Symptoms and signs of autism spectrum disorders

Symptoms and signs of autism spectrum disorders

Social communication

Difficulties and delay in social interaction are often the earliest features in ASDs, but they can be subtle and easily missed. Absence of joint attention (i.e. failure to show interest, share a  focus of attention and follow gaze) is highly suggestive of ASD.
Carers may describe that the child fails to respond to their name when called repeatedly, raising the possibility of a hearing impairment. Inadequate facial expressions, including lack of social smiling and limited use of gestures, e.g. shaking head, nodding, waving, clapping, are also features. Individuals with ASD lack awareness of others feelings and the impact of their behaviour on others. Sometimes this manifests as inappropriate behaviour in a specific social context or inappropriate response to others’ emotions. There can be misinterpretation of tone of voice and facial expressions of others, leading to difficulties with peers, often combined with the failure to develop mutual sharing of interests, activities and emotions. Younger children may not seek to share enjoyment, e.g. showing a toy to a parent or pointing out objects of interest to others.
Conversely, higher functioning individuals often seek interaction with others and make attempts to socialize, but come across as socially odd. Often, social play is limited and in isolation to their peers.
Concerns may be raised when a child has failed to acquire language as expected. Some children with ASD may develop no useful communicative speech or sounds. In contrast to those with specific language disorders, children with ASD often fail to use gestures or mime to compensate. Instead, parents may describe the child either obtaining a required object themselves or taking another person’s hand to the object as if to use them as a ‘tool’. Language is often atypical with idiosyncratic use of words or phrases, e.g. nonsense or jargon words, or referral to self as ‘you’ (pronominal reversal). Other features include abnormal delivery of speech (prosody), i.e. unusual pitch, speed, volume or tone. Whatever the language skills present, two-way reciprocal conversational interchanges tend to be difficult, particularly if the topic of conversation is restricted to the narrowed/circumscribed and repetitive interest of the affected individual. An individual with ASD often struggles to engage in social chat and build on conversation about someone else’s hobby or interest.

Restricted, repetitive behaviors, interests and activities

Interests and activities in individuals with ASD are often restrictive and repetitive. Stereotyped or repetitive motor mannerisms such as hand flapping, finger flicking, head banging and twirling may be seen. Repetitive use of objects i.e.
lining up toys, and repetitive use of speech e.g. delayed echolalia or stereotyped phrases (with constant form or pattern) are well recognised. Delayed echolalia is the term applied to copied or directly imitated speech, e.g. from an adult (such as a relative or teacher, television or radio) that is repeated some time after it is originally heard. For many individuals, play may lack creativity and imagination, but isolated examples of pretend play and imitative behaviour do not exclude a diagnosis of ASD. A child may have a preoccupation with an interest that is abnormal in intensity, content or both.
Some individuals with ASD have superior or special splinter skills/abilities in one or more areas of functioning e.g. calculations, memory, music, artistic endeavours. There can be insistence on sameness such that changes in routines or environment are often resisted and not uncommonly result in  distress and/or temper tantrums. Hypo- or hyper-sensitivity to environmental stimuli or unusual interest in sensory aspects of the environment can be seen e.g. response to specific sounds or textures, insensitivity to pain, or fascination with smells, textures or colours of food or fabrics.
Repetitive behaviours are common in young children and are part of normal development. However for individuals with ASD excessive rates of repetitive behaviours can cause significant social impairment, interfere with learning new skills and contribute to levels of parental stress. For individuals with an absence of restricted, repetitive patterns of behaviour, but who have persistent difficulties in the social use of verbal and nonverbal communication which limits effective communication, social relationships and learning (not explained by low cognitive ability), a new DSM-5 diagnosis of Social (pragmatic) Communication Disorder may be considered.


Regression or a period of stasis occurs in 20-30% of cases. Regression most commonly affects language, usually at the less than 10 word stage, therefore it is most often reported from 18 to 24 months of age. Motor development is preserved, but other skills can be affected and parents may concurrently report a change in sleeping or eating habits, loss of eye contact and development of a specific interest. Signs and symptoms of ASD with regression in social communication skills in a child under 3 years is strongly associated with a diagnosis of ASD although the aetiology is not understood. Regression can occur in children with ASD above 24 months, but pre-existing development is usually atypical. Autistic regression in children over 3 years or regression in motor domains warrant careful assessment by a paediatrician or paediatric neurologist to consider neurodegenerative conditions, such as Rett syndrome and Landau Kleffner.

Learning disabilities

Historically autism was mainly recognized in individuals with severe impairment and learning disabilities (IQ less than 70.) With widening of the spectrum, comorbid learning disability is reported to affect approximately 50% of people with ASD’s. Individuals may show an unusual cognitive profile with significant discrepancies between verbal and non-verbal scores (in either direction.) However, it is important to note that for individuals with “higher” scores in either verbal or non-verbal abilities this may not reflect their social skills nor their everyday adaptive living skills which are likely to be significantly impaired.


The risk of epilepsy in ASD is increased compared with the general population and linked to lower IQ and regression, with peaks of incidence occurring at pre-school age and adolescence.
Between 18% and 29% of children with ASD are affected and any seizure type can occur. Epileptiform EEGs are common in ASD, and studies have shown that 10% of children with ASD have an epileptiform EEG without any clinical evidence of seizures. There is no evidence that these discharges have a causal relationship to ASD or that routine EEGs should be performed. Any investigation and treatment should be guided by the clinical presentation of the individual.

Psychiatric, neurodevelopmental and behavioural comorbidities

Disturbances of behaviour, attention, activity, thought, mood and emotion are common in children with ASD. Children with ASD can have any developmental, medical and mental health conditions experienced by children without ASD. Disordered sleep and food selectivity are well recognized. Mental health problems include emotional difficulties such as a range of anxiety and mood disorders and behaviours that are challenging. These behaviours that challenge can include self-injurious behaviour, oppositional defiant disorder, aggressiveness, temper tantrums and emotional lability. Co-morbidities within ASD are well recognized.
Approximately 70% of individuals meet the diagnostic criteria for at least one other disorder, highlighting the importance of identifying co-morbid mental health and behavioural problems in children and young people from across the age and ability range.
There is some suggestion that particularly in those of higher functioning, the risk for additional difficulties is increased. A list of psychiatric and neurodevelopment disorders associated with ASD is given below

>Psychiatric, behavioural and neurodevelopmental comorbidities associated with autism spectrum disorder
– Attention-deficit hyperactivity disorder (ADHD)
– Tourette syndrome/tic disorder
– Dyspraxia/developmental coordination disorder (DCD)
– Dyslexia
– Obsessiveecompulsive disorder (OCD)
– Specific phobias
– Anxiety
– Depression/mood disorder
– Sleeping difficulties
– Feeding difficulties and food selectivity
– Toileting difficulties and constipation
– Oppositional defiant disorder and conduct disorder
– Self injurious behavior

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