Autism Spectrum Disorders PDF Print E-mail

Authored by MCN Neurologists

Definition

Autism is a term referring to a group of neurodevelopmental disorders manifesting in a broad spectrum of behaviors, varying widely in severity and outcome.  This disorder is classified diagnostically within the pervasive developmental disorders (PDDs), according to the American Psychiatric Association Diagnostic and Statistical Manual of Mental Disorders (DSM - IV).

The triad of 1) impaired sociability, 2) impaired verbal and nonverbal communication skills, and 3) restricted activities and interests at early onset are diagnostic of the autistic spectrum disorders.

The presence or absence of social disabilities distinguishes developmental language disorders from autism spectrum disorder.  Intelligence quotient, language, and social normalcy also distinguish non-autistic mental retardation from developmental learning disorders and autism spectrum disorder.

There is as much homogeneity (similarity) in the disorder as there is heterogeneity (variability), at times making very difficult the diagnosis and treatment for individuals with these disorders. 

The range of disabilities is quite considerable.

Asperger's syndrome represents the high-functioning end of the autism spectrum disorders. In that syndrome, paralinguistic difficulties (non-verbal) are noted rather than linguistic problems.

Specific Clinical Features - Symptoms

The presence of language and social deficits defines autism spectrum disorder.

Intelligence and Cognition

Some experts consider that the core cognitive deficit of autism spectrum disorder may be an inability to grasp other people's thoughts or a failure to develop a "theory of mind".

Others have suggested it may have to do more with abnormalities of executive functioning or the inability to problem solve, shift sets and plan to reach goals.  Another theory postulates difficulties with a central coherence, or the capacity to integrate information and see the whole.

Language

A main feature of autism spectrum disorder is verbal and nonverbal communication difficulties.  There is a range of language skills related to functional level.  There are deficits, however, in the pragmatics of language and prosody (the patterns of stress and intonation used in language).  There may be difficulty in both initiation of a conversation and comprehension, as well as the development of appropriate responses.  There may be preference to engaging well-rehearsed topics and perseveration (repetition of words).  Poorly modulated speech may be noted.  Some children and adults may be literal and concrete.  It is thought that language skills at age five or six years may predict long-term prognosis for most patients.  Overall, it is felt that children with conversational language will do better than children who have little or no language.

Social Skills

Social dysfunction is a core feature of the autism spectrum disorder; however, there is also some variability within the group.  Some observers note that passive children may, generally, have somewhat higher functioning, but still they do not make social approaches; however, will accept them when made by others.

There is a restricted range of behaviors, interests and activities. There may be repetitive stereotyped behaviors, such as twirling, rocking, flapping, licking, opening and closing doors, etc.  Difficulties with social situations may be the setting for such stereotypes.  Abnormal sensory reactivity may be noted.  These features may be the underpinnings of some of the self-stimulatory stereotypes and behaviors.  There may be some overlap with tic disorders and obsessive/compulsive disorders, which are mostly noted in the higher functioning children.

Difficulties with transition are also noted. There may be over-focusing on some activities and inattentiveness to others. Some youngsters and adults may have exceptional abilities, for example, in art, music or mathematical areas.

Comorbid Features

Tic (movement) disorder, nonverbal learning disabilities, attention deficit disorder (with or without hyperactivity) and/or obsessive-compulsive disorder are often seen along with the autism spectrum disorder. These at times are the features first noted in the child.

Seizures

Approximately one-third of youngsters with the autism spectrum disorder diagnosis develop a seizure disorder.  It is felt that the onset of seizures or mood disorders, especially depression, can cause a decline in performance by the adolescent years.

Psychiatric Difficulties

Mood disorders may present at any time, but perhaps more so in adolescence. Careful screening, evaluation and support enhance function and well being for the patient and the family.

Evaluation at the Neurologist's Visit - What to Expect?

Careful evaluation of past medical history, including prenatal and perinatal factors, is important.  Family history is a part of this consultation as well.  The neurologic exam is usually grossly within normal limits.  The physical exam is undertaken with careful review of the skin, head size, cranial nerve exam, fine motor and gross motor exams, sensory exam and coordination.  A formal audiologic (hearing) evaluation is important in the assessments of youngsters with autism spectrum disorder.

Tests to be considered may include genetic and metabolic workup laboratory studies, although these depend on the clinical situation.  Brain imaging is also to be considered, to assess for the presence of any central nervous system difference, which may correlate with the neurodevelopmental disorder.  Some authors have suggested that an MRI may show abnormalities in one-third of patients, particularly when the neurologic examination is abnormal.  On occasion, an electroencephalogram (EEG), a recording of the brain's electrical activity measured on the scalp, will be suggested to exclude sub-clinical seizures.  This may be particularly important when language impairment is prominent.  It is also considered when there may be prolonged episodes of staring.  Important to note, is the fact that an abnormal EEG does not make the diagnosis of epilepsy. Epilepsy remains a clinical diagnosis, that is, from clinical observation.  The EEG helps correlate the concerning behaviors with the electrical brain wave signature.

Treatment

Early intervention provides the best opportunity for mitigating developmental abnormalities in autism spectrum disorder.  Toddlers and pre-school children with the diagnosis of autism spectrum disorder should receive special education services within a therapeutic behavioral modification program.  In youngsters with Asperger's syndrome, the therapies are often focused around the use of social groups.

Medication treatment may be necessary and can be very helpful.  Medications used for autism are to be considered when difficulties with hyperactivity and inattention, obsessive/compulsive behaviors, mood difficulties with issues regarding aggressiveness and impulsivity, tic or stereotypes, self-mutilation, psychosis, seizures or sleep problems are noted.  Each of the different areas of difficulty has a group of possible medication choices.  The parent and physician review, in detail, which are the more disabling areas to try to address with medication, then medication choices are selected based on those with the most benefit and the least, or preferably no, side effect potential for the child.

Adults with Autism Spectrum Disorder

These patients will continue to need support and encouragement through their adult lives.  Many of the high functioning adults with autism spectrum disorder, especially Asperger's syndrome, are able to work successfully in regular mainstream jobs.  However, there may be communication and social difficulties that require some understanding in order to help the person remain employed. Many patients may require some supervision in the job setting.  It should be noted that the public school's responsibility for services ends when the person with autism spectrum disorder reaches the age of 22.  The person's family is then challenged with finding living arrangements and employment. Efforts to match the individual with the safest, most appropriate situation regarding housing and employment are very important.  Many of the best programs for adults with autism spectrum disorder have been created by family advocates.

Outcomes

Acceptance is the key in the evaluation and treatment of individuals with autism spectrum disorder. The challenges are many.  The health care provider's role and responsibilities are to understand the disorder with its varying manifestations and to help guide the patient and the family, as best possible, through the vast array of therapies, with ongoing support, compassion and dignity.

 

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Please consult your neurologist for information specific to your circumstance.