KNOWLEDGE AREA

^{HOW DO DOCTORS MAKE AN AUTISM DIAGNOSIS?}

^{By Lisa Jo Rudy}

Autism Spectrum Disorders (ASDs) should be diagnosed by a medical professional with support from physical, occupational and speech therapists. Ideally, everyone involved with a diagnosis should have significant experience with ASDs, their diagnosis and their treatment.

What does it mean to have an ASD? The new Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV) which defines all known medical disorders for the purposes of diagnosis, describes six characteristics of ASDs. To qualify for a diagnosis, a person must have a total of six or more items from (1), (2), and (3), with at least two from (1) and one each from (2) and (3):

1. Qualitative impairment in social interaction, manifest by at least two of the following:

· A. Marked impairment in the use of multiple nonverbal behaviors, such as eye-to-eye gaze, facial expression, body postures and gestures, to regulate social interaction

· B. Failure to develop peer relationships appropriate to developmental level

· C. Lack of spontaneous seeking to share enjoyment, interests, or achievements with other people (e.g., by lack of showing, bringing, or pointing out objects of interest)

· D. Lack of social or emotional reciprocity

2. Qualitative impairment in communication, as manifest by at least one of the following:

· A. Delay in, or total lack of, the development of spoken language (not accompanied by an attempt to compensate through alternative modes of communication such as gesture or mime)

· B. In individuals with adequate speech, marked impairment in the ability to initiate or sustain a conversation with others

· C. Stereotyped and repetitive use of language, or idiosyncratic language

· D. Lack of varied, spontaneous make-believe, or social imitative play appropriate to developmental level

3. Restrictive repetitive and stereotypic patterns of behavior, interests, and activities, as manifested by at least one of the following:

· A. Encompassing preoccupation with one or more stereotyped and restricted patterns of interest that is abnormal either in intensity or focus

· B. Apparently inflexible adherence to specific nonfunctional routines or rituals

· C. Stereotyped and repetitive motor mannerisms (e.g., hand or finger flapping or twisting, or complex whole-body movements)

· D. Persistent preoccupation with parts of objects.

Delays or abnormal functioning in at least one of the following areas, with onset prior to age 3 years:

· 1. Social interaction

· 2. Language as used in social communication

· 3. Symbolic or imaginative play

The disturbance is not better accounted for by Retts Disorder or childhood disintegrative disorder.

RECENT FINDINGS ON THE AUTISTIC BRAIN

Over the past few years, a number of studies have been published linking differences in brain structure and function to autism spectrum disorders. For example… scientists have noted that:

· At a certain point in post-natal development, autistic brains are larger.

· Testosterone may be linked to autism.

· Certain portions of the brain, such as the amygdala, may be enlarged in autistic brains.

· Certain parts of the brain may function differently in autistic people.

· "Minicolumns" in the brain may be formed differently and be more numerous in autistic brains.

· The entire brain may function differently in autistic people.

To better understand which of these findings is legitimate and which is most significant, I interviewed Dr. Nancy Minshew of the University of Pittsburgh. Minshew is one of the most prolific and best-known researchers in the field of autism and the brain. According to Dr. Minshew, "These different theories are not all so different."  

The Autistic Brain is "Differently Wired"  

What all of these brain findings have in common, Dr. Minshew explains, is that they point to autism as a disorder of the cortex. The cortex is the proverbial "gray matter": the part of the brain which is largely responsible for higher brain functions, including sensation, voluntary muscle movement, thought, reasoning, and memory.    In many autistic people, the brain develops too quickly beginning at about 12 months. By age ten, their brains are at a normal size, but "wired" atypically. "The brain is most complex thing on the planet," says Dr. Minshew. "So its wiring has to be very complex and intricate. With autism there's accelerated growth at the wrong time, and that creates havoc. The consequences, in terms of disturbing early development, include problems within the cortex and from the cortex to other regions of the cortex in ways that compromise language and reasoning abilities."

Minicolumns, which are small structures within the cortex, are also different among autistic people. Dr. Manuel Casanova, a researcher at the University of Kentucky, has found that autistic people have more minicolumns which include a greater number of smaller brain cells. In addition, the "insulation" between these minicolumns is not as effective as it is among typically developing people. The result may be that autistic people think and perceive differently and have less of an ability to block sensory input.

The Down Side of Unique Wiring

If autistic brains are wired differently across the board, is it a problem? Of course, for many people -- and in many ways -- the answer is "yes."  Says Dr. Minshew, "Autism really impacts behavioral function in the brain very broadly. It effects sensory, motor, memory, and postural control -- anything that requires a high degree of integration of information. The symptoms are most prominent in social interaction and problem solving because they require highest degree of interaction." In fact, she continues, "They're socially/emotionally far more delayed than anyone ever thought, even if they have a high IQ. Temple Grandin, a well-known speaker and writer with autism, says she's emotionally about 7 - 10 years old."

The Up Side of Unique Wiring

  While social and communication skills may be compromised by unique wiring in the brain, other abilities are actually enhanced. For example, says Dr. Minshew, "Autistic people have a really stellar ability to use the visual parts of the right side of the brain to compensate for problems with language processing. This may be the basis for detail-oriented processing -- and may be a decided advantage!" In fact, as she describes it, "Control children can't find Waldo. Autistic children can."