Autism and Down Syndrome

Brain Development and Autism Spectrum Disorder

The development of the brain and how it functions is different in some ways in children with DS-ASD than it is in their peers with Down syndrome. Characterizing and recording these differences in brain development through detailed evaluation of both groups of children will provide a better understanding of the situation and will point to possible treatments for children with DS-ASD.

A detailed analysis of the brain performed at autopsy or with magnetic resonance imaging (MRI) in children with autism shows involvement of several different regions of the brain:

-- The limbic system, which is important for regulating emotional response, mood, and memory
-- The temporal lobes, which are important for hearing and normal processing of sounds
-- The cerebellum, which coordinates motor movements and some cognitive operations
-- The corpus callosum, which connects the two hemispheres of the cortex together

At Kennedy Krieger Institute, we have conducted MRI studies of 25 children with DS-ASD. The preliminary results support the notion that the cerebellum and corpus callosum are different in appearance in these children compared with those who have Down syndrome alone. We are presently evaluating other areas of the brain, including the limbic system and all major cortical subregions, to look for additional markers that will distinguish children with DS-ASD from their peers with Down syndrome alone.

Brain Chemistry and Autism Spectrum Disorder

The neurochemistry (chemistry of the brain) of autism is far from clear and very likely involves several different chemical systems of the brain. This information provides the basis for medication trials to affect the way the brain works in order to elicit a change in behavior.

An analysis of neurochemistry in children with ASD alone has consistently identified involvement of at least two systems.

-- Dopamine: regulates movement, posture, attention, and reward behaviors
-- Serotonin: regulates mood, aggression, sleep, and feeding behaviors

Additionally, opiates, which regulate mood, reward, responses to stress, and perception of pain, may also be involved in some children.

Detailed studies of brain chemistry in children with DS-ASD have not yet been done. However, our clinical experience in using medications that modulate dopamine, serotonin, or both systems has been favorable in some children with DS-ASD.

How Do I Find Out?

Obtaining an Evaluation

If you suspect that your child with Down syndrome has some of the characteristics of ASD or any other condition qualifying as a dual diagnosis, it is important for him to be seen by someone with sufficient experience evaluating cognitively impaired children -- ideally Down syndrome in particular. Some of the same symptoms that occur in DS-ASD are also seen in stereotypy movement disorder, major depression, post-traumatic stress disorder, acute adjustment reactions, obsessive--compulsive disorder, anxiety disorder, or when children are exposed to extremely stressful and chaotic events or environments.

Sometimes when children with Down syndrome are experiencing medical problems that are hidden -- such as earache, headache, toothache, sinusitis, gastritis, ulcer, pelvic pain, glaucoma, and so on -- the situation results in behaviors that may appear "autistic-like," such as self-injury, irritability, or aggressive behaviors. A comprehensive medical history and physical examination is mandatory to rule out other reasons for the behavior. When cooperation is elusive, sedation or anesthesia may be required. If so, use this "anesthesia time" effectively by scheduling as many specialty examinations as are feasible at one session.

In addition to the medical assessment, you will be asked to help complete a checklist to determine whether or not your child has ASD. I use the Autism Behavior Checklist (ABC), but there are others that are also used, such as the Childhood Autism Rating Scale (CARS) and the Gilliam Autism Rating Scale (GARS). Each of these is completed either in an interview with parents or done by parents before coming to the appointment. They are then scored and considered along with clinical observation to determine if your child has ASD.

Obstacles to Diagnosing DS-ASD

"If it looks like a duck, and it quacks like a duck... guess what?"

Parents sometimes face unnecessary obstacles in seeking help for their children. Parents have shared several reasons demonstrating this. Some of the more common include:

Problem: Failure to recognize the dual diagnosis

Result: Failure to recognize the dual diagnosis except in the most severe cases.

This is frustrating for everyone who is actively seeking solutions for a child. If you are in this situation and feel that your concerns are not being taken seriously, keep trying. The best advice is to trust your gut feeling about your child. Eventually you will find someone willing to look at all the possibilities with you.

Diagnostic Confusion

Problem: Diagnostic confusion with other behavioral or psychiatric conditions such as ADHD, OCD, or depression.

Result: Parents may feel forced into demanding a referral for another medical evaluation at a Down syndrome clinic or child-development center. Because of insurance factors, families can incur considerable costs if they take this route. Many HMOs and PPOs will not refer out or cover part of the cost for evaluations outside their system. The same is true for educational evaluations. Many school systems may be hesitant to provide additional, intensive, and costly services for kids with DS-ASD. The combination of frustration and lack of acceptance by professionals (medical and educational) of the dual diagnosis may lead parents to abandon traditional services in favor of nontraditional solutions to their child's medical and educational problems. This is not necessarily a bad thing. Individual, creative problem-solving is a great asset when support is elusive.

However, total withdrawal from "the system" may lead parents to feel abandoned and isolated, which makes it difficult for them to help their child and build the support systems they need to deal with stress. There will be plenty of frustrating and stressful moments in the future. Parents deserve support.

Lack of Acceptance by Professionals

Problem: Some professionals do not accept that ASD can coexist in a child with Down syndrome who has cognitive impairment. They may feel that an additional label is not necessary or accurate. Parents may be told, "This is part of 'low-functioning' Down syndrome." We now know this is incorrect. When standardized diagnostic assessment tools such as the ABC are used, children with DS-ASD are clearly distinguishable from children with Down syndrome alone or those who have Down syndrome and severe cognitive impairment.

Result: Parents become frustrated and may give up trying to obtain more specific medical treatment or behavioral intervention.

Confusion in Parents

Problem: Lack of acceptance, understanding, awareness, or agreement on the part of parents or other family members, particularly of very young children, about what's happening. Initial reactions by families and parents vary considerably, from "This too shall pass" to "Why isn't he doing as much as other kids with Down syndrome?"

Result: Parents in this situation may find themselves at odds with each other about the significance of their child's behavior and what to do about it. As a result, marriages are stressed, parenting relationships with other children are strained, and life is tough altogether. Unfortunately, I have found that parents in this situation almost universally withdraw from local Down syndrome support groups or other groups that may provide support. There are a variety of reasons for this, including "the topics discussed don't apply to my child," "It's just too hard to see all those children doing so much more than my child," and "I feel like people think I'm a bad parent because of my daughter's behavior."

Ideally, someone in the parent group would recognize this when it is happening and offer additional support instead of watching them withdraw. What is worrisome is that the very parents who are most in need of support and assistance cannot or do not receive it within the context of their local parent group. In fact, there may not be another parent in the group with a child who is similar, because DS-ASD is uncommon and not easily shared.

It is critical that parents have an opportunity to meet and learn from other parents whose children also have DS-ASD. Despite the underlying medical condition (trisomy 21), the neurobehavioral syndrome of ASD might mean that a support group for families of children with autism will be helpful as well. However, because of the lack of acceptance or knowledge about the dual diagnosis, these support groups can be equally daunting.

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