Аlexander Statnikov—methodologist, City Psychological and Pedagogical
Centre of the Moscow Department of Education State Budgetary Institution
There are many different kinds of neurological development that can manifest themselves through various combinations of behavioral, emotional, motor, and learning disabilities. Such disabilities can result in special demands on a person's social surroundings (for example, the organization of museum spaces). In this article, an attempt will be made to briefly characterize the most commonplace disabilities of learning and sensory processes among people with learning and developmental disorders (LDD)1 and autism spectrum disorders (ASD).
A majority of the disabilities mentioned in this article are not specific to a particular type of development. They can be manifest by various types of people in various combinations. In addition, certain variations of neurodevelopment can accompany each other: oftentimes, developmental disabilities are observed in conjunction with ASD2 ; as a result, even if certain disabilities can be conditionally categorized as one of these variants, this does not exclude the possibility of their coexistence.
Currently, a broad spectrum of neurodevelopmental variations, unified by the following three characteristics, are understood to fall under the term 'developmental disorders':
- Intellectual disabilities that can affect:
- Logical thinking;
- Problem-solving abilities;
- Planning abilities;
- Abstract thinking;
- Critical thinking capabilities;
- Capacity for academic study (mastery of the school curriculum);
- Cognitive abilities in everyday situations (learning by trial and error, learning by observation).
- Difficulties or deficit in the mastery of critical life skills, which can be expressed in various spheres of life like:
- Social skills;
- Independence in everyday and community life;
- Receiving education and/or performing labor.
- The existence of the two aforementioned characteristics in infancy or childhood.
The forms and degrees to which LDD can manifest themselves vary widely. There is a tradition of dividing them into expressed, moderate, and mild: formally, the line is drawn based on coefficient of intellect (IQ). The reasons for their appearance are equally varied: many cases of LDDs are due to genetic causes (Down syndrome, for instance, or fragile X syndrome) or complications during pregnancy or birth, the influence of various diseases or toxic substances, a lack of essential nutrients in a child's or mother's diet, an iodine deficit and so on.
Below are the main characteristics of information processing processes that may be present among people with LDDs and which are worthy of focus when adapting both environments and forms of delivering material.
Difficulties in performing mental operations
One of the main characteristics of LDDs is difficulties in performing high-level mental operations—specifically, those connected with verbal and logical thinking. Difficulties in identifying a significant feature can serve as an example: as a rule, a person with typical neurodevelopment will have no trouble saying what a blanket, a terry robe, and a cotton ball have in common (they are all soft), whereas people with pronounced developmental delays might find such a task to be impossible. In more mild cases, people may be able to distinguish specific, tangible features but have difficulty distinguishing abstract ones like “materiality” (when it comes to distinguishing objects of external reality from ideas, etc.).
Abstract thinking abilities are closely related to the ability to generalize, most clearly manifested in the ability to combine objects into categories: for example, a table, chair, and wardrobe can be grouped together as “furniture.” This categorization permits further judgments as well (for example, the understanding that you should look for a new chair in a furniture store). With some degree of simplification, we can say that for people with LDDs, concrete thinking prevails over abstract. Another common feature of thought processes among those with delayed intellectual development is difficulty with establishing cause-and-effect relationships.
Characteristics of working memory
In cognitive psychology,3 “working memory” is understood as mentally holding and using information (Diamond et al., 2007). In other words, working memory is necessary in order to simultaneously hold several objects on one semantic level in the field of attention and work with them in the mental space. The semantic level varies: this can be several paintings that a person is comparing based on their overall emotional impression from them. On another semantic level, several human figures may be considered within the same canvas: for example, when a viewer tries to determine the symbolic meaning of these figures' location in the picture, or even a few specific brushstrokes (if we are talking about trying to determine the history of the painting's creation or later revisions to it). As a rule, the average person is able to hold five to nine semantic units in their mind's eye for a short period of time.
Studies show that people with LDDs have reduced working memory (Numminen et al., 2000). They have a hard time keeping several semantic units in mind at once and performing cognitive operations with them.
Characteristics of neurodynamic aspects of cognitive activity
We customarily understand the neurodynamic aspects of cognitive activity to mean both the speed of thought processes and the rate of increase in fatigue phenomena during cognitive activity, as well as specific patterns of changes in mental performance indicators: for example, difficulties in beginning tasks and switching between them.
Reduction in the speed of information processing
As a rule, people with LDDs need more time to process information than their neurotypical peers, although the results may vary from person to person and differ based on the modality in which the task is presented (verbally or visually). One of the spheres of life where the reduction in information processing speeds may be most visible is in social interactions, in which people often need to quickly get their bearings in a multi-faceted situation and give the right answers.
Difficulties in switching
People with LDDs often have difficulty switching: they need more time and organizational assistance in order to move from one cognitive task to another, especially if we are discussing a change in the type of activity (for example, switching from examination to answering questions). One particular case is difficulty with entering into an action, when beginning a new type of activity takes longer and requires more effort than for a neurotypical person.
In research, one can find comments that these difficulties are heterogeneous and may depend on the type of activity: for example, they may be practically absent when solving sensorimotor problems, but they are very clearly felt when solving intellectual tasks.
Autism spectrum disorders
The term “autism spectrum disorders” currently denotes many variants of neurodevelopment, united by two key traits: stable deficiencies in social communication and interaction, as well as limitations and repetition in the structure of behaviors, interests, or activities. The reasons behind the appearance of ASDs have still not been ascertained to this day—it is clear that a significant role is played by genetics, but not all cases where ASDs appear can be explained by mechanisms of heredity. Various hypotheses have been put forward, including the impact of toxic factors and unfavorable environmental conditions during pregnancy, consequences of organic lesions of the central nervous system, metabolic and immune characteristics, and so on. Numerous studies show that ASDs are also often accompanied by one or more characteristics of processing of both information and the sensory sphere. The most common such characteristics are described below.4
“Central binding” deficit
I am unable to hold one piece of information in my mind while I do the next step.
Temple Grandin, adult with ASD
Imagine that you need to put a point in the center of the circle, and you can only see either the pencil or the circle itself, but not both things at the same time. A central binding deficit can be described as an inability to (or significant difficulties in) simultaneous perception of several elements of a situation in their connection among themselves. In other words, at the current moment, a person is able to focus on one thing, but it is difficult to connect that thing with other things within their field of perception. Details can be perceived very well or even “swallow” the attention of a person with a central binding deficit. As a result, information processing does not occur simultaneously, as for most people, but sequentially (and more slowly). Central binding deficits can extend to different aspects of perception as well. If we are talking about the auditory modality, then there may be situations when individual words are clearly heard and understood, but the general meaning of the sentence repeatedly escapes the listener. One particular case of such difficulties would appear to be difficulties in understanding figurative meaning and humor: after all, to understand a joke, you need to both correctly decode the literal meaning of your interlocutor's entire statement but also find its relationship to its context. Central binding also presumes the connection of information received through different channels of perception. A deficit in this area means that a person cannot draw parallels between facial expression and intonation, among other things, making it difficult to understand the meaning of what is being said.
I loved repetition. Every time I turned on a light, I knew what would happen.
When I flipped the switch, the light went on.
It gave me a wonderful feeling of security because it was exactly the same each time.
Sean Barron, adult with ASD
Previously, difficulties in switching between different types of cognitive activity were already examined. Rigidity (including in the perceptive sphere) can be considered one particular manifestation of this. Rigidity is defined as “a difficulty (up to and including total inability) to change the intended pattern of activity in conditions demanding its adjustment” (Kratkiy psikhologicheskiy slovar [Abridged Psychological Dictionary], 1998). An attempt to shift the “mind's eye” to another element of the situation can take a long time and require a lot of effort. With ASD, this difficulty may take on a “grotesque” form. There are frequent cases of being engrossed in static or moving objects (when a person looks fixedly at one thing—for example, at the play of light within a glass vessel—and can only be distracted with extreme difficulty) which are accompanied by significant discomfort in the event of a change, especially an unexpected one. It is assumed that this can lead to panic and breakdowns when faced with unforeseen circumstances, as well as monotonous actions and stereotypical behavior.
Difficulties in speech development
Different types of neurodevelopment often explain challenges in the realm of speech. In general, there are two broad categories: difficulties in speech comprehension and difficulties in speech formation.
Difficulties in speech comprehension
These disabilities can range from a complete lack of comprehension to more localized difficulties (for example, problems understanding grammatically complex sentences). Often, such difficulties mean that the processing of spoken information takes much longer than normally developing peers. In this case, a quick presentation of information “by ear” might result in a person being “turned off” from the communication situation or provoke negative emotional reactions.
Difficulties in speech formation
Communication disorders are one of the key signs of autism spectrum disorders. Still, the state of expressive speech also varies, from the complete absence of oral speech to its presence in a developed form amid difficulties in adequately applying these skills to a social context.
The following phenomena are most frequently encountered among individuals with ASD:
- Mutism: the complete absence of communication in a person—which, however, presumes the preservation of speech function. Speech may occur due to acute emotions or high body temperature. There is also a type of mutism called selective mutism, in which a person engages in communication with a very limited number of people.
- Echolalia: the systematic repetition of the last syllable, word, or words of the speaker. This may happen completely automatically, or it may have a communicative function. In this case, the person repeating adds their own meaning to it (sometimes with an intonation change).
- Word stamps: sometimes, the speech of individuals with ASD is limited to a small selection of words that are repeated mechanically. As with echolalia, this reproduction can be completely automatic or communicative (such as when a person tries to convey a certain idea using their stamps: the speech repertoire might feature one phrase for pleasure and another for displeasure). It is also possible that the repetition of these words may serve as self-stimulation if the person gets pleasure from the very act of speech and the sensory sensations associated with it.
- Phonographic speech: sometimes, people with ASD construct long and grammatically correct statements, but their speech is nevertheless primarily monologic in nature, and having a simple dialogue turns out to be challenging.
- Autonomy of speech: the general term for the majority of phenomena in which speech is not communicative in nature.
Also, ASD may be accompanied by speech characteristics that are not specific to this type of neurodevelopment: various difficulties with pronunciation (from complete incomprehensibility to difficulties in articulating individual sounds), grammatical disorders, and difficulties and errors in word choice.
In some cases, people with ASD experience hyperlexia, in which well-developed reading (and possibly writing) abilities exist against the background of significant difficulties with or almost total lack of oral speech.
Deficit in theory of mind
Theory of mind is the ability to take the position of a different person and recognize the individual notions, feelings, and intentions that they may have. A classical test to determine the level of development of this ability is the so-called Sally-Anne test.
There are two girls, Sally and Anne. Sally has a basket, and Anne has a box. Sally has a ball. She puts the ball in the basket and goes for a walk. While Sally is gone, Anne puts the ball in the box. Sally returns and wants to play with her ball. Where will she look for it?
A person who can take another person's position will probably assume that Sally will look for the ball in the basket first (after all, the girl didn't see Anne move it). However, many people with ASD experience difficulties solving this problem, along with similar real-life situations when one must look at a situation through an interlocutor's eyes.
It is assumed that one of the important sub-components of theory of mind is joint attention: the ability to communicate with a person while maintaining focus on a shared object for both of you. For example, a mother can show a child a teddy bear (with a gesture or a look) and say: “Soft.” If the child is able to use joint attention, they will understand that she is talking about the toy. If not, they probably won't be able to figure out what exactly their mother meant.
Difficulty in recognizing emotions
I wanted to understand emotions. I had dictionary definitions for mmm moo them and cartoon caricatures of others… I also had trouble reading what other people felt. I could make some translations, though. If people's voices got louder, faster, or went up, they were angry. If tears rolled down their faces, or the sides of their mouths hung down, they were sad. If they were shaking, they were perhaps frightened, sick, or cold.
Donna Williams, adult with ASD
This quote reflects a common characteristic of perception among people with ASD: they often either do not recognize the signs of emotions or interpret them incorrectly. Studies using eye-tracking5 technology show that as a rule, in visual analysis of expressive emotions, people with ASD don't look at the parts of the face that are the most informative in terms of emotions. Instead of eyes and a mouth, their gaze might stop on the forehead or chin, for instance.
In some cases, difficulty in recognizing emotions can also extend to oneself: it is difficult for some people to understand what they are feeling at the present moment. This can significantly complicate self-regulation and control of one's own behavior.
Hyper- and hypoesthesia
Many people can't stand certain sounds: the rubbing of Styrofoam on glass, the rustle of a bag or dry paper, the scrape of dry chalk on a chalkboard, and so on. Some people even feel a sense of physical discomfort when they hear such sounds. Now imagine that any sound louder than a whisper causes a similar effect. Or another person's touch. Or the color red. All these can be considered special cases of increased sensitivity, or hyperesthesia, which is often present in the lives of people with ASD. The opposite, hypoesthesia—reduced sensitivity—is also common among people with ASD. Specific manifestations of hyper- and hypoesthesia in various modes of perception will be discussed in a little more detail later.
Hyperesthesias in the visual modality can manifest themselves as intolerance to bright light or specific color combinations. Some self-reports offer the metaphor of distorted vision, when objects and sources of light seem to 'jump.'
For those with visual hypoesthesias, objects frequently look dim or even deprived of certain qualities. Often, reduced visual sensitivity can express itself in difficulties with depth perception, which can lead to problems when throwing and catching objects, and other manifestations of clumsiness.
It is worth separately noting certain characteristics of perception like peripheral and tunnel vision. The former is more common in people with ASDs: information about objects at the edge of the visual field while objects located directly in front of a person are not perceived or poorly perceived (blurry or unclear). Tunnel vision is the opposite situation, where objects close to the edge of the field of vision are completely ignored or perceived as unclear.
Hyperesthesia in the audial modality can result in sounds seeming loud and/or distorted, or the impossibility to distinguish individual words. Sometimes, a person may literally have very sharp hearing and is able to hear conversations at a great distance. At the same time, there may be an inability to filter out signal from noise or identify the sound sources that demand immediate focus (for example, the voices of the people in one's current conversation).
Hearing hypoesthesias can manifest themselves in people perceiving only that information that arrives in one ear or only perceiving specific categories of sounds. They may also enjoy time spent in noisy, crowded spaces or loud noises made by environmental elements (such as slamming doors).
People with hyperesthesias of the olfactory organs may find smells too intense or even unbearable. This can lead to antipathy towards people using particular perfumes, shampoos, and so on.
Olfactory hypoesthesias result in an inability to sense smells, even the very strongest ones (including those of one's own body). Presumably, this type of reduced sensitivity also plays a role in the desire to taste different things, including those not intended for tasting.
Tactile hyperesthesias are also fairly common. Touches can feel both painful and unpleasant. Wearing shoes and/or gloves may cause discomfort. Washing and combing one's hair also become painful procedures due to the increased sensitivity of the scalp. The consistency of certain foods can be disgusting, as can certain types of fabric.
Hypoesthesias in the tactile sphere lead to increased pain thresholds (to the point that there may be a threat to a person's life due to insensitivity to pain). In addition, reduced sensitivity may be connected with the appearance of behavior intended to “overwhelm” this channel of information: it is assumed that in the search for tactile sensations, a person might squeeze other people or objects too strongly, engage in self-harm, chew inedible objects, and want to be crushed by something heavy.
Hyperesthesias of vestibular sensitivity include those elements of the nervous system responsible for balance, as a result of which any significant change in body position can lead to a sharp feeling of discomfort. As a result, there may be difficulties playing games and or sports, severe motion sickness in vehicles, and problems with cycling or other activities that involve maintaining balance and postures other than “feet down, head up.”
The question of whether this type of hypoesthesia indeed exists is controversial, but some researchers believe that people with low vestibular sensitivity tend to search for sensations that overload their balance system constantly. According to this hypothesis, such people might constantly sway, jump, or spin around.
Sense of distance
Psychologists often talk about personal space, often in the form of a metaphorical “air bubble” that surrounds a person: the zone into which we can only allow those people who are really close to us. The size and shape of this “bubble” depend on many factors. It is assumed that the most important role is played by the culture in which a person grew up, but individual differences obviously contribute as well. People with ASD often have difficulties adequately assessing appropriate distance for communication.
A lacking or significantly weakened sense of distance can be observed: a person may approach other people too close or even touch them without realizing that it may be unpleasant to the people around them.
The opposite situation is also possible: when a person has clearly defined boundaries of personal space, and any intrusion into them is perceived as an extremely unpleasant event.
This characteristic of perception can hardly be called an independent phenomenon. It is more commonly produced by those already mentioned: difficulties with central binding, understanding of speech, and different types of hyperesthesia. Nevertheless, people with ASD often note that too much information results in serious stress, anxiety, and feelings similar to physical pain. Sensory overload sometimes leads to such reactions as tuning out of a situation, sharp changes in behavioral patterns, and “explosions.”
Self-injurious behavior (SIB) is not a characteristic of information processing but is found fairly often in people with ASD (25–50% of cases). SIB includes various forms of physical harm to oneself. The frequency, intensity, form of behavior, and triggering factors of SIB can vary greatly from person to person. They include head-beating, self-cutting, biting and scratching oneself, hair-pulling, and so on. As a rule, in contrast to episodes of “impulsive” SIB that occur during neurotypical development, “stereotypical” SIB is delineated and characterized by the regularity of occurrence and the monotony of a person's actions.
The reasons behind SIB are the subject of intense study. Apparently, it is not an independent phenomenon in most cases but occurs and is reinforced in the behavioral repertoire of people with ASD due to a combination of various developmental features with certain environmental reactions. Various hypotheses have been put forward about the root causes behind SIB: the search for specific somatosensory sensations, the expression and/or masking of pain sensations (when a person might beat themselves against various objects to relieve existing pain), an increase in predictability of action and a reaction to sensory overload. Research is being conducted on the relationship of SIB to psychiatric diseases that may accompany ASD and other types of development, as well as research on the relationship between SIB and genetically determined aspects of physiological processes. A large body of work is devoted to the functional analysis of SIB: it is assumed that SIB can perform various functions due to the limited set of communication tools for people with ASD, such as getting what a person wants, avoiding requirements, and attracting attention to oneself.
There are various ways of responding to SID. When using the methods that fall under the umbrella of applied behavioral analysis, human behavior is carefully studied, and then a special plan is created, including a detailed description of environmental changes and possible actions for other people targeted at decreasing this behavior. Even in the absence of such procedures, the person's friends and loved ones (or the person with a disability themselves) have, as a rule, developed a set of actions that allow them to prevent/stop an episode of SID. Therefore, before a person with ASD visits a public space, you should ask them or their accompanying person about the potential for SID, if possible, and how to respond to it. If this is not possible, use the following advice from the National Autistic Society of the UK 6. Here are some of them:
- Try to respond to the behavior as calmly as possible.
Do not comment and keep a straight face. Your emotional response may amplify the negative behavior. Speak calmly and clearly, without raising your voice.
- Relax your demands.
Maybe you asked them to solve a task that was too difficult or asked a question that was too complicated.
- Remove the unpleasant sensory stimulus (sound, smell, light) or try to reduce its effect. If there is a sensory unloading area (a 'quiet room'), maybe it's worth bringing the person there.
- Help the person cope with discomfort: perhaps the person is experiencing physical pain (for example, a headache or abdominal pain). You should try to reduce the pain with help from people who have the right to give the person medicine.
- Try to attract the person's attention, call them by their name, and give them simple instructions that they can follow instead of the self-injurious behavior. For example: “John, put your hands on your chest.” Use visual cues to reinforce understanding of the instructions.
- Quickly switch the person over to another activity that will not allow them to continue hurting themselves (for example, something that must be done with two hands). Give them encouragement and praise (“John, you play with cars so well!”).
- If the person is having difficulty stopping their self-harm, you can help them gently—for example, by holding their hands. Try to immediately switch them over to another activity, but be prepared to keep them from trying to harm themselves again. This approach should be used with the utmost caution since it is likely to increase undesirable behavior or direct the person's aggression towards others.
- You can also place a physical barrier that will not let a person cause themselves harm, such as:
- If a person is hitting themselves in the head, place your palm or a pillow under their hand.
- If a person is biting their hands, let them bite another object.
Instead of a conclusion
The article considered the most common characteristics of information processing and sensory perception in people with LDDs and ASD 7. The article considered the most common characteristics of information processing and sensory perception in people with LDDs and ASD. It should be emphasized that at the moment, there is no convincing data confirming that a single one of the aforementioned characteristics necessarily accompanies ASD: someone may have one of them, another might have several, and a third person might probably have none. A similar situation is observed with LDDs since the very concept of a “learning and developmental disorder” is an umbrella term that covers many different types of intellectual difficulties, all of which are manifested differently in different people.
At least three important points remain outside our scope. The matter of emotional development and the relationship between cognition and affect is not covered, although it is obvious that some of the features listed in the article are associated with certain emotional reactions—primarily with fear and anxiety, most likely. An expansive class of behavioral features, such as stereotypical behavior and deficits in the development of executive function, can be considered in relation to ASD 8 (the latter being relevant to people with LDDs as well). In addition, it would be useful to provide recommendations for possible environmental and behavioral changes for those who work with developmental disabilities and ASD, but the format and topic of this article allow us to only briefly list the main groups of possible measures 9.
First, if such a possibility exists and does not violate principles of ethics or personal privacy, try to find out in advance about the specific characteristics of the person or group of people with whom you are going to communicate. It is possible that they already have information about the characteristics you may encounter, the specific ways of communication your interlocutor might use, and how to respond to certain behaviors.
Second, try to prepare the environment ahead of time. Although there are no universal recipes for success, we want to talk about “minimizing” as a rule: reduce the intensity of light, reduce noise, and remove distractions. Another important component of environmental preparation is its structuring and level of predictability. Many people with LDDs and ASD can be helped by visual support tools, such as visual plans (premises and scenarios of events) and images of the appropriate sequence of actions shown as pictorial rules of behavior. If possible, it also makes sense to create a special sensory relief zone for people with ASD. For people with LDD, it makes sense to plan the environment and prepare information so as to reduce the need to keep more than three semantic units in mind at any one time.
Third, prepare yourself: avoid bright clothing and strong-smelling cosmetics. Also, while communicating, try to keep track of the pace of your own speech, the time you give your interlocutors to think about what you have said, and the simplicity of the grammatical constructions you use. It will most likely be appropriate to add doses of “social” information in communication, such as references to complex experiences of other people, metaphors, humor, idiomatic expressions, and so on.
1. This term defines one of the types of developmental disorders. It is recorded in the Diagnostical Statistical Manual of Mental Disorders, 5th Edition is the most complete existing classification of neurodevelopmental disorders and psychiatric illnesses. In the Russian version of the International Classification of Diseases, 11th Revision, the term' intellectual disability' will most likely be used. Detailed characteristics of LDDs will be presented later in the article. Earlier, this type of neurodevelopment was often referred to as 'mental retardation
2. Currently, there is no single opinion on what percentage of people with ASD have developmental disorders, which seems to be connected with the specific methodologies used for evaluation and the populations studied. In the literature, numbers ranging from 38 to 70% can be found (Bayo, 2012; Postorino et al., 2016; Matson & Shoemaker, 2009).
3. The field of psychological science that studies learning processes— memory, attention, thinking, and so on.
4. From a specific theoretical perspective, some of the aforementioned characteristics might be a result of other, while some purportedly play the role of central mechanisms for determining specific subtypes of ASDs. This article is of a descriptive nature and does not pretend to determine such cause-and-effect relationships.
5. Technologies that analyze the movement of the point of regard when viewing images, reading texts, or solving tasks.
7. This is described in detail in Charles Njiokiktjien's book, 'Pediatric Behavioural Neurology' (Njiokiktjien, 2018).
8. As a rule, this term is understood to mean the ability to construct programmes of action, storing such programmes in memory, following them through to completion, resistance to distraction, and the ability to reject inappropriate impulses.
9. In Russian, a more extensive version of recommendations people with ASF can be found in the textbook Druzhelyubnyy muzey [Friendly Museum], published by the Way Out Foundation for Assistance in Solving Problems of Autism in Russia (Autizm. Druzhelyubnaya sreda [Autism. Friendly Environment, 2016).
- Fond sodeystviya resheniyu problem autizma 'Vykhod' [Way Out Foundation for Assistance in Solving Problems of Autism in Russia], 2016. Autizm. Druzhelyubnaya sreda. Kak adaptirovat prostranstvo muzeya dlya lyudey s autizmom i ikh semey [Autism: Friendly Environment. How to adapt the space of the museum for people with autism and their families] Moscow.
- Baulina, М.Е., 2016. ‘Neyropsikhologicheskaya korrektsiya vnimaniya rebyonka s sindromom Dauna: analiz sluchaya’ [Neuropsychological correction of attention in a child with Down’s syndrome: case study]. In: Klinicheskaya i meditsinskaya psikhologiya: issledovaniya, obuchenie, praktika: elektronnyy nauchnyy zhurnal [Clinical and medical psychological: studies, training and practice: an electronic scientific journal], № 1 (11). URL: medpsy.ru/climp.
- Cohen, S., 2008. Zhizn s autizmom [Life with Autism]. Moscow: Institut obshchegumanitarnykh issledovaniy [Institute of General Humanities Studies].
- Karlenko, L.A., Petrovsky, A.V. and Yaroshevskiy, M.G., eds., 1998 Kratkiy psikhologicheskiy slovar [Abridged Psychological Dictionary]. Rostov-na-Donu: Feniks.
- Lebedinskiy, V.V., 2008. Narusheniya psikhicheskogo razvitiya v detskom vozraste: ucheb. posobie dlya stud. vysh. ucheb. zavedeniy [Disorders of psychological development in childhood: textbook for higher education students]. Moscow: Akademiya Publishing Centre.
- Morozov, S.A., 2002. Detskiy autism i osnovy ego korrektsii [Childhood autism and foundations for its correction] (special course materials). Moscow: Signal Publishers.
- Njiokiktjien, C., 2018. Detskaya povedencheskaya nevrologiya [Pediatric Behavioural Neurology]. 2 vols. Vol. 2. Mosocw: Terevinf.
- Fond sodeystviya resheniyu problem autizma 'Vykhod’ v Rossii [Way Out Foundation for Assistance in Solving Problems of Autism in Russia]. URL: outfund.ru.
- The National Autistic Society. URL: autism.org.uk.
- Samopovrezhdayushchee povedenie [Self-injurious behaviour] URL: aba.nsu.ru.
- Bayo, J., CDC., 2008/2012. ‘Prevalence of autism spectrum disorders.’ Autism and Developmental Disabilities Monitoring Network, 14 Sites, United States, 2008 / MMWR. — 2012. — 61(SS03).
- Diamond, A., Barnett, W.S., Thomas, J., Munro, S., 2007. ‘Preschool Program Improves Cognitive Control.’ In: Science, Vol. 318 (5855).
- Gillingham G. Autism: handle with care!: understanding and managing behavior of children and adults with autism. — Arlington, Texas: Future Education Inc.,
- Grandin T. Thinking in Pictures. —
- Matson, J. L., Shoemaker, M., 2009. ‘Intellectual disability and its relationship to autism spectrum disorders.’ In: Research in Developmental Disabilities, Vol. 30 (6).
- Numminen, H., Service, E., Ahonen, T., Korhonen, T., Tolvanen, A., Patja, K., Ruoppila, I., 2000. ‘Working memory structure and intellectual disability.’ In: Journal of Intellectual Disability Research, Vol. 44 (5).
- Orsolini, M., Melogno, S., Latini, N., Penge, R., Conforti, S., 2015. ‘Treating verbal working memory in a boy with intellectual disability.’ In: Frontiers in Psychology, Vol. 6.
- Postorino, V., Fatta, L.M., Sanges, V., Giobagnoli, G., De Peppo, L., Vicari, S., Mazzone, L., 2016. ‘Intellectual disability in Autism Spectrum Disorder: Investigation of prevalence in an Italian sample of children and adolescents.’ In: Research in Developmental Disabilities, Vol. 48.
- Schuiringa, H., van Nieuwenhuijzen, M., Orobio de Castro, B., Matthys, W., 2017. Executive functions and processing speed in children with mild to borderline intellectual disabilities and externalizing behavior problems. In: Child Neuropsychology. A Journal on Normal and Abnormal Development in Childhood and Adolescence. Vol. 23 (4).