The core features of ASD include
- impairments in social communication,
- impairments in language and related cognitive skills, and
- behavioral and emotional challenges.
These core features are significantly influenced by developmental level of language acquisition (e.g., pre-symbolic, emerging language, and conversational language) and the severity level of the disorder. In addition to these core features, sensory and feeding challenges may also be present.
The population of individuals with ASD is heterogeneous. Individuals can have abilities ranging from significant cognitive and language impairments to above-average cognitive and language abilities (e.g., college- and career-bound). However, regardless of these differences, the core characteristics and challenges associated with ASD will have an impact on the development of critical social communication skills.
Following are signs and symptoms common to ASD. Specific areas of deficit will vary; no one individual will have every sign and symptom.
Impairments in Social Communication
Impairments in social communication include deficits in joint attention, social reciprocity, and social cognition.
Joint attention is the shared focus of two or more individuals on the same object or event.
Deficits in joint attention include
- difficulty orienting toward people in a social environment;
- limited frequency of directing another's attention to share an item or event;
- restricted range of communicative functions to seek engagement and comfort from others;
- limitations in recognizing and describing another's emotional state, intention, and perspective; and
- difficulty determining causal factors for emotional states of self and others.
Social reciprocity is the back-and-forth interaction between people, during which the behavior of each person influences the behavior of the other person.
Deficits in social reciprocity include
- difficulty initiating bids for interaction,
- problems responding to bids for interaction initiated by others,
- difficulty initiating and maintaining conversations that are sensitive to social context and the interests of others,
- limitations with maintaining turn-taking in interactions, and
- difficulty recognizing and repairing breakdowns in communication.
Social cognition refers to the mental processes involved in perceiving, attending to, remembering, thinking about, and making sense of the people in our social world (Moskowitz, 2005).
Deficits in social cognition include the following:
- Challenges in social and emotional learning, including difficulty
- understanding and regulating emotions,
- appreciating the perspective of others,
- developing prosocial goals, and
- using interpersonal skills to handle developmentally appropriate tasks
(Payton et al., 2000).
- Difficulty differentiating one's own feelings from the feelings of others, taking the perspective another person, and modifying language accordingly (i.e., theory of mind).
- Difficulty integrating diverse information to construct meaning in context (i.e., central coherence; Frith & Happé, 1994).
Impairments In Language and Related Cognitive Skills
Impairments in language and related cognitive skills include deficits in the following 7 areas:
- Delayed or impaired acquisition of words, word combinations, and syntax, including
- loss of earlier learned words,
- delayed acquisition of words representing social stimuli such as actions and people's names (initial words are often nouns and attributes), and
- use of echolalia (i.e., repetition of utterances produced by others; see ASHA's resource on
echolalia and its role in gestalt language acquisition).
- Deficits in use and understanding of nonverbal and verbal communication, including
- delayed use of facial expressions, body language, and gestures as forms of communication in the latter part of the first year of life, remaining unconventional throughout development;
- use of unconventional gestures (e.g., pulling a caregiver's hand toward an item) emerge prior to or in place of more conventional gestures (e.g., giving, pointing, and head nods/headshakes);
- limited understanding of gaze shifting, distal gestures, facial expressions, and rules of proximity and body language; and
- more delayed receptive language than expressive language.
- Vocal development deficits, including
- atypical response to caregiver's vocalizations,
- atypical vocal productions, and
- abnormal prosody once speech emerges (speech may sound robotic).
- Symbolic play deficits, including
- delayed acquisition of functional and conventional use of objects,
- repetitive, inflexible, and less sophisticated and inventive play, and
- limited cooperative play in interactive situations.
- Conversation deficits, including
- limitations in understanding and applying social norms of conversation (e.g., balanced turn-taking, vocal volume, proximity, prosody, and conversational timing;
- provision of inappropriate and unnecessary information in conversation;
- provision of too little detail in conversation;
- problems taking turns during conversation;
- difficulty initiating topics of shared interest;
- preference for topics of special interest;
- difficulties in recognizing the need for clarification;
- challenges in adequately repairing miscommunications;
- problems understanding figurative language, including idioms, multiple meanings, and sarcasm; and
- lack of or limited question asking in conversation.
- Literacy deficits, including difficulty
- reading for meaning (functional use of books),
- understanding narratives and expository text genres that require multiple perspectives (e.g., persuasive and comparative/contrastive),
- getting the main idea and summarizing, and
- providing sufficient information for the reader when writing.
- Executive functioning deficits, including
- lack of or limited flexibility,
- poor problem solving,
- poor planning and organization, and
- lack of inhibition.
Behavioral and Emotional Challenges
Behavioral and emotional challenges include
- problems dealing with changes in routine and/or changing from one activity to the next;
- problems generalizing learned skills;
- using objects in unusual ways and uncommon attachments to objects;
- difficulty sleeping;
- crying, becoming angry, or laughing for reason that are difficult to determine or at seemingly inappropriate times;
- anxiety and/or social withdrawal (possibly due to factors such as misinterpretation of social events, failure to identify salient or irrelevant information, and challenges with socialization);
- depression (possibly due to challenges with socialization);
- using early-developing and/or idiosyncratic strategies for self-regulation (e.g., chewing on clothing, rocking, hand flapping, vocal play);
- using unconventional behavioral strategies and emotional expressions (e.g., aggression, tantrums, bolting from situations);
- restricted, repetitive patterns of behavior, interests, or activities; and
- problems with self-management.
Sensory and Feeding Challenges
Sensory and feeding challenges include
- sensory modality difficulties, including over-responsiveness, under-responsiveness, or mixed responsiveness patterns to environmental sounds, smells, light, tactile stimulation, movement, visual clutter, and social stimuli (e.g., social touch, proximity of others, voices);
- preference for nonsocial stimuli leading to intense interests with sensory aspects of objects and events;
- patterns of food acceptance or rejection based on manner of presentation or food texture; and
- consumption of a smaller variety of foods than the variety consumed by other family members.
Diagnostic features of ASD are present in very young children. Most families and caregivers report observing symptoms within the first 2 years of life and typically express concern by the time the child reaches 18 months of age.
Studies of children with ASD found the following:
- Parents of children with ASD reported first noticing abnormalities in their children's development—particularly in language development and social relatedness—at about 14 months of age on average (Chawarska et al., 2007).
- Infants at risk for—and later diagnosed with—ASD showed a decline (from previous normative levels) in eye fixation within the first 2–6 months of age. This pattern was not observed in typically developing infants (Jones & Klin, 2013).
- By 12 months of age, infants at risk for—and later diagnosed with—ASD demonstrated atypical eye gaze, social smiling passivity, decreased positive affect, and delayed language (Zwaigenbaum et al., 2005).
- Children with autism used fewer joint attention gestures and behaviors as infants and toddlers (based on early home videos) than did age-matched peers who were typically developing (Watson, et al., 2013; Werner & Dawson, 2005).
- Children with autism showed subtle differences in sensory–motor and social behavior at 9 to 12 months of age (based on early home videos) when compared with typically developing peers (Baranek, 1999).
- Children with autism showed lower rates of canonical babbling and fewer speech-like vocalizations across the 6- to 24-month age range (based on early home videos) than did typically developing peers (Patten et al., 2014).
- Infants at risk for—and later diagnosed with—ASD used significantly more distress vocalizations (e.g., cries, whines, screams, and squeals) than did children who were typically developing and children who were developmentally delayed; this may reflect the difficulties that children with ASD have with emotional regulation (Plumb & Wetherby, 2013).
It is well documented that more boys than girls are diagnosed with ASD (e.g., Baio et al., 2018). Girls who do meet the diagnostic criteria for ASD during early childhood tend to have additional problems (lower cognitive ability and/or additional behavioral problems). This is not the case for boys (e.g., Dworzynski et al., 2012; Lord & Schopler, 1985).
One reason for the discrepancy in diagnosis may be that ASD traits "look different" in girls than in boys. A diagnostic bias toward characteristic ASD traits as they present in boys makes it easy to miss ASD traits as they present in girls (Dworzynski et al., 2012). In addition, girls also tend to have fewer and less unusual repetitive stereotyped behaviors than boys (Mandy et al., 2012).
The following are differences in the playground behaviors of girls and boys with ASD (Dean, Harwood, & Kasari, 2017):
Girls with ASD
- stay in closer proximity to their peers and are better able to capitalize on social opportunity,
- spend more time in joint engagement,
- spend more time talking as a primary activity, and
- appear to use compensatory behaviors to gain access into peer groups (e.g., swinging a jump rope near girls playing jump rope).
Boys with ASD
- tend to play alone rather than participating in organized games,
- spend more time alone, and
- spend more time wandering as a primary activity.
A second explanation for the discrepancy in diagnosis might be that girls without additional problems are better able to cope with similar levels of ASD traits. They may mask their social challenges by using various compensatory behaviors (Dworzynski et al., 2012; Tierney et al., 2016).
Differences in the social landscape of girls may make it easier for them to camouflage or mask their social differences. For example, the social groups that girls form on the playground are "fluid." Girls with ASD stay in close proximity to peer groups and, to an observer, look similar to typically developing girls. Most boys, on the other hand, play structured games on the playground. Boys with ASD tend to spend more time wandering and, therefore, do not appear similar to their typically developing peers (Dean et al., 2017).
There are a number of co-occurring conditions frequently identified in individuals with autism. They are not necessarily present in every person.
These co-occurring conditions include
- gastrointestinal conditions,
- sleep disorders,
- neurodevelopmental disorders such as attention deficit hyperactivity disorder (ADHD),
- psychiatric disorders, and
- immune/metabolic conditions.
For a better understanding of these conditions and the impact they have on individuals with ASD, see Interagency Autism Coordinating Committee (IACC; 2017).
Speech and language disorders can also co-occur with ASD. These include
- spoken language disorders,
- written language disorders, and
- speech sound disorders (including motor speech disorders).