Autism Diagnosis and Developmental Milestones - אבחון אוטיזם ואבני דרך התפתחותיות
- motim51
- Jul 16
- 7 min read
A formal autism diagnosis is typically made around the age of two to three years. However, the first red flags and parental concerns often emerge during the first year of life, particularly in areas such as language and social communication.
Since there are currently no biological markers for diagnosing autism, and the diagnosis is based solely on clinical and descriptive criteria, the early identification of patterns in the acquisition of developmental milestones is critical for taking advantage of the therapeutic window of opportunity.
In other words, if parents and developmental professionals know which developmental patterns may indicate an increased likelihood of an autism diagnosis, they will be better able to refer the child for an early assessment and, consequently, early intervention.
Early intervention is highly valuable for two main reasons:
First, due to brain plasticity, the younger the toddler is, the greater the potential for neurophysiological changes in the brain, and the more significantly the child’s future functional prognosis may improve. An example of this can be found in data from the Koegel Autism Center, whose researchers developed Pivotal Response Treatment (PRT). Approximately 95% of children who received PRT before the age of three developed spoken language. In contrast, this percentage drops to approximately 20% among children who began treatment after the age of five.
Second, the earlier a toddler receives appropriate support, the earlier they can learn to communicate in an adaptive and effective way within their social environment. For example, when the child is in pain, they may learn to communicate this to an adult and receive help, rather than responding by crying or having an outburst. The earlier intervention begins, the greater the likelihood that the child will acquire effective adaptive behaviors.
Several studies in the professional literature have examined the early identification of autism through developmental milestones and have reached interesting conclusions. These findings may help both parents and professionals identify red flags and, consequently, refer children to the appropriate professionals in order to receive support at an earlier age.
The Developmental Milestones Study in Portugal
A recently published study examined 127 children from Porto, Portugal, with an autism diagnosis and a mean age of 34 months. The study assessed six developmental milestones that parents can recall relatively reliably:
Social smiling
Sitting steadily without support
Independent walking
First words
First word combinations or sentences
Daytime toilet training or daytime bladder and bowel control
A delay was defined as acquiring a milestone at or above the 95th percentile compared with normative developmental data, or as not having acquired the milestone at all by the time of data collection.
Language regression was also assessed and was defined as the consistent loss of at least five words for a period of at least three months.
The data presented in the article reveal a clear dichotomy between early motor development and communication and adaptive functioning:
Sitting: Most children acquired independent sitting on time, with only 2.5% showing a delay.
Social smiling: Social smiling was acquired on time by 79.5% of the children, while 20.5% showed a delay.
Independent walking: This milestone showed a more substantial delay, with 38.6% of the children experiencing delayed acquisition of independent walking.
Communication, language, and daily living skills: The most pronounced differences from the general population were found in these areas:
62.6% experienced a delay in producing their first words, and 11.1% did not speak at all.
96.8% experienced a delay in producing their first sentences, while 73% of the entire sample had not acquired this milestone at all by the time of assessment.
85.2% experienced a delay in achieving daytime bladder and bowel control, and 64.8% had not achieved daytime continence at all.
Language regression: Language regression was identified in 11% of the children, at a mean age of approximately 20 months.
The Motor Milestones Study in Israel
In the context of motor development, a large-scale Israeli study conducted at the Child Development Center at Sheba Medical Center, Tel Hashomer, by Prof. Lidia Gabis and her team sheds new light on the close association between early motor delay and a later autism diagnosis.
The study was based on a retrospective analysis of the medical records of 467 children diagnosed with autism.
The sample included 356 boys (76%) and 111 girls (24%), a gender ratio that approximately reflects the distribution of autism diagnoses in the general population. The children were diagnosed at a mean age of 3.4 years. Approximately 20% of the children in the sample were born prematurely and received routine follow-up care at a preterm infant clinic.
The study found that most children diagnosed with autism did acquire their motor skills within the broad limits of the normative range. However, the researchers identified a significant tendency toward the later end of that range.
Consistent with the findings of the Portuguese study, independent walking provides an excellent example of this pattern. Although walking by 18 months of age is considered medically within the typical range, most typically developing children begin walking before 16 months. In this study, the mean age of walking among children diagnosed with autism was later than usual: approximately 16 months for boys and nearly 18 months, specifically 17.9 months, for girls.
Another notable finding of the study was the gender difference.
Motor delay was identified in 60% of the girls diagnosed with autism, compared with only 47% of the boys.
Approximately half of the entire sample experienced global developmental delay, defined as a significant delay in two or more developmental domains. The gender difference was also evident in this area: 49% of the girls showed global developmental delay, compared with 36% of the boys.
The researchers explain that autistic girls often display early social and communication abilities that may mask their difficulties during the early stages of development. As a result, they are more likely to be missed by standard screening tools. Therefore, the presence of motor delay, particularly delayed independent walking, constitutes a critical red flag in girls and should prompt an immediate comprehensive communication assessment.
Among the subgroup of children born prematurely, who comprised approximately 20% of the sample, both the severity and prevalence of motor and global developmental delays were even greater. Within this group, the delay was especially pronounced among girls born prematurely, who showed the latest mean age of independent walking, at 18.79 months.
Comorbidities
The highest prevalence of comorbid conditions was found in the area of sensory regulation.
A total of 92.9% of the children were diagnosed with sensory processing disorder (SPD), primarily involving the vestibular system, which is located in the inner ear and is responsible, among other functions, for balance, and the tactile system, which relates to touch. In addition, sleep disorders were reported in 18.1% of the children, hypotonia in 7.1%, and epilepsy in 3.1%. A total of 15.7% of the children had a family history of autism in a first- or second-degree relative.
Predictive Value of the Different Developmental Milestones:
Daytime bladder and bowel control: This milestone had the broadest predictive effect. The researchers emphasize that a delay in achieving daytime continence serves as a strong indicator of lower overall intellectual abilities.
Social smiling: A delay in social smiling was directly and significantly associated with a lower score on the personal-social scale at a later stage.
Language (words and sentences_: Delays in producing first words and first sentences significantly predicted lower scores on the personal-social scale, which assesses daily living skills, social learning, and interactions with peers.
Independent walking: A delay in walking did not affect language abilities but was significantly associated with poorer performance in nonverbal cognitive skills.
Key Clinical Insights from the Scientific Literature
The early motor profile: Unlike language and social communication, gross motor milestones during the first year of life, such as sitting, generally remain within the typical range among autistic children. However, independent walking tends to be delayed and may serve as an early indicator of later difficulties in nonverbal cognitive functioning.
Motor delay as a gender-related red flag, particularly in girls: The findings of Prof. Gabis and colleagues emphasize that motor delay and global developmental delay are significantly more common among autistic girls than among autistic boys. Motor delay was identified in 60% of the girls, compared with 47% of the boys.
Because girls often display social abilities that may mask their communication difficulties, delayed independent walking, especially among girls born prematurely, should be regarded as a major red flag requiring immediate referral for a comprehensive communication assessment.
Preventing a diagnosis of global developmental delay alone: Children with combined motor and language delays are sometimes diagnosed with global developmental delay, with no further assessment conducted. Recognizing that motor delays may be an integral part of the physical presentation of autism is essential for preventing a missed autism diagnosis and enabling the child to receive communication-focused interventions at an early stage.
The predictive value of daytime continence: The study emphasizes that difficulty achieving daytime toilet training is not merely an isolated adaptive issue. Rather, it may serve as a powerful diagnostic indicator associated with the overall severity of cognitive, language, and social delays.
The importance of retrospective clinical documentation: Careful monitoring and accurate collection of developmental history regarding the ages at which milestones were acquired, particularly social smiling, language, and daytime continence, are essential for developing early, individualized, and goal-oriented intervention plans.
References:
Gabis, L. V., Attia, O. L., Roth-Hanania, R., & Foss-Feig, J. (2020). Motor delay-An early and more common" red flag" in girls rather than boys with autism spectrum disorder. Research in Developmental Disabilities, 104, 103702. https://doi.org/10.1016/j.ridd.2020.103702
Sousa, D., Queirós, J. C., Tavares, T., Soares, S., Matos, I. V., Prior, C., ... & Prior Sr, C. (2025). Early Neurodevelopmental Milestones in Children With Autism Spectrum Disorder: A Retrospective Observational Study. Cureus, 17(12). DOI: 10.7759/cureus.99042
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