Understanding Autism
Autism Spectrum Disorder (ASD) and autism are both common terms used for a group of complex neuro-developmental disorders Autism is a pervasive developmental disorder that involves abnormal development and function of the brain. Individuals with autism show decreased social communication skills and restricted or repetitive patterns of behaviors or interests.. Autism spectrum disorder impacts the nervous system and affects the overall cognitive, emotional, social and physical health of the affected individual. This section explains some of signs and symptoms of autism, deficits in their social, communication skills, the behavioural issues, associated problems with autism, related causes and the team involved in treating and diagnosing autism.
Autism Spectrum Disorder (ASD) and Autism are both common terms used for a group of complex neurodevelopmental disorders. ASD is primarily characterized by deficits in communication and social interactions, unusual behavior and interests, while impacting the nervous system and affecting overall cognitive, emotional, social and physical wellbeing of the individual. The signs and symptoms of autism are typically noticed in the first three years of life. Autism affects the way a child relates to his or her environment and their interaction with other people. Subsequently, this grossly impacts development in the areas of daily functioning and social interaction. Mental capacities may be compromised due to atypical (subnormal) functioning of some areas of the brain. Hence, children with Autism have special needs that must be addressed differently.
Autism is usually diagnosed in early childhood and despite extensive studies, the exact cause of Autism remains elusive. However, with increased awareness, rapidly evolving technology and ever-growing research, it is now understood that an intricate interplay of genetics and environmental factors may be responsible for the onset of Autism. Research has established that early diagnosis and intervention, along with access to appropriate support lead to significantly improved outcomes. When Autism is detected and treated early, disruptive behaviors can be minimized and the quality of life of the individual can be bettered and moulded significantly.
History of Autism
The root of the term "autism" is derived from the Greek word "autos" meaning "self".
Paul Eugen Bleuler, a Swiss psychiatrist, first coined the term in 1911 . He used it to describe a subset of schizophrenic patients who seemed to be self- absorbed and withdrawn. As time passed, our thinking and understanding of autism has evolved dramatically. An analysis of the description of behavior traits observed in several early documented cases suggests that these are in fact cases of what we now recognize as Autism. One famous and well documented example of this would be the story of Victor, the Wild Boy of Aveyron, who was found naked in a French forest. Victor did not understand language and would eat only half-burned or roasted potatoes, walnuts and raw chestnuts. Some even believed that he had been reared by wolves. The French physician Dr. Jean-Marc Gaspard Itard took Victor under his care and brought him to Paris. Dr. Itard spent several years trying to help Victor to integrate into human society and teaching him language. He was not completely successful as Victor only learned some French words, but never fully understood the language. However, there was an improvement in Victor’s fine motor skills and communication. He also developed a friendship with his caregivers. It is now known that Victor may have been autistic and whoever he lived with was unable to understand him. Hence, although Autism seems to be a new condition, a look at its history suggests that it may have always existed..
Dr. Leo Kanner (pronounced "conner") and Dr. Hans Asperger have played the most crucial roles in introducing Autism to the world. In 1943, Dr. Leo Kanner, an Austrian psychiatrist working at Johns Hopkins Hospital, published a paper describing 11 children who displayed a "strong desire of being alone", had a "resistance to change" or a "need for sameness". He introduced the term "early infantile autism" to describe his observations. A year later, Dr. Hans Asperger, also an Austrian psychiatrist, described similar characteristics in a group of children he was treating. It is was eventually accepted as a diagnosis in 1981 and coined as "Asperger’s Syndrome" by Dr Lorna Wing, an English Psychiatrist, who pioneered in child development disorders and advanced the perception of Autism, worldwide.
Prevalence of Autism
According to CDC, USA reports of March 24th 2023, 1 in 36 children have autism. The last decade has seen a significant jump in the incidence from 1 in 88 in 2012. This increase has been alarming. The prevalence of Autism varies considerably from country to country. No factors have been identified to contribute to the increased prevalence in different countries.
The studies have picked up a steep rise in the prevalence of autism.
Studies have also shown that boys are 5 times more likely to develop Autism than girls.
References:
1. Lord, C., Cook, E. H., Leventhal, B. L., & Amaral, D. G. (2013). Autism spectrum disorders. Autism: The Science of Mental Health, 28(2), 217.
2. Feinstein, A. (2011). A history of autism: Conversations with the pioneers. John Wiley & Sons.
3. Starostina, N. (2016). Victor, the Wild Boy of Aveyron (c. 1788 – 1828), and the Rise of Special Education in Modern France,
4. Baron-Cohen, S. (2015). Leo Kanner, Hans Asperger, and the discovery of autism. The Lancet, 386(10001), 1329-1330.
5. Kanner, L. (1943), Autistic Disturbances of Affective Contact, Nervous Child, 2, pp.217-250.
6. Kanner, L. (1946), Irrelevant and Metaphorical Language in Early Infantile Autism, American Journal of Psychiatry, 103, pp.242-246.
7. Kanner, L. & Eisenberg, L. (1956), Early Infantile Autism 1943-1955, American Journal of Orthopsychiatry, 26, pp.55-65.
8. Bender, L. (1982), In Memoriam Leo Kanner, MD June 13, 1894–April 4, 1981, J Am Acad Child Psychiatry 21(1): 88-89.
9. Asperger, H. (1944), Die ‘Autistischen Psychopathen’ im Kindesalter, Archiv fur Psychiatrie und Nervenkrankheiten, 117, pp.76-136.
10. Asperger, H. (1968), Zur Differentialdiagnose des Kindlichen Autismus, Acta paedopsychiatrica, 35, pp.136-145.
11. Asperger, H. (1979), Problems of Infantile Autism, Communication, 13, pp.45-52
Parents of children with autism usually have a few unanswered questions such as "How did my child develop autism?" "My child was absolutely fine and had even started to pick up a few words. What happened all of sudden?" "Is autism acquired?" "Could it have been prevented?" "Is it genetic?" "Can my other children also have autism?"
Medical science does not have answers for many of these questions, and although the "why" may never be known, what is becoming clearer with ongoing research is, "What is the fundamental problem in the brains of the children with Autism".
In autism, though the brain structure looks normal, there are functional abnormalities in specific regions of brain. This information, about the functioning of brain areas can be obtained from functional neuroimaging techniques like PET-CT scan and functional MRI scan of the brain. These imaging studies permit the study of the abnormal pattern of cortical activation in autism. These studies indicate that certain areas of the brain show reduced functioning like mesial temporal lobe (innermost part of the brain responsible for learning, understanding, memory, social interaction and abstract thinking), frontal lobe (the front part of the brain responsible for emotions and aggression) and cerebellum (responsible for balance, coordination, muscle tone and speech). Hence the dysfunction of these areas are responsible for problems seen in autism.
Positron Emission Tomography – Computed Tomography Scans showing areas of brain with reduced function
Research has also helped us to know that there isn’t one cause of autism but multiple risk factors that increase the risk of a child developing autism. Most cases of autism seem to be caused by a combination of autism risk genes and environmental factors influencing the early brain development. Over the last five years, scientists have identified a number of rare gene changes or mutations which have been associated with autism. Other factors related to children with autism and their parents that may contribute to increase the risk of Autism have also been identified. Along with these certain environmental factors have also been included in the risk factors for Autism.
Below mentioned are a few probable causes of autism:
Patient and family related factors:
Gastrointestinal Diseases
It has been observed that gut microbiota affects the brain development and function. This was especially observed during various mice studies which indicated abnormal psychiatric symptoms in mice with abnormal gut microbiota. This theory has been extrapolated in Autism as well. The two gut related factors that are postulated as causes in Autism are firstly, the abnormal micro bacterial population in the gut of the children and second, the impaired carbohydrate metabolism by the intestinal cell lining. Many abnormalities in the intestinal cell lining such as ileo-colonic lymphoid nodular hyperplasia, enterocolitis, gastritis, and esophagitis, have been observed in various studies. A disruption of enterocyte membrane with increase inflammation in the gut has also been seen. Inflammatory markers such as cytokines, immunoglobulins and lymphocyte profiles are known to be altered in children with Autism, which leads to an increased permeability of intestines, and deficient activity of enzymes. Studies have also shown a strong correlation between the severity of autism and gastrointestinal problems. Commonly, the GI disorders observed in children with Autism, are chronic constipation, diarrhoea, gastroesophageal reflux disorder (GERD) and a gluten or casein intolerance..
Genetics Factors
Genetic factors are thought to be some of the most significant causes for autism spectrum disorders. It was earlier estimated that genetics could explain the occurrence of autism in over 90% of patients, however, thorough studies later proved that this was an overestimate.
In a twin study conducted, it was found that many non-autistic co-twins had learning or social disabilities, thus, making it difficult to explain the occurrence of autism, purely on the basis of genetics. Therefore, whether or not a child would autistic, depends on how different genes interact with one another, what their penetrance or response to a certain feature or characteristic is, the defect in the gene, environmental triggers and many other factors
A common hypothesis is that autism is caused by the interaction of a genetic predisposition and an early environmental insult. There are several theories based on environmental factors that have been proposed to address the remaining risk. Some of these theories focus on prenatal environmental factors, such as agents that cause birth defects, and others focus on the environment after birth, such as children’s diets.
Recently it has been noticed that certain traits of the father of the child may also contribute as a risk factor for autism.
Paternal Age:
Studies have suggested that advanced paternal age is a risk factor for Autism. Men above the age of 45 years are thrice as prone to fathering children with Autism, as compared to 24 year old men. Men younger than 20 years are also at the risk of fathering children developing autism. This risk carries forward over generations, a study suggests if a father’s age is above 50 years, not only their children but their grandchildren also have a higher risk of developing autism.
Environmental factors:
Environmental factors play a role in increasing risk of Autism. With urbanization and industrialization we are exposed to chemical pollutants in air, water, soil and therefore even the food we eat. With advent of technology we are exposed to more and more electromagnetic radiations. These elements are presumed to contribute to increased risk of Autism.
We've all heard that electromagnetic radiations from the electronic devices we use affect brain function. To get down to the technicality of this statement, electromagnetic radiations can alter the biological electric activity of the brain, thus, increasing blood brain barrier permeability and inducing epigenetic modifications. This can therefore, potentially alter damage brain cells and thus affect brain development. Wireless radiations, especially, emitted from the gadgets we regularly use, such as cellphones, etc. can potentially contribute to neuroinflammation. Prolonged or regular exposure to wireless radiations during pregnancy may affect not just the mother, but also the fetus. Children exposed to constant wireless radiations early in the childhood may also experience harmful effects of the radiation. These radiations are presumed to interfere with the ability of human body to excrete heavy metals. This can lead to heavy metal accumulation inside cells thus, causing toxicity. Reducing the exposure to wireless radiation has shown reduction in the symptoms of Autism in some instances. Although, the evidence for the causative effect of these radiations is very minimal at the moment, it warrants further investigation.
Mercury:
Mercury poisoning has also been considered as one of the risk factors of autism. Mercury binds to Cysteine-Thiol which can damage brain cells. Glutathione prevents mercury binding to Cysteine-Thiol group. Glutathione levels in children with autism are significantly reduced as compared to a normal individual, in addition mercury cannot be excreted effectively in children with Autism. Therefore, mercury exposure can lead to toxicity in these children. Mercury toxicity can cause immune deficits, sensory deficits, motor deficits and behavioural abnormalities; all of these present in children with autism. However, this cause has not been very well validated. A meta-analysis published in 2007 concluded that there was no link between mercury and autism.
Lead
Lead levels as less as 10 μg/dl can cause aberrant learning and defective neurobehaviour in Autism. High levels of lead can cause permanent brain dysfunction, impaired cognition and learning, behavioural disorders, attention deficit, affected communication and social functioning.
Alluminium
Aluminium is a neurotoxin and a strong immune adjuvant, its neurotoxicity could be attributed to its impact of inducing oxidative stress and liberating DNAse which is a significant DNA damage inducer.
The MMR vaccine theory of autism is one of the most extensively debated theories regarding the origins of autism. There are different concerns regarding vaccination and its relationship with autism. Primary concern being the Measles – Mumps – Rubella (MMR) Vaccine itself causing autism, second one of the preservatives used in different vaccines causing autism and third simultaneous administration of multiple vaccines can overwhelm the immune system that leads to immune compromise causing autism.
There was a finding presented by a British Gastroenterologist in Dr. Andrew Wakefield who presented a case series of 8 children with Autism who were diagnosed of Autism 1 month after receiving the MMR vaccine. The findings in the paper, however, were refuted by many other scientists due to lack of control group and the inability to disprove the coincidental occurrence of autism in these children. There were approximately 40000 children receiving the vaccine every year in the UK and the prevalence of autism was 1 in 2000 children in 1998. Therefore, it was very likely that this could be an coincidental finding. This paper was later retracted by Lancet.
Twenty epidemiological studies thereafter from different countries with large enough population to detect even a minor effect of vaccines on autism have been conducted, all of these studies don't show any relation between vaccination and risk for Autism. The Centers for Disease Control and Prevention, the Institute of Medicine of the National Academy of Sciences, and the U.K. National Health Service have all concluded that there is no evidence of a link between the MMR vaccine and autism. As diseases like measles can cause severe disabilities and death, the risk of a child's death or disability due to not vaccinating a child is significantly larger than presumed risk of child developing Autism.
References:
1. Gastrointestinal flora and gastrointestinal status in children with autism-comparisons to typical children and correlation with autism severity. Adams JB, Johansen LJ, Powell LD, Quig D, Rubin RA BMC Gastroenterol. 2011 Mar 16; 11:22.
2. Normal gut microbiota modulates brain development and behavior. Heijtz, R. D., Wang, S., Anuar, F., Qian, Y., Björkholm, B., Samuelsson, A., … Pettersson, S. (2011). Proceedings of the National Academy of Sciences of the United States of America, 108(7), 3047–3052.
3. Impaired Carbohydrate Digestion and Transport and Mucosal Dysbiosis in the Intestines of Children with Autism and Gastrointestinal Disturbances. Williams, B. L., Hornig, M., Buie, T., Bauman, M. L., Cho Paik, M., Wick, I., … Lipkin, W. I. (2011). PLoS ONE, 6(9), e24585.
4. Biological plausibility of the gut-brain axis in autism. Vasquez A. Ann N Y Acad Sci. 2017 Nov;1408(1):5-6
5. Galuska L, Szakáll Jr S, Emri M, Oláh R, Varga J, Garai I, Kollár J, Pataki I, Trón L. PET and SPECT scans in autistic children. Orvosihetilap. 2002 May;143(21 Suppl 3):1302-4.
6. Chugani DC, Muzik O, Behen M, Rothermel R, Janisse JJ, Lee J, Chugani HT. Developmental changes in brain serotonin synthesis capacity in autistic and nonautistic children. Annals of neurology. 1999 Mar 1;45(3):287-95.
7. Schifter T, Hoffman JM, Hatten JR HP, Hanson MW, Coleman RE, DeLong GR. Neuroimaging in infantile autism. Journal of Child Neurology. 1994 Apr;9(2):155-61.
8. Mountz JM, Tolbert LC, Lill DW, Katholi CR, Liu HG. Functional deficits in autistic disorder: characterization by technetium-99m-HMPAO and SPECT. Journal of Nuclear Medicine. 1995 Jul 1;36(7):1156-62.
9. Zürcher NR, Bhanot A, McDougle CJ, Hooker JM. A systematic review of molecular imaging (PET and SPECT) in autism spectrum disorder: current state and future research opportunities. NeurosciBiobehav Rev. 2015 May;52:56-73.
10. Wang C, Geng H, Liu W, Zhang G. Prenatal, perinatal, and postnatal factors associated with autism: A meta-analysis. Medicine (Baltimore). 2017 May;96(18):e6696
11. Modabbernia A, Velthorst E, Reichenberg A. Environmental risk factors for autism: an evidence-based review of systematic reviews and meta-analyses. Mol Autism. 2017 Mar 17;8:13
12. Wakefield AJ, Murch SH, Anthony A, Linnell J, Casson DM, Malik M, Berelowitz M, Dhillon AP, Thomson MA, Harvey P, Valentine A. RETRACTED: Ileal-lymphoid-nodular hyperplasia, non-specific colitis, and pervasive developmental disorder in children.
13. Plotkin S, Gerber JS, Offit PA. Vaccines and autism: a tale of shifting hypotheses. Clinical Infectious Diseases. 2009 Feb 15;48(4):456-61.
Children who are diagnosed with Autism are known to have other co-existing problems. A thorough evaluation is needed to rule out whether the comorbidity is directly associated with ASD or is altogether a different condition in the child.
Some of the problems which may be associated with Autism are described below
Autism is a neuro-developmental condition and the symptoms sometimes may not be evident in the early years of the child. Sometimes the late diagnosis is due to limited awareness of parents as well as denial or hesitancy in accepting their child’s problems. It is important that the parents are alert and aware of child’s behavior and if they spot anything that raises suspicion, they should immediately consult the professionals.
Diagnosis of Autism is done by a multidisciplinary team. Multidisciplinary team is a team of different professionals that look different aspects of child’s development and therefore can provide a more accurate diagnosis.
Professionals involved in diagnosing Autism
Psychiatrist | Pediatric neurologists |
Child Psychologist | Occupational Therapist |
Development Pediatrican | Speech and Language Pathologist |
This team carries out several assessments and tests, which pinpoint the exact areas in which the child has a problem. There are several tests that can be used for screening and diagnosis of autism. Screening of Autism involves identification of early signs and symptoms of Autism during regular visits to the pediatrician and appropriate referrals for details diagnostic evaluation. Diagnostic evaluation is more detailed and involves not only tests but other investigations. Some of the common tests used for screening and diagnosis are Childhood Autism Rating Scale (CARS), Autism Behaviour Checklist (ABC), Autism Spectrum Rating scale (ASRS), Autism Diagnostic Observation Schedule (ADOS) and Indian Scale for Assessment of Autism (ISAA). The criteria used for diagnosing autism by Psychologists is the fifth diagnostic and statistical manual for psychiatric disorders (DSM-V). For detailed DSM-V criteria click here
This assessment will aid in establishing a diagnosis as well as severity of ASD. These details will help to formulate a focused personalized treatment plan for your child.
Prior to diagnosis based on clinical observations and standardized assessment tools, you may be requested to perform one or more of the following investigative procedures for your child. These will help in ruling out other possible problems.
Neuro-imaging studies
Magnetic Resonance Imaging (MRI)
Magnetic Resonance Imaging scan of the brain reveals the structure of the brain and distribution of various tissues in the brain. Therefore, it can spot any structural abnormality including brain malformations, non-formation of any of the brains parts, presence of tumors, abnormal accumulation of the fluid in the brain etc.
Before the test:
Your child may be required to be fasting before the test, therefore consult your doctor for the same. Your child may be sedated during the test to avoid any body movements as the movements interfere with the quality of imaging. Sedation is process of administering special medicines that make him/her fall asleep. The test is conducted in the magnetic field and therefore make sure that your child is wearing no objects or clothes containing metal. If there are any metallic implants in the body, consult with your doctor for the same.
During the test:
Once the child is sedated he / she will be taken in the special room where for scanning. You may or may not be allowed to accompany the child. It may take up- to 30 – 45 mins for the scanning. The test is not painful and there are no side effects.
After the test:
Care should be taken when the effect of sedation is wearing off. There are no special instructions to be followed once the child is awake.
How to interpret the results:
The results will be given to you in two forms, first a print of the films and a CD containing the entire MRI study and second an interpretation and report by a radiologist after having analyzed the study. In most of the cases of Autism the MRI of the brain may be near normal. Therefore you may be advised to do functional neuroimaging
A typical MRI Machine: It is a non- invasive method which uses a powerful magnetic field and radio frequency impulses. A computer is used to produce detailed images of internal structures like bones, soft tissue, organs, etc.
Image courtesy: Flickr
Positron Emission Tomography – Computed Tomography (PET-CT) scan
Positron Emission Tomography – Computed Tomography (PET-CT) scan is a technique of functional imaging of the brain. PET-CT scan is performed by injecting radioactive dye intravenous and then the amount of dye absorbed by the brain tissue is recorded. The radioactive dye is similar to glucose in its composition and hence is readily absorbed by the brain cells.
Before the test:
Your child may be required to be fasting before the test, therefore consult your doctor for the same. Your child may be sedated during the test to avoid any body movements and any brain stimulation as it may interfere with the results of the study. The test is conducted in the magnetic field and therefore make sure that your child is wearing no objects or clothes containing metal. If there are any metallic implants in the body, consult with your doctor for the same.
During the test:
Your child may be required to be fasting before the test, therefore consult your doctor for the same. Your child may be sedated during the test to avoid any body movements and any brain stimulation as it may interfere with the results of the study. The test is conducted in the magnetic field and therefore make sure that your child is wearing no objects or clothes containing metal. If there are any metallic implants in the body, consult with your doctor for the same.
After the test:
Care should be taken when the effect of sedation is wearing off. There are no special instructions to be followed once the child is awake.
How to interpret the results:
A radioactive dye will be injected intravenous approximately 45 minutes before the test. The duration of this may vary. Once the child is sedated he / she will be taken in the special room where for scanning. You may or may not be allowed to accompany the child. It may take up-to 30 mins for the scanning. The test is not painful and there are no side effects.
PET-CT Scan: This is a nuclear imaging technique which reveals both structural and functional details of cells and tissues, in a single imaging session.
Image courtesy: Commons
Brain Stem Evoked Response Audiometry (BERA):
In children with Autism it is seen that there is a delay in speech or failure to respond to name-call. It is then that your doctor may recommend a BERA test to rule out any hearing problems. BERA is an objective method of picking up brain stem (part that connects brain and spine) potentials in response to audiological click sounds. These waves are recorded by electrodes placed over the scalp. This test helps in ruling out hearing deficits.
After the test:
Care should be taken when the effect of sedation is wearing off. There are no special instructions to be followed once the child is awake.
How to interpret the results:
The results will be given to you in two forms, first a print of the films and a CD containing the entire PET-CT study and second an interpretation and report by a nuclear medicine expert after having analyzed the study. This study will show the areas of the brain that are functioning lower than normal (hypofunctioning) as well as more than normal function (hyperfunctioning).
Research has implied that there could be problems related to the functioning of the temporal lobes of the brain, including hippocampus and amygdala. These areas are responsible for organizing sensory input, auditory perception, language and speech production, memory association formation and emotional expression etc. These co-relate to the kind of issues seen in Autism. Another area, which appears to be affected, is the cerebellum, which is important for information processing, balance and coordination.
ASD is a heterogeneous disorder i.e. no two individuals on the spectrum will have the same set of signs and symptoms. The severity and range of symptoms are highly variable. However, the symptoms or difficulties can be classified into core domains such as difficulty in social interactions, communication deficits, behavioral issues and unusual interests and certain physical attributes. An individual may present with anyone, or a combination of or all of these difficulties/symptoms. Signs and symptoms usually become noticeable in the first three years of life. This section details the range of these signs and symptoms which are usually observed in individuals with autism.
Individuals with ASD face difficulties in communicating and expressing their feelings. They also have trouble in understanding the feelings of the people around them. As they grow up, this social deficit is further affected due to feelings of anxiety and depression. This in turn intensifies the problem with social skills, making it hard for them to adjust or adapt to their surroundings.
Examples of Social Issues related to ASD:
- Poor or fleeting eye contact
- Delayed or lack of response to name
- Isolated play (the child prefers to be aloof)
- Inability to interpret gestures or non-verbal cues
- Difficulty in expressing feelings
- Lack of social awareness (difficulty in understanding personal space and boundaries)
- Sensory issues (avoids touch or seeks more physical touch for example hugging, kissing, etc.)
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