EARLY INTERVENTION MAY REDUCE THE SEVERITY OF AUTISM
Writer’s comment: I first became interested in autism the summer after my freshman year of high school when I was a volunteer teacher’s aide. I was assigned a class of severely handicapped children, and the student I found most interesting was an autistic 11-year-old boy. At the time, he did not speak and was treated as intellectually “slow.” Since then, treatment advances have enabled this young man to integrate into regular high school classes with an aide who “facilitates” his communication through a laptop computer. The best part of writing my paper for English 102 (Writing in the Health Sciences) was contacting the young man’s mother, whom I had never met, and listening to her story of raising Jason and his three brothers. It reinforced my observation that first summer that the disabled are people first, people with whom we have a great deal more in common than we have differences.
- Carolyn Lex
Instructor’s comment: Carolyn wrote this paper for English 102: Writing in the Health Sciences. It is a feature article like you find in the Tuesday “Science Times” of the New York Times.Notice that she cites her sources the way that journalists do, naming them in the article as though she both read their work and talked with them (but, because she is a student, she also includes a nonjournalistic reference list). It seems to me that Carolyn has risen to the difficult challenge of addressing an educated audience of both critical scientists and non-scientists reading for interest—her article is people-oriented, follows an enticing and engaging structure, and provides new, clear, fascinating detail on a significant topic. If I found it in the New York Timesone Tuesday morning, I would keep reading right through breakfast.
- Susan Palo, English Department
Scientists are gaining a new understanding of how the brains of autistic individuals work. Their discoveries have led many to believe that early intervention may reduce the severity of the disorder.
The brain continues to develop after birth. Therefore, early damage can often be compensated for if another part of the brain takes over the responsibilities of the damaged area. Because the brain’s ability to reorganize itself declines rapidly during the first few years of life, techniques that allow for early detection of autism are critical. Several such diagnostic methods have recently been proposed. Most of these are based on the analysis of videotapes of infants later diagnosed with autism.
Autism is a developmental disorder that affects the functions of the brain. Individuals with autism most often have serious problems with social interaction and with communication and imagination, as well as unusual behavior patterns (rituals, preoccupations, and repetitive behaviors).
Dr. Philip Teitelbaum and his colleagues at the University of Florida in Gainesville were able to detect reliable differences in the movements of autistic infants at 4-6 months of age. The way these children learn to roll over and later to walk is not the same as the way of normally developing children. Overall, the movements of autistic children are less coordinated. For example, when sitting, they distribute their weight unevenly, causing them to fall over. Results from his study led Teitelbaum to conclude that “movement disturbances play an intrinsic part in the phenomenon of autism… and can be used to diagnose the presence of autism in the first few months of life.”
According to Teitelbaum, most infants learn to turn over around three months of age. They accomplish this task by rotating their body in a corkscrew fashion. The pelvis moves first, followed by the trunk and finally the shoulders and head. This order is reversed around 6 months, when the roll is initiated with the turning of the head.
The autistic babies in the videos did not follow either of these patterns. Some were completely unable to turn over. The rest, Teitelbaum describes, “arch themselves sideways by raising the head and pelvis upward. This narrows the base of the body so that by moving the upper leg forward that leg can serve as a weight to topple the body over. All of the segments of the body move en bloc,not in a corkscrew fashion. This results in the child falling over, without any active rotation.”
In terms of walking, according to Teitelbaum, normal children, learning to walk for the first time, always progress through a series of stages. The earliest form of walking is called the “waddling walk.” This name comes from the way the baby waddles from side to side with each step. The next stage involves a more coordinated movement of the legs, but the child does not shift its weight until both feet are planted firmly on the ground. The final stage is characterized by the synchronization of the moving legs with the transfer of weight. Teitelbaum’s videotapes revealed that autistic children proceed more slowly though these stages, occasionally becoming stagnated at a certain stage. For example, a three-year-old boy was found to still use the “waddle walk” with his right leg, while his other leg moved in a more “mature” style. Another five-year-old boy showed age appropriate movement, but the shift of weight did not occur until both feet were back on the ground.
At the University of Washington, a second pair of researchers, Dr. Julie Osterling, and Dr. Geraldine Dawson, also used videotape analysis to look for distinguishing behaviors of autistic children. They focused on early social behaviors including pointing, looking at others, and orienting to name in videos of the children’s first birthday. Like Teitelbaum, they also found differences between autistic and normally developing children: “The development of the children with autism seemed to be arrested in the earlier sensorimotor stages while the control children continued to progress at a normal rate.” Most significant was how little time the autistic children spent looking at others.
To experts, the results of these studies are promising. Although the sample size in both experiments was small, the detection techniques used were highly reliable. Evaluators blind to the child’s diagnosis correctly identified 95% of the autistic children. The earlier these children are identified, the sooner they can receive treatment and the more likely it is that their condition will improve.
Parents of autistic children often notice abnormalities in the behaviors of their children in the first few months of life. One mother recalls the first time she knew something was wrong with her son: “I noticed that Jason seemed distant starting when he was about 6 months old, but the doctor assured me that he would grow out of it.” The clinical diagnosis of autism is currently based on social interactions that are not observed at such a young age. Because most children are not diagnosed until they are around 3 years old, treatment does not start until this time.
While the causes of autism are still unknown, evidence from recent research supports the hypothesis of prenatal brain damage. The cause of this damage is unknown, although leading scientists have suggested an intrauterine virus, chromosomal abnormalities, or metabolic disorders as possibilities.
Whatever the cause, these experts say, the results appear to be an incomplete or defective development of the cerebellum and brainstem. Both of these structures have extensive connections with other parts of the brain, especially in what is known as the limbic system.
The limbic system, a group of structures located toward the inside of the brain, is important for its role in motivation, behavior, emotion, and arousal, all of which are known to be affected by autism. According to Dr. Stephen Edelson from the Center for the Study of Autism, “The correspondence between behaviors seen in autism and what we know of the limbic system is compelling.” Researchers right now, however, know very little about the contribution of the limbic system to autism.
The cerebellum is responsible for the coordination of movement. An incomplete or defective development could account for the differences Teitelbaum detected in motor development.
Dr. Eric Courchesne at the University of California at San Diego has studied the role of the cerebellum in controlling attention. He suggests that “these attention . . . deficits may in part underlie the failure of autistic babies to engage in normal joint social attention and their failure to develop normal social communication skills.”
The children Courchesne studied at Children’s Hospital in San Diego were especially impaired in the ability to shift their attention. A normal infant, Courchesne explains, “shifts his or her focus of attention to follow the rapidly changing verbal, gestural, postural, tactile, and facial cues that signal changes in the stream of social and nonsocial information.” Furthermore, he adds “[They] use behavioral cues (gestural, postural, and so forth) to direct shifts of attention in the mother during such joint interchanges.” In contrast, autistic babies, Courchesne explains, “enter the world unable to smoothly and selectively shift their mental ‘spotlight’ of attention.”
The cerebellum also modulates the brainstem’s response to sensory stimulation. It follows that the baby would be unable to respond appropriately to sensory stimuli. This impairment leads some autistic infants to avoid all forms of stimulation, while others may engage in self-stimulatory behaviors such as head banging.
Luckily, early intervention may help alleviate some of these behaviors. Cindy Hatch-Rasmussen from the Center for the Study of Autism is experienced with using sensory integration therapy to help autistic children. Sensory integration takes advantage of the ability of the infant brain to reorganize itself by forming new connections. If other parts of the brain can be stimulated to take over the responsibilities of the damaged structures, these children may be able to function normally. This therapy focuses on three areas of sensory stimulation: tactile (touch), vestibular (balance), and proprioceptive (an awareness of one’s physical self).
Tactile stimulation comes from the sense of touch. Autistic children can be over or under reactive to touch. According to Rasmussen, an oversensitivity to touch can lead to “excessive brain activity, which can neither be turned off nor organized. This type of over stimulation in the brain can make it difficult for an individual to organize one’s behaviors and concentrate.”
The vestibular system is comprised of the organs of the inner ear and is responsible for our perception of motion and our awareness of our position in space. Hypersensitive children may attempt to avoid vestibular stimulation and become afraid of things like elevators. Conversely, hyposensitive children will attempt to stimulate their vestibular system with actions like spinning and jumping.
Finally, the proprioceptive system is the system of muscles and joints responsible for the way we hold our bodies (i.e., posture) and the way we move. Signs of proprioceptive problems, Rasmussen reports, include “clumsiness, a tendency to fall, a lack of awareness of body position in space, odd body posturing, minimal crawling when young, difficulty manipulating small objects (buttons, snaps), eating in a sloppy manner, and resistance to new motor movement activities.”
Sensory integration therapy is based on the idea that exposure to a variety of sensory stimuli stimulate the brain to organize itself in a way that allows this information to be meaningfully processed. This constitutes a reorganization of the central nervous system that can compensate for the areas that are damaged. With Rasmussen’s help, the children receiving sensory integration therapy are also assisted in “learning to inhibit or modulate sensory information and in processing a more organized response to sensory stimuli.” If this sort of therapy is started early enough, experts believe that it will be effective in decreasing the severity of the symptoms of autism.
Courchesne, E., J. Townsend, and O. Saitoh. (1996). The brain in infantile autism: Posterior fossa structures are abnormal. Neurology, 2, 84-92.
Edelson, S. (1999). Autism and the limbic system. In Center for the Study of Autism.[Online] Available: http://www.autism.org/limbic.html [1999, March 7]
Hashimoto, T., M. Tayama, K. Murakawa, and T. Yoshimoto. (1995). Development of the brainstem and cerebellum in autistic patients. Journal of Autism and Developmental Disorders,1, 1-18.
Lex, Carolyn. (February 1, 1999). Interview with a mother of an autistic child.
Osterling, J., and G. Dawson. (1994). Early recognition of children with autism: A study of first birthday home videotapes. Journal of Autism and Developmental Disorders,24, 247-258.
Rasmussen, C. (1999). Sensory Integration. In Center for the Study of Autism.[Online]. Available: http://www.autism.org/si.html [1999, March 8]
Teitelbaum, P., O. Teitelbaum, J. Nye, J. Fryman, and R. Maurer. (1968, November 18). Movement analysis in infancy may be useful for early diagnosis of autism. PNAS [Online]. Available: http://www.pnas.org/cgi/content/full/95/23/13982 [1999, March 7].