Autism Spectrum Disorder Diagnosis


  • Prevalence
  • Clinical Features: History and Examination
  • Diagnostic Criteria
  • Diagnostic Tools
  • Prevalence
    • Initially thought to be 1/1,000
    • Re-evaluations/ Change in definitions
      • DSM — DSM5
    • Current estimates
      • CDC 1/110
      • India
        • Overall 1.12/100
        • Rural 1.10 (0.67-1.8)
        • Urban 1.19 (0.6-2.3)


  • Comprehensive evaluation with following objectives:
    • Definitive diagnosis of ASD
    • Exclusion of conditions that may produce symptoms suggestive of ASD
    • Identification of comorbid conditions that have implications for treatment or genetic counseling
    • Determination of the child's level of functioning and profile of strengths and weaknesses

Clinical Features: History

  • Review of the developmental history, with particular attention to
    • Early social-emotional and language milestones
    • Play skills
    • Behavior, and
    • Any regression

Clinical Features

  • Core deficits
    • Emotional reciprocity
    • Communication (Verbal/ Non-verbal)
    • Lack of pretend play
    • Repetitive and restrictive behavior
    • Imagination (difficulty in the development of play and flexible thinking)

Lacks Emotional Reciprocity

  • Social interaction is rarely initiated spontaneously
  • Complete lack of attachment to parents
  • Excessive familiarity with strangers due to the absence of social inhibitions and stranger anxiety


  • Improper use of language
    • Receptive Language
      • Lacks communicative intent of others
    • Expressive language
      • Semantics absent
      • Lacks use of language/ gestures with intent to communicate
      • Poor eye contact
      • Echolalia

Gaze Avoidance and Echolalia

Clinical Features: Play

  • Abnormal Play
    • No imagination
    • No pretending
    • Prefers to play alone (Aloof in crowd)
  • Clumsy/ Stiff

Clinical Features: Stereotypies

  • Motor
    • Rocking/ jumping/ Hand flapping/ Toe Walking
  • Vocal
    • Echolalia
    • Repeating same words/ non-specific sounds

Hand Stereotypies

Toe Walking

Clinical Features:
Fixated interests/ Rituals

  • Pre-occupied with unusual objects/ parts of objects
    • Threads
    • Beads
    • Pencils
    • Spinning objects
  • Rituals
    • Lining up objects

Lines up objects

Spinning Objects/ Hand Stereotypies

Sensory Issues

  • Smelling
  • Touch
  • Insensitivity to pain

Covers Ears



  • Intellectual disability
  • Hyperactivity/ Inattention
  • Obsessive/ compulsive symptoms
  • Sleep Disorders
  • Epilepsy
  • GI disturbances (GERD/ Constipation)

Clinical Features: History

  • Chief parental concerns
  • History of possible seizures
  • Self-injury
  • Significant disturbance in eating (including pica) or sleep
  • Three generation family history specifically asking for
    • Autism/ ASD
    • Language delay
    • Intellectual disability (mental retardation)
    • Fragile X syndrome, Rett disorder, Angelman syndrome, Prader-Willi syndrome, Tuberous sclerosis complex
    • Learning and attentional disorders/ Obsessive-compulsive disorders
    • Extreme shyness, social phobia, or mutism
    • Seizures

Psychosocial History for family support

Examination: Anthropometry

  • Head Circumference
    • ~25% with isolated ASD have head circumference >97th percentile
      • May have mutations in the PTEN gene, placing them at risk for hamartomatous tumor syndromes
    • ~15% have microcephaly
      • Rule out a secondary cause that may explain microcephaly

Filipek PA et al. Neurology 2000; 55:468

  • Height and weight measurements
    • Since dietary obsessions and compulsions can result in poor weight gain or obesity


  • TS
    • Hypopigmented macules/ Adenoma sebaceum/ shagreen patch
  • Fragile X
    • Long Face/ large ears/ large tested (postpubertally)
  • Angelman syndrome
    • Ataxic gait/ broad mouth/ persistent smile/ language delay/ seizures
  • CNS
    • Examine for tone/ reflexes/ neurological deficits
    • Children with ASD can have mild hypotonia
    • Focal neurologic findings, such as asymmetry in tone or reflexes, require further neurologic evaluation and possible neuroimaging

Filipek PA et al. J Autism Dev Disord 1999; 29;439

Ancillary Testing

  • To exclude conditions that may produce symptoms of ASD
  • To identify potentially treatable conditions associated with ASD
  • To define child's particular pattern of strength and weaknesses for education planning
  • Hearing assessment
  • Developmental/ intelligence testing with separate estimates for verbal/ non-verbal skills
  • Assessment of adaptive skills to document the presence of associated intellectual disability and to help establish priorities for treatment planning

Guided by history and examination to include EEG/ Genetic testing/ Neuroimaging


  • Diagnostic Criteria
    • DSM 5
  • Diagnostic Tools
    • INCLEN
    • AIIMS Modified INDT-ASD Tool



  • DSM 5 (2013)
    • A single diagnosis replaces the sub-divisions
    • Diagnosis based on 2 areas
      • Deficits in social communication and Fixated interests
      • Repetitive behavior
    • Restriction of onset age loosened from 3years to “early developmental period”
    • New severity ranking

Diagnostic Criteria: DSM 5

  • According to the DSM-5 criteria, a diagnosis of ASD requires all of the following
  • Persistent deficits in social communication and social interaction in multiple settings; demonstrated by deficits in all three of the following (either currently or by history):
    • Social-emotional reciprocity (eg, failure of back-and-forth conversation; reduced sharing of interests, emotions)
  • Social-emotional reciprocity (e.g., failure of back-and-forth conversation; reduced sharing of interests, emotions)
  • Nonverbal communicative behaviors used for social interaction (e.g., poorly integrated verbal and nonverbal communication; abnormal eye contact or body language; poor understanding of gestures)
  • Developing, maintaining, and understanding relationships (e.g., difficulty adjusting behavior to social setting; difficulty making friends; lack of interest in peers)
  • Restricted, repetitive patterns of behavior, interests, or activities; demonstrated by ≥2 of the following (either currently or by history)
  • Stereotyped or repetitive movements, use of objects, or speech (e.g., stereotypes, echolalia, ordering toys, etc)
  • Insistence on sameness, unwavering adherence to routines, or ritualized patterns of behavior (verbal or nonverbal)
  • Highly restricted, fixated interests that are abnormal in strength or focus (e.g., preoccupation with certain objects; perseverative interests)
  • Increased or decreased response to sensory input or unusual interest in sensory aspects of the environment (e.g., adverse response to particular sounds; apparent indifference to temperature; excessive touching/smelling of objects)
  • The symptoms must impair function (e.g., social, academic)
  • The symptoms must be present in the early developmental period. However, they may become apparent only after social demands exceed limited capacity; in later life, symptoms may be masked by learned strategies
  • The symptoms are not better explained by intellectual disability or global developmental delay

American Psychiatric Association. Autism spectrum disorder. In: Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, American Psychiatric Association, Arlington, VA 2013. p.50

Diagnostic Criteria: DSM 5
Severity Level

  • Social communication/interaction
    • Level 1 ("Requiring support") – Noticeable impairment without support; difficulty initiating social interactions, atypical or unsuccessful responses to social overtures; decreased interest in social interactions; failure of back and forth conversation; attempts to make friends odd and unsuccessful
    • Level 2 ("Requiring substantial support") – Marked deficits in communication; impairments apparent even with supports; limited initiation of social interactions; reduced/abnormal response to social overtures
    • Level 3 ("Requiring very substantial support") – Severe impairments in functioning; very limited initiation of social interactions; minimal response to social overtures from others
  • Repetitive/Restricted Behavior
    • Level 1 ("Requiring support") – Behaviors significantly interfere with function; difficulty switching between activities; independence limited by problems with organization and planning
    • Level 2 ("Requiring substantial support") – Behaviors sufficiently frequent to be obvious to casual observer; behaviors interfere with function in a variety of settings; distress and/or difficulty changing focus or action
    • Level 3 ("Requiring very substantial support") – Behaviors markedly interfere with function in all spheres; extreme difficulty coping with change; great distress/difficulty changing focus or action

American Psychiatric Association. Autism spectrum disorder. In: Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, American Psychiatric Association, Arlington, VA 2013. p.50

Diagnostic Criteria: DSM 5
Other Specifiers

  • Clinicians specify the presence or absence of the following accompanying or associated conditions
    •  Intellectual impairment; to diagnose comorbid ASD and intellectual disability, social communication should be below that expected for general developmental level
    • Language impairment (eg, nonverbal, single words only, etc)
    • Known medical or genetic condition (eg, epilepsy, Rett syndrome, Down syndrome, etc) or environmental factor (eg, valproate, fetal alcohol exposure)
    • Another neurodevelopmental, mental, or behavioral disorder (eg, attention deficit hyperactivity disorder, developmental coordination disorder, etc)
    • Catatonia

American Psychiatric Association. Autism spectrum disorder. In: Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, American Psychiatric Association, Arlington, VA 2013. p.50

Diagnostic Tools

  • Tools based on the diagnostic criteria
  • Questions adapted to suit the cultural setting/ abolish language barriers

Neuro-developmental Disabilities Among Children in India: An INCLEN Study

Juneja M, Mishra D, Russell PSS, Gulati S, Deshmukh V, Tudu P, et al. INCLEN Diagnostic Tool for Autism Spectrum Disorder (INDT-ASD): development and validation. Indian Pediatr. 2014 May;51(5):359–65

Other Tools

  • Autism Behavior Checklist
    • List of 57 questions to be completed by a parent or teacher
    • The questions are divided into five categories: sensory, relating, body and object use, language, and social and self-help
    • Designed primarily to identify children with autism from a population of school-age children with severe disabilities
    • However, it has been used with children as young as three years
    • The reported sensitivity and specificity of the ABC in referral samples range from 38 to 58 percent and 76 to 97 percent, respectively

Johnson CP et al. Pediatrics 2007; 120:1183
Krug DA et al. J Child Psychol Psychiatry 1980; 21:221

  • Childhood Autism Rating Scale, Second Edition (CARS-2)
    • 15-item direct-observation instrument designed to facilitate the diagnosis of autism in children two years of age and older
    • Each of the items is scored on a four-point rating scale
    • CARS-2 is well correlated with the DSM-IV criteria and discriminates ASD from other developmental disorders better than the ABC
    • CARS-2 is intended for use by a trained clinician and takes approximately 20 to 30 minutes to administer
    • In a systematic review, the average sensitivity and specificity were 82 and 80 percent, respectively, for ASD

Filipek PA et al. J Autism Dev Disord 1999; 29:439
Rellini E et al. J Autism Dev Disord 2004; 34:703

  • Gilliam Autism Rating Scale
    • Consists of a checklist of 56 items for parents based on DSM diagnostic criteria
  • Autism Diagnostic Interview-Revised (ADI-R)
    • 2 to 3 hour clinical interview that probes for autistic symptoms
  • Autism Diagnostic Observation Schedule (ADOS)
    • Available for use in individuals age 12 months through adulthood


  • Diagnosis requires comprehensive evaluation preferably a team
  • Diagnosis is established based on DSM-5 Criteria
  • Evaluation uses tools that facilitate application of DSM-5 and establishment of diagnosis
  • Assessment should be made for primary concerns so that they can be addressed specifically

Thank You

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