associated with pretend play. If they do manipulate their toys they tend to do so in a rigid and restrictive manner, such as lining up toy cars, or engaging in stereotypic behaviors with the toys. Infants who are not yet producing words but are demonstrating appropriate pretend play may later be identified as having DLD as opposed to ASD.

There is a strong inter-relationship that exists between receptive and expressive language in TD toddlers. Toddlers identified later with ASD often exhibit dissociations between receptive and expressive language and present with significant deficits in both (Camarata, 2014a). They often demonstrate a limited ability to learn observationally which involves acquiring skills and responses by observing others engage in them without having to be taught directly (Taylor et al., 2012). In contrast, infants and toddlers later diagnosed as having DLD generally present with age-appropriate receptive language skills, such as knowledge and understanding of vocabulary, following simple directions, and engaging in observational learning.

There are a few commonalities that may be observed in toddlers who are later identified with either ASD or DLD in addition to the lack of expressive language. Both groups may be visual-spatial-analytical learners. They may be proficient or advanced at completing puzzles and stacking blocks in size order. They are also likely to be slower to toilet-train than their TD or LT peers, but this similarity is observed later than infancy (Camarata, 2014b).

Summary and Recommendations

Advances have been made in diagnosing young children with ASD much earlier than three-years of age. As stated above, the American Academy of Pediatrics (Hyman et al., 2020) recommends that all toddlers be screened for ASD between 18 and 24 months of age. However, the absence of developmental nonverbal communication skills and receptive language may be observed prior to an infant’s first birthday, signaling a risk for ASD, or possibly DLD. Once physiological causes, such as hearing and/or vision loss are ruled out, pediatricians, in consultation with the infants’ parents, should make a referral for an evaluation by a multidisciplinary team with expertise in ASD earlier than 18 months of age. This will enable early intervention services, if necessary, to begin sooner than in previous years.

The increased intervention these toddlers require necessitates that the clinical team be educated and trained in evidence-based treatments and teaching strategies based on the science of applied behavior analysis (ABA). This is particularly important regarding the speech-language pathologist (SLP) on the team since the early deficits involve communication and language. The team must also include a behavior analyst, psychologist, and special education teacher. A toddler or preschooler who is later identified as having DLD may only require treatment intervention from an SLP and a special education teacher. Other related service providers may serve on their clinical team depending on the toddlers’ or preschoolers’ needs (Paul et al., 2008). Infants who present with neurotypical developmental nonverbal communication skills and receptive language but do not later demonstrate age-appropriate expressive language, may be identified as late talkers.

Pediatricians and parents are key to initiating this process before the infants are twelve months old so that appropriate referrals may be recommended well before the age of two. It is important to remember that TD infants and those later diagnosed LT as toddlers or preschoolers will both demonstrate the early nonverbal communication and receptive language skills; infants with ASD will not. Pediatricians must be highly observant during regularly scheduled examinations and ask parents and caregivers instructive questions to gather the necessary information. In addition, it would behoove pediatricians to create a parent checklist that specifically targets the early nonverbal communication and receptive language deficits and characteristics of ASD if they do not currently have one. Information from parents is critical to obtain an overall picture of the infants’ functioning. Toddlers should not be diagnosed with this disorder based solely on their verbal abilities (Camarata, 2014b). ASD is a condition presenting with severe symptoms above and beyond talking late as indicated in this article and can be diagnosed prior to the anticipated development of speech.

References

American Academy of Pediatrics and American Speech-Language-Hearing Association. (2017). 7 Myths and facts about bilingual children learning language. Healthychildren.org. https://www.healthychildren.org/English/ages-stages/gradeschool/school/Pages/7-Myths-Facts-Bilingual-Children-Learning-Language.aspx

American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed.).

Armon-Lotem, S., & Meir, N. (2022). The differential impact of age of onset of bilingualism and language exposure for bilingual children with DLD and ASD. Linguistic Approaches to Bilingualism, 12, 33–38. https://doi.org/10.1075/lab.21055.arm

Bishop, D. V. M., Snowling, M. J., Thompson, P. A., Greenhalgh, T., & The CATALISE Consortium (2016). CATALISE: A multinational and multidisciplinary Delphi consensus study. Identifying language impairments in children. PLoS ONE, 11, e0158753. https://doi.org/10.1371/journal.pone.0158753

Byers-Heinlein, K., & Lew-Williams, C. (2013). Bilingualism in the early years: What the science says. LEARNing Landscapes, 7, 95–112.

Camarata, S. (2014a). Early identification and early intervention in autism spectrum disorders: Accurate and effective? International journal of speech-language pathology, 16(1), 1–10. https://doi.org/10.3109/17549507.2013.858773

Camarata, S. (2014b). Late-talking children: A symptom or a stage? https://doi.org/10.7551/mitpress/10035.001.0001

Centers for Disease Control and Prevention. (2023, April 4). Data & statistics on autism spectrum disorder. Autism Spectrum Disorder (ASD). https://www.cdc.gov/ncbddd/autism/data.html

Crais, E. R., Watson, L. R., & Baranek, G. T. (2008). Use of gesture development in profiling children’s prelinguistic communication skills. American Journal of Speech-language Pathology, 18(1), 95–108. https://doi.org/10.1044/1058-0360(2008/07-0041)

Gangi, D. N., Ibanez, L. V., & Messinger, D. S. (2013). Joint attention initiation with and without positive affect: Risk group differences and associations with ASD symptoms. Journal of Autism and Developmental Disorders, 44(6), 1414–1424. https://doi.org/10.1007/s10803-013-2002-9

Garrido, D., López, B., & Carballo, G. (2021). Bilingualism and language in children with autistic spectrum disorder: A systematic review. Bilingüismo y lenguaje en niños contrastorno del espectro autista: Una revisión sistemática. Neurologia (Barcelona Spain), S0213-4853(21)00077-3. Advance online publication.

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Patten, E., Belardi, K., Baranek, G.T., et al (2014). Vocal patterns in infants with Autism Spectrum Disorder: Canonical babbling status and vocalization frequency. Journal of Autism and Developmental Disorders, 44, 2413–2428.

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Schoen, E., Paul, R., & Schoen, K. C. (2011). Phonology and vocal behavior in toddlers with autism spectrum disorders. Autism Research: Official Journal of the International Society for Autism Research, 4(3), 177–188. https://doi.org/10.1002/aur.183

Taylor, B. A., DeQuinzio, J. A., & and Stine, J. (2012). Increasing observational learning of children with autism: A preliminary analysis. Journal of Applied Behavior Analysis, 45(4), 815–820. https://doi.org/10.1901/jaba.2012.45-815

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Yankowitz, L. D., Petrulla, S. P., Tunic, B., et al, (2022). Infants later diagnosed with autism have lower canonical babbling ratios in the first year of life. Molecular Autism, 13(1), 28. https://doi.org/10.1186/s13229-022-00503-8

Citation for this article:

Downey, J. M., & Mawby, I. (2023). Clinical Corner: Assisting pediatricians to recognize deficits in their infants and toddlers that may indicate a diagnosis of ASD. Science in Autism Treatment, 20(7).

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