Autism-like Behaviors

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  Autism-like Behaviors in Children with Down Syndrome

Autism-like behaviors are those behaviors commonly seen in children with Autism spectrum disorders (ASD). ASD is best defined as a neurobehavioral symptom-complex with three core features, 1) impairments in reciprocal-social interaction, 2) impairments in social-communication and 3) a relatively restricted and stereotyped pattern of behavioral interests and activities. As a neurobehavioral symptom-complex, ASD is a diagnosis based upon observed behaviors and not necessarily its cause or etiology. For the purpose of this discussion ASD is meant to include: infantile autism (onset prior to 3 years) and late-onset autism (onset after 3 years). These conditions are sometimes referred to as pervasive developmental disorders (PDD). ASD is a life-long condition for which there are treatments but no known cure. In children with DS+ASD the severity of autism-like behavior is often associated with the degree of intellectual and language impairment.

Does ASD occur more often in people with DS compared to the general population?

The prevalence of ASD in persons with DS is estimated to be between 5-7%, which is substantially higher than in the general population. The prevalence of autism-like behaviors (without ASD) is also higher. The presence of an extra copy of chromosome 21 affects brain development in such a way that it predisposes some children to develop atypically compared to most other children with DS. Although the specific reasons remain unknown, it would appear that certain neurobiological events during brain development-organization goes awry, resulting in a differently designed brain.
How is ASD diagnosed in children with DS? 
A diagnosis is usually made thru direct observation and by understanding a particular child’s developmental-behavioral trajectory over time. In order to establish the diagnosis of ASD each of the three "core-features" of ASD must be present to such a degree that it results in “functional impairment”. The lack of diagnostic tests specifically for children with intellectual disability may create considerable confusion for professionals, parents, educators and others trying to understand the child and provide for his/her therapies, education and care. 
The commonly agreed upon core features of ASD include: 
  • Impairment in relating to people in social circumstances (social-disinterest, poor eye-contact, anxiety, social avoidance or withdrawal)
  • Impairment in communication (initiating or understanding spoken words, signs and/or gestures; lack of imaginative play)
  • Repetitive body movements and/or a persistent pattern of repetitive or ritualistic behavior. A persons focus of these activities are usually intense.
Aversion to certain sensory stimuli, which is often observed in both DS or ASD, is NOT considered to be one of the core features of ASD. Repetitive motor movements and sensory aversions together, although impairing, are NOT the most important criteria for diagnosing ASD. Children who do not manifest all three of these core features at levels considered “significantly impairing”, but who have many of the essential qualities of ASD may not receive a diagnosis of ASD. 
What makes ASD a spectrum disorder?
There is variation in the degree of impairment among the three core features, resulting in a highly-individualized profile of symptoms which may be mild or severe.
Many symptoms of ASD overlap with other conditions such as obsessive-compulsive disorder (OCD) or stereotypy (repetitive) movement disorder.
ASD is a developmental diagnosis: the expression and manifestation of the syndrome varies with the age and the maturational level of the child.

Can autism-like behaviors be confused with other disorders?

Yes, diagnostic confusion is common for several reasons:
First, the diagnosis of ASD may be overlooked or thought by some professionals to be inappropriate for a child with DS and intellectual disability. Second, only certain aspects of the ASD symptom-complex may be recognized. For instance, if a child has a high degree of hyperactivity and impulsivity only a diagnosis of ADHD may be considered. Third, some of the same behaviors are seen in other childhood disorders which DO NOT QUALIFY for the diagnosis of ASD.

Frequently confused with ASD but DO NOT QUALIFY for an ASD diagnosis
Some children with repetitive motor behaviors, inattention and sensory dysfunction may appear to have ASD.

Children with ADHD, sensory dysfunction, and disruptive behaviors who are difficult to manage may appear to have ASD.
Some children with obsessive-compulsive features look similar to ASD (dependence upon routines, need for sameness, perseveration on certain fixed themes).
These conditions DO NOT QUALIFY for ASD when social and communication skills are relatively intact.

What signs would make you think that ASD is possible?  

Children in this group may display unusual or atypical behaviors during infancy or the toddler years.
Some of the behaviors often seen prior to 2-3 years of age include:

  • Repetitive motor behaviors (body rocking, excessive mouthing of objects or fingers, frequent hand or finger waving)
  • Light head banging or self hitting         
  • Fascination with and staring at lights or ceiling fans
  • Episodic deviation of eye gaze (seizures may be suspected)
  • Extreme food refusal (especially high textured foods)
  • Unusual play with toys and other objects (repetitive spinning, banging, waving)
  • Receptive language impairment (limited understanding of words or may act as if deaf)
  • Absent speech; and no interest in gestures or signs

LATER ONSET (> 3 years)
Another group of children are older when symptoms manifest.
Onset of symptoms may be slow and insidious occurring over many months or years; or sometimes there is a distinct developmental regression (loss of previously acquired skills between 3-6 years). Repetitive motor behaviors and sensory aversions may appear or intensify during this time. Some children are reported to have had subtle manifestations of staring, eye-deviation and repetitive behaviors prior to their regression, while others are said to have experienced “typical development” for DS.
Other behaviors commonly seen in this group include:

  • History of developmental regression (loss of speech, language, play or social skills)
  • Extreme irritability
  • Underactivity, apathy, loss of motivation and poor organization
  • Hyperactivity, short attention, impulsivity and poor organization
  • Unusual vocalizations (tongue-lip sucking, humming, grunting or other throaty noises)
  • Sensory aversions (to crowded rooms, sudden sounds or being touched)
  • Difficulty with changes in routine or when entering unfamiliar surroundings may result in extreme non-compliance, anxiety, fearfulness or agitation.
  • Sleep disturbance (frequent awakenings or decreased need for sleep)
  • Disruptive behaviors (yelling, throwing objects or physical aggression)
  • Self-injurious behavior (skin picking-scratching or biting, head hitting or banging)


Developmental regression is never normal and always indicates the need for further investigation. In some rare cases regression may be associated with abnormal EEG findings, thus an overnight or prolonged EEG study should be obtained if possible. In our experience however, the search for a specific medical cause for regression almost always proves elusive.

Who should make this diagnosis?

A concern about autism spectrum disorder or autistic-like behavior may first be mentioned by a parent, therapist, teacher or primary care physician. The diagnosis can usually be established by a developmental-behavioral pediatrician, child psychiatrist or child psychologist. More important than specific credentials, it is critical that the evaluator be experienced in assessing children with intellectual disability.

If a dual-diagnosis of ASD is suspected, what should a parent do?

Speak with your child’s primary care physician, and seek a referral to a knowledgeable professional who can help guide you. This may be a developmental or behavioral pediatrician with an interest in Down syndrome or autism, or a child psychiatrist or child psychologist at an academic medical center.If a diagnosis of ASD is confirmed you may wish to discuss possible treatment options with each of the different professionals you choose to consult. Be prepared for a sometimes dizzying and contradictory litany of suggestions. Work with professionals who will help you to understand, evaluate and prioritize your various options, and who are not overtly critical or threatened by your attempts to design a program that is best for your child.

What could someone expect from an evaluation process?

There is no consensus regarding the specific evaluations necessary to reliably identify ASD or the degree of functional impairment which must be present in order to establish the diagnosis of ASD.There is an Autism Diagnostic Observation Scale (ADOS); and several behaviorally–based checklists or rating forms which can be used with a high degree of confidence to support the diagnosis. A comprehensive evaluation should consist of taking a medical & developmental history; observation of the child in both structured and unstructured social or play settings; and a systematic rating of autistic behaviors according to one or more validated autism rating scales or checklists. Formal cognitive and language testing are often useful in helping to support the diagnosis of ASD. It is also important to determine if the child has an unidentified medical condition (clinical seizures, vision or hearing impairment)

Is it beneficial to have an official dual diagnosis of ASD?

Yes, because in almost all cases, ASD (not Down syndrome/intellectual disability) is the more functionally impairing developmental disorder. ASD in the setting of Intellectual disability needs to be a recognized dual diagnosis when creating a meaningful educational treatment plan. A diagnosis of ASD could entitle your child to more specialized educational and intervention services. In many communities such services can be extremely difficult to establish and implement with any sense of real cohesion. But it is an effort worth undertaking as earnestly and early as possible once a diagnosis of ASD is established.

What needs to be done differently if there is a dual diagnosis of autism-like behavior or ASD?
Contact your child’s school or intervention program to discuss changes to the IEP or IFSP. 

The most essential interventions for managing ASD in a preschool or younger school-aged child are:

  • Highly individualized (1:1) instruction utilizing an effective teaching method  (ABA-discrete-trial training or TEACH method)
  • A visually-based system of communication (simple picture exchange using photographs) when speech is absent or functionally inconsistent. Hold off on using an iPad language Apps until the child has developed some ability to use simple picture exchange, otherwise the iPad will be used for watching videos repeatedly
  • Behavior management to proactively reinforce desired behaviors and adaptive skills (requesting, toileting, feeding), and to assist in managing disruptive behaviors when present
  • Medication management to reduce target physiologic symptoms when present (sleep disturbance, irritability or anxiety, repetitive behaviors, hyperactivity, impulsivity, inattention or cognitive disorganization)
  • Sensory-based treatments designed to minimize hyper-responsiveness to environmental stimuli (avoid noxious sensory stimuli, provide a predictable, non-chaotic environment, use techniques to calm or relax your child)

Are there medications that can help with autism-like behaviors or ASD?

Perhaps. When deciding whether or not to attempt a medication trial parents should consider a number of factors such as: the severity and duration of symptoms, the degree to which physiologic symptoms or behaviors interfere with developmental, academic progress or social skill development, and their impact on family-social relationships. Also consider the direct impact of dangerous behaviors (aggression, self-injury) on the health and safety of the individual and caretakers. Even when medications are used, having a solid behavior management plan and functional communication strategy in place are essential to ensure the greatest chance for success. This often requires establishing a team of teachers, therapists and interventionist around the child in the school, home and community.

Optimizing treatment for DS+ASD

Because ASD is a long-term condition, for which there are treatments but no known cure, it is unclear if early diagnosis and prompt treatment results in an improved functional outcome for children with DS+ASD. One impediment to early treatment is that a proper diagnosis is often delayed until late in childhood, another is that some professionals are not comfortable using medications in preschoolers, or parents simply may not be interested in medications, opting to choose from a wide variety of other available therapies. It is often observed however, that children who respond favorably to medication for management of physiologic symptoms, are often better able to understand and benefit from educational, communication and behavioral interventions when implemented.

What are the possible long-term concerns with autism-like behaviors or ASD?
For the Child

  • May experience academic failure, or social isolation from peers
  • Placement in a more restrictive classroom setting
  • Risk of repeated physical injury to self or others
  • Difficulty with medical and dental procedures
  • Chronic, learned patterns of behavior may appear
  • Failure to respond to treatments, despite good faith attempts at behavioral, functional communication and medical interventions.
  • A psychiatric disorder, such as anxiety or mood-disorder, may yet appear
  • Adaptive skills (self-help, communication) may not develop to become functional
  • Their definition of happiness will be their very own
  • They will continue to delight and amaze you 

For the Caretaker

  • May become frustrated, sad, anxious, and sleep-deprived
  • Difficulty with community and vacation travel or special events
  • Increased out-of-pocket financial costs for care, supervision and therapies
  • Isolation from other families and friends and withdrawal from the DS community
  • Marital and family stress may result
  • You will develop a new appreciation for the mystery of the human condition and each person you encounter
  • You will learn to speak and think of your child as the person they are



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