Autism is a collection of behavioural symptoms, not a specific disease. These symptoms are found in several specific medical conditions as well as the autism spectrum disorders. The terms Autism Spectrum Disorders and Pervasive Developmental Disorders refer to a group of disorders characterised by delays in the development of basic functions including socialisation and communication. This group of disorders includes
Asperger's disorder (Asperger's syndrome) and several other disorders in addition to autism.Although these diagnostic labels are used as if to indicate different disorders, it is possible that Asperger's disorder and Pervasive Developmental Disorder-Not Otherwise Specified are, in fact, mild forms of autism. Therefore, the terms "autism" and "autistic" are used to refer to the entire range of abnormalities that characterise this group of disorders.
Children who are autistic show impairments in three areas: socialisation; verbal and non-verbal communication; and a restricted range of activities and interests. Symptoms include:
Parents may be proud of their apparent self-sufficiency and independence, not recognising that these behaviours are abnormal.
The ability of young children with autism to understand and use speech and gestures for communication is usually impaired. As they grow older:
Those who do acquire speech may have difficulty holding a conversation with peers, and may have little vocal expression or an unusual rhythm.
Problems with non-verbal communication may reveal themselves as:
Young children with autism do not know how to play. They may
Children with autism often have difficulty with their attention span and activity level.
About 75% of children with autism are functionally mentally retarded, but IQ tests are of limited utility because some children in effective treatment programs make significant improvements. In general children with autism have:
A small number of children with autism, savants, may have exceptional talent in an area such as music, mathematics, or visuo-spatial perception despite deficits in other areas.
Young children with autism can have a variety of sensorimotor problems, including:
Some children are oblivious to sensory input. These will have a high tolerance of pain, and may seem to be deaf. Others will be overly sensitive and will dislike being touched, avoid certain textures of clothing or food, or cover their ears or panic when they hear specific sounds such as an aeroplane or a loud motor bike.
Many children with autism have scattered skills. They may:
Some researchers have reported that gastrointestinal disorders are more common in children with autism than in other children. Several problems have been reported to occur "frequently," including:
Why gastrointestinal disorders occur more frequently in children with autism than in other children has not been satisfactorily explained, but some researchers have described an "autistic enterocolitis" which may be related to the MMR vaccine.
Twenty years ago, autism was said to be a rare disease, occurring in 4 or 5 of every 10,000 children. Over the past twenty years, however, the number of children identified as having autism has increased dramatically, and many observers have said that there is now an 'epidemic' of autism. This has become a matter of controversy because some have attributed this apparent increase in the prevalence of autism to the presence of toxins in the environment or to the MMR vaccine.
The report of California's Department of Developmental Services, issued in 1999, is perhaps the most widely quoted source of data on the prevalence of autism. This report shows tremendous increases in the number of children with autism. Similar increases in numbers have been reported from other parts of the US and from Ireland and Britain.
However, the latest information from California reveals that while the number of children identified as autistic increased the number of children identified as being mentally retarded decreased.
As this is written (2 September 2002) it seems that several factors may have contributed to an apparent increase in the number of children with autism:
Putting several sources of information together, the prevalence of autism and related disorders could be as high as 91 per 10,000:
The cause of autism is not known, but it seems likely that some people have a genetic, or inherited, predisposition to autism, and that a second, unknown factor actually triggers the expression of the disorder. This factor probably exerts its effect during the first couple of months of pregnancy. Several conditions which have been said to cause autism are discussed here.
There seems little doubt that autism is a genetic disorder.
But, despite intensive study of several possible genes, none has been clearly identified as causative.
The suggestion that the measles component of the Measles Mumps Rubella vaccine (MMR) might cause autism was first made in 1993. It became a matter of controversy in 1998 when Dr. Andrew Wakefield, then a consultant at the Royal Free Hospital, London, published the first of a series of papers on the relationship between the measles vaccine and autism.
Dr. Wakefield's work has received enormous publicity in the press and on TV, and this has led to a polarised situation, both sides of which are presented here.
Dr. Wakefield's position can be summarised as follows:
Dr. Wakefield did not say that the measles component of the MMR vaccine caused autism. He did say that further research was indicated, and that parents should be given the choice of single vaccines rather than the 3-in-1 MMR.
His findings have been given a great deal of publicity and have been accepted by many parents of autistic children as sufficient evidence that the measles component of the MMR vaccine causes autism. As a result
The position of public health authorities is as follows
Parents, some of whom are scientists by profession, and their supporters believe that the public health authorities are less than candid, and quote as evidence of this
They also believe that
As a result of all this
Despite the present gloomy picture, there are some bright spots on the horizon:
The function of the gut, or intestinal tract, is to digest and absorb food, a process which requires that large molecules of foodstuffs be broken down to smaller molecules which are then absorbed through the very specialised lining of the intestine. This lining, the mucosa, also keeps out substances that should not be absorbed.
Proponents of the leaky gut idea suggest that if the intestinal mucosa is damaged, large molecules of foodstuffs, bacteria, and toxins may enter the body, causing food allergies, chemical sensitivity, and infections elsewhere in the body. Exactly how this then causes autism is not clear, but one possibility is a problem with the immune system. Another possibility is that some of these large peptides can act as opioids.
This idea has not been critically investigated.
Interestingly, it has been shown that children with autism sometimes have a bacterial species, Clostridia, growing in their gastrointestinal tract, whereas normal individuals do not. The significance of this finding is not known.
Several lines of evidence suggest that there might be an abnormality of the immune system in children with autism, but strong evidence is lacking:
This idea is slowly gaining acceptance among other immunologists, and further research is expected.
This idea holds that:
Proponents of this idea suggest that eating a gluten and casein free diet might then result in improvement. Several researchers have reported improvement with these diets, and the idea is worthy of further research. However, no controlled studies have been reported.
In human biology yeast means Candida albicans, a fungus which is normally found on the skin, in the mouth, in the intestinal tract, and in the vagina of healthy individuals. It is a part of the body's defense mechanism against unwelcome bacteria. Occasionally it causes minor infections of the skin and mucous membranes (e g. thrush in babies) in individuals who have taken antibiotics or whose immune systems are suppressed by drugs or serious illness, but it does not cause serious illness in normal people.
Claims have been made, however, that yeast can cause various problems even when there is no clinical evidence of infection. The list of problems attributed to yeast includes: fatigue; irritability; constipation; diarrhoea; abdominal bloating; mood swings; depression; anxiety; dizziness; weight gain; difficulty concentrating; muscle pain; joint pain; a craving for sugar or alcohol; psoriasis; hives; respiratory and ear problems; menstrual problems; infertility; impotence; bladder infections; prostatitis; and "feeling bad all over."
During the 1980s, several reports were published suggesting that some children had infections due to candida and later developed autism. It was also claimed that treating the candida infection with an antifungal drug led to improved functioning in children with autism. Some claim that the antifungal agent Nystatin should be given to children with autism whether or not they show signs of infection.
To date, the idea that yeast infections can cause or exacerbate autism has not been subjected to careful analysis.
It has been suggested that chemicals present in the environment may cause autism, and that the increasing load of such chemicals might explain the increasing numbers of children being found to have autism. Heavy metals, in particular mercury, have received a lot of publicity.
The largest source of environmental mercury is power plants powered by coal and gas, and it has been suggested that people living near such plants are exposed to high levels. Mercury, which is known to be toxic to the central nervous system, is also found in several large fish and was until recently found in some vaccines.
The (American) Food and Drug Administration (FDA) has issued warnings that women who are pregnant, and young children, should not eat shark, swordfish, king mackerel, or tilefish because they contain methyl mercury. After obtaining data from the FDA using the Freedom of Information Act, environmental groups added tuna to this list of potentially dangerous fish, based on the FDA's data. (Page A20. Boston Globe. 26 April 2000.)
The FDA has also moved to remove thimerosal, a mercury compound, from vaccines.
Thimerosal was used as a preservative (to prevent bacterial and fungal contamination) in some vaccines. As more vaccines were developed against more diseases, and children given more immunisations, they received an increasing load of mercury as thimerosal. It was then realised that normal infants given the recommended vaccines were receiving doses of mercury that exceeded guidelines issued by the (American) Environmental Protection Agency.
The (American) Institute of Medicine (IOM) was asked to investigate the connection between thimerosal and autism. In its report, the IOM stated that
Over the past four years, thimerosal-free vaccines have become available.
The current situation with mercury may be similar to that of lead a few years ago. Neither mercury nor lead occur naturally in the body, and they serve no known function in the body. Governments have made strenuous efforts to remove lead from from the environment by legislating the use of unleaded petrol (gasoline). It is possible that similar efforts to remove mercury from the environment will occur in the future.
Autism tends to improve as children mature, acquire language and learn to use it to communicate. This improvement may be particularly noticeable in those children who receive early behavioural and educational intervention. Behaviour may may deteriorate during adolescence partly due to hormonal changes and partly due to the difficulty of living in an increasingly complex world. Those with adequate social skills sometimes find a specialised niche that allows them to become independent and self-supporting.
About one child in three with classic autism will have two or more seizures at some point in childhood. The probability of having a seizure seems to be related to mental retardation and motor deficits. Children who are severely mentally retarded or have serious motor deficits are more likely to have seizures than other children.
The diagnosis of autism depends on the presence of a sufficient number of characteristic difficulties. Documenting these difficulties requires the taking of a careful medical and developmental history, and a description of current functional skills. If there are no clear indications of an underlying medical or neurological disorder, then blood tests and X-rays are not helpful, though it is usual to test for the presence of the Fragile X chromosome, which can cause symptoms similar to autism. If the history is suggestive of seizures, an EEG should be obtained.
The brain is a very complex organ. Its development and function are not completely understood or mapped. Thus, research into the pathology of the brain is complicated by an incomplete understanding of the normal.
Several abnormalities of the structure and function of the brain have been reported in children with autism, but none of these has been shown to be present in all children. Research in this area continues, using very sophisticated tests such as PET (positron emission tomography) scans which can show differences in function of discrete parts of the brain.
Raising a child with autism is a continuing search for answers. A searched characterised by detours, false starts, and "miraculous cures" that turn out to be less than miraculous and less than a cure. No drug or other treatment can "cure" autism, but early and intensive treatment of behavioural and communication difficulties has been shown to lead to significant improvement. Several other therapies may also be useful.
There is general agreement that education and behavior modification are the most important treatment modalities for autism, but there is no consensus as to which program is best or how intense the program needs to be. Parents therefore need to educate themselves about the various educational and behavioral options available to them, including the rationale for the program and and the results of treatment with this program.
The following are among the most popular programs:
These programs differ from each other, but they have in common:
The Son Rise program cannot be classified as educational or behavioural but has many followers. The philosophy behind this program is that attitude is important, and that the most important attitude is love and acceptance of the child. The idea seems to be that parents can break into the autistic child's world by simplifying the environment, joining him in rocking and spinning rituals, and gradually imposing some structured or semi-structured activities.
In addition to educating and "treating" the child, the families of children with autism need to learn:
Sensory integration therapy is provided as a part of, or in addition to, educational and behavioural programs. The premise is that many children with autism cannot integrate sensory input properly. As a result:
The therapy involves deep pressure, brushing, massage, vibration, and the use of play equipment such as inclines, balls, swings, and tunnels so as to elicit adaptive responses and "train" the child's brain to integrate input from the various senses. SI therapy is generally well accepted and seems to be very helpful for some children, especially those who over or under react to various environmental stimuli.
SI therapy has met with criticism because of a lack or controlled studies. However, a recently published study, though small, provides some evidence of improvement. In this study, ten children with autism were given 15 minutes of massage therapy before bedtime by their parents. Another ten children had Dr. Seuss stories read to them on the same schedule. After one month, changes in activity level, sleep problems, and stereotypical and off-task behaviours were measured in both groups. The children who received massage therapy demonstrated fewer stereotypical behaviours, more time on-task, fewer sleep problems, and better social behaviour.
Perhaps the most famous example of SI therapy is the "Squeeze Machine" designed and publicised by Dr. Temple Grandin. This machine allows the user to regulate deep pressure stimulation. Though it has not been carefully studied, it may be helpful for some children.
While no drug can cure autism, medication targeted towards specific symptoms can be very helpful:
If medications are tried, specific problems should be identified, specific goals should be set, and some effort should be made to measure the resultant changes as objectively as possible. All medications have side effects and some can interact with other medications. Therefore, medications need to be carefully monitored. They cannot replace the need for appropriate education and behavior management.
The potential effects of music therapy are currently being investigated as an adjunct to bone-marrow transplantation, obsessive compulsive disorder, autism, and attention deficit hyperactivity disorder. It seems to be generally accepted that music has a calming effect, so it may be helpful for relieving anxiety.
Children with autism often process music better than they process speech, and have an accurate memory for the lyrics of songs, so the possible use of music therapy in autism is intriguing. Although not a specific therapy for autism, music is readily available, inexpensive, can be used at home without specialised training, and does not have side-effects.
This form of therapy evolved because of autistic persons' frequent abnormal responses to sound. The premise behind AIT is that by listening to random variations in sounds the child's auditory processing system will adjust to the sounds and become normal. It involves listening to filtered, modulated music which presents sounds at varying pitch and volume. The typical program involves 2 daily half-hour sessions for about 10 consecutive days.
While this therapy would not be harmful, it is not clear how listening to random sounds would be better than listening to music, and there is no scientific evidence that the treatment is of any benefit.
Although some have suggested a link between chronic candidiasis (yeast infection) and autism, there is no generally accepted explanation for this association. Despite this, many parents have used "anti-yeast therapy" (diet or medication) to reduce the number of yeast organisms in the body and have reported improvement.
The "anti-yeast" diet is said to promote the growth of "friendly" bacteria which will overwhelm the yeast. The medication, Nystatin, kills yeast organisms.
Neither the connection between yeast and autism nor anti-yeast therapy has received careful scientific study.
Proponents of cranial therapy claim that autism is caused by the failure of the the dura mater (a tough covering of the brain) to expand properly as the child grows, resulting in compression of the brain. They claim that "The manual stretching of the restrictive dura mater by the use of CranioSacral Therapy techniques has provided impressive improvement in autism."
The truth is that the bones of the skull fuse into a solid plate of bone early in childhood and it is impossible to stretch the dura mater because it is located on the inside of this bony plate. Cranial therapy does not work, and has been clearly shown not to work.
The idea behind this treatment is that autism is the result of a brain injury of unknown origin, and that treatment to "retrain" the injured part(s) of the brain is beneficial. There are no data documenting the validity of this method.
Parents who wish to use a "neurologic" treatment for a child with autism would obtain better validated treatment from a physical therapist or occupational therapist with a background in neurodevelopment and sensory integration.
This technique involves a "facilitator" holding a disabled person's hand, arm, or shoulder to "facilitate" the latter's typing messages on a typewriter keyboard or similar device.
The rationale behind facilitated communication is that children with autism have difficulty with purposeful motor movements, that they have a "hidden literacy," and that his can be expressed by overcoming the motor problems.
When it was first introduced, facilitated communication was thought to be of considerable value, because it seemed to allow the previously non-communicative child with autism to communicate by typing messages.
However, careful scrutiny has shown that the so-called facilitators are, in fact, the source of the typed information.
This "technique" is of no value in the management of autism.
Because there is some evidence of disturbance of the the immune system in children with autism, the infusion of immune globulin has been suggested as a treatment. The results of this therapy have however been inconsistent, and as this is written (September 2002), there is uncertainty about the advisability of this treatment.
Secretin, a hormone which occurs naturally in the intestinal tract, received a lot of publicity following reports that it might improve behaviour in children with autism. Children with autism, who were being evaluated for diarrhoea, were given secretin as part of a diagnostic test, and were then reported to relate better to other people.
However, controlled studies comparing secretin to a placebo have demonstrated no clinically significant difference between the children given secretin and those given placebo. These studies are continuing.
There is no solid evidence that autism is caused by dietary deficiencies or excesses, but special diets and dietary supplements continue to be suggested as treatment.
However, many children with autism, especially toddlers and pre-schoolers, eat a restricted diet because of their sensory and behavioural problems, and further restricting their diet in order to avoid specific foods can lead to nutritional problems. Parents who wish to try a restricted diet should therefore obtain professional help.
The gluten and casein free diet is often suggested because of the possibility that casein and gluten may not be properly digested and that large molecules, peptides, might enter the bloodstream where they act as "endorphins" leading to the symptoms of autism.
This diet is difficult to follow, but parents who have tried it have reported improvements. There have been no controlled studies of this diet.
Researchers at the University of Stirling, Scotland, have suggested that some children with autism have abnormal fatty acid metabolism, and recommend supplementing the diet with fish oils rich in eicosapentaenoic acid (EPA) and gamma linoleic acid and with the antioxidant vitamin E. Parents of children enrolled in a small preliminary study reported reported less aggression and hyperactivity, and improved sleep. A larger study is planned.
The use of vitamin B6 as a treatment for autism continues to be suggested. However, vitamin B6 in large doses is toxic to the nervous system, and there are no properly controlled studies showing that it is helpful in children with autism.
Another purported treatment for autism is the use of special eye glasses, either tinted lenses or special prisms. There is no scientific basis for such glasses. If a child has a documented problem such as near or far sightedness, astigmatism, or squint then glasses may well be an appropriate treatment, but there is place for special glasses as a treatment of autism.
This term means different things to different people. Some people use the term to indicate autism without mental retardation, some to indicate Asperger's disorder, and some to indicate a pervasive developmental disorder not otherwise specified.
It is not clear if Asperger's is a separate disorder or a form of autism occurring in individuals with normal or high intelligence. Individuals with Asperger's have:
Children with Asperger's have been described as "too bright and articulate to qualify easily for supportive services, too impaired to function well without support."
Children with Asperger's have difficulty with conversation
This diagnosis indicates that a child has a severe and pervasive impairment of reciprocal social interaction associated with
The diagnosis of PDD-NOS is often used to indicate that a child has some of the defining characteristics of autism but not enough to make the diagnosis, and is sometimes used in very young children by doctors who want to protect families from the label of "autism."
Children with this syndrome have apparently normal speech development, but use this to distract adults so that they avoid having to meet the demands of their teachers and parents. It is not clear that this is actually a separate disorder.
Non-verbal learning disorders are characterised by difficulty integrating information in the non-dominant hemisphere of the brain. This is usually the right hemisphere and the term "Right Hemisphere Disorder" is also used.
Children with NVLD are described as "unable to see the forest for the trees." They have normal verbal language skills, but have difficulty with
There is some overlap between NVLD and Asperger's disorder.
Children with hyperlexia have a fascination with the printed word and an ability to read printed words beyond their ability to understand what they are reading. They may also have significant difficulty in understanding language as shown on the standardized tests. Between 18 months and 24 months parents are often amazed by the child's ability to name letters and numbers. By three years children with hyperlexia see printed words and read them, sometimes before they have really learned to talk.
The primary and essential cognitive deficit in these children seems to be a disorder in speech and language involving a severe deficit in the ability to comprehend language whether it is spoken or written, as opposed to dyslexia which involves only recognition and/or comprehension of written language.
About half of these children regress at 18 months of age. They become aloof, non-communicative, and more autistic-like, and then improve at about 24 months. The other half develop echolalia and can memorize chunks of language without understanding. These children may develop an idiosyncratic use of words.
Children with hyperlexia:
Often, the best clue to hyperlexia is the child's precocious ability to spell.
It should be noted that the diagnosis of hyperlexia does not apply to children who are precocious in reading but who do not exhibit a significant language disorder.
Children with Semantic Pragmatic Disorder have difficulty with communication. They have difficulty understanding what other people say, and they do not use speech appropriately themselves. Typical features include:
Most children with semantic pragmatic disorder also have some difficulty understanding social situations and expectations, and may be high functioning children with autism. Hence the idea of a "spectrum" of autistic disorders.
Dr. Christopher Gillberg of Gothenberg, Sweden described a group of children who had a combination of disorders of attention, motor coordination, and perception, some of whom had a diagnosable autistic disorder, usually similar to Asperger's disorder. It is not clear if DAMP is, in fact, a distinct disorder, and the validity of this disorder has been complicated by a dispute which is currently being determined by a law suit in the Swedish court system.
LKS occurs in children from 3 to 7 years of age. The major feature of LKS is the loss of the ability to use and understand spoken language. Children begin having difficulty understanding what is said to them. Most children with LKS have seizures, and all have abnormal electrical activity in the brain as measured by an EEG. Behavioural problems such as hyperactivity, aggression, and depression also occur.
Rett's Disorder occurs only in girls, and is characterised by:
This is a serious disorder in which there is at least 2 years of apparently normal development followed by a significant regression in several areas of functioning including language, social skills or adaptive behaviour, play, motor skills, and bowel or bladder control. The condition is usually associated with severe mental retardation.
This is not an autism spectrum disorder.
Sometimes, however, it can be very difficult to distinguish the rituals of an obsessive-compulsive child from the rituals and repetitive, fixed routines of children with autism.
This syndrome consists of mental retardation and social and communication difficulties characterised of autism. it is caused by a "fragile" site on the X chromosome.
A regulatory disorder is an impairment of the normal ability to process sensation(s), to receive information from the senses and respond (or not respond) to this information while staying calm and attentive. Infants with regulatory disorders may under-react or over-react to stimuli such as noises and bright lights. They may show "tactile defensiveness;" that is, they may stiffen and arch their bodies to avoid the physical handling associated with being dressed or held. They may under-react or over-react to pain. Or, they may have difficulty processing several stimuli simultaneously.
Consider, for example, a mother who strokes or rocks her baby while singing or talking to her. This normally developing infant is simultaneously exposed to a visual stimulus (the human face), an auditory stimulus (song or speech), a tactile stimulus (touching), and kinesthetic stimuli (rocking). A baby who has difficulty processing several sensations at the same time may be overwhelmed, and may "turn off" her processing of the human face.
This may interfere with the child's developing shared attention and reciprocal gesturing with her mother, compromising the development of communication and social relationships. Thus a "multi system developmental disorder."
Children who are born with impaired hearing have difficulty learning to use language, and their behaviour may suggest autism when they are young. As they mature, however, deaf children develop pretend play, and use gestures, body language, facial expressions, and sign language for communication. Any child who appears to be deaf should have a hearing evaluation.
Children with poor vision sometimes exhibit autistic like behaviour after their first birthday. Distinguishing the correct cause for this behaviour should not be too difficult.
All young children should have an eye examination and vision screening during the toddler years, so that problems with vision can be treated appropriately.
Young children who are deprived of love, affection, and stimulating experiences do not develop normal social skills, language skills, or cognitive skills, and may appear to be autistic. During the early 1990s, many such children were adopted from Romanian orphanages. Many of these children continue to have problems as they grow older.
An incomplete list.
Several medical conditions can cause the symptoms of autism in affected children, but are not considered to be part of the autism spectrum. These include tuberous sclerosis, phenylketonuria, neurofibromatosis, Down syndrome, and Fragile X syndrome.