Who assesses adults for Autism Spectrum Disorder (ASD) in Alberta?

Adult Autism Assessment in Alberta

In Alberta, adults seeking an autism spectrum disorder (ASD) diagnosis should be referred to a clinical geneticist or a multidisciplinary team that includes a psychologist, physician (developmental pediatrician, neurologist, or psychiatrist), and a speech/language pathologist. 1, 2

Diagnostic Process for Adults with Suspected ASD

Initial Assessment

• Primary care physicians are often the first to identify potential ASD symptoms in previously undiagnosed adults
• Screening can be conducted using validated tools such as the Autism Quotient (AQ) 3
• Common presentations in previously undiagnosed adults include:
  • Social communication difficulties
  • Restricted, repetitive behaviors or interests
  • Sensory sensitivities
  • Difficulties with perspective-taking
  • Non-verbal communication challenges 3

Referral Pathway

1. Primary Care Medical Home: Every individual with suspected ASD should have a designated primary care medical home 1
2. Clinical Genetics Consultation: A genetic consultation should be offered to all persons with suspected ASD 1
3. Multidisciplinary Assessment: After genetics consultation, a comprehensive evaluation should be conducted by a team including:
   • Psychologist
   • Physician (developmental pediatrician, neurologist, or psychiatrist)
   • Speech/language pathologist 2

Comprehensive Diagnostic Evaluation

The diagnostic assessment should include:

1. Standardized Diagnostic Tools:

   • Autism Diagnostic Observation Schedule-Second Edition (ADOS-2)
   • Autism Diagnostic Interview-Revised (ADI-R) 4, 5

2. Cognitive Assessment:

   • IQ testing
   • Assessment of working memory and processing speed (commonly affected in ASD) 1, 2

3. Language Assessment:

   • Receptive and expressive language evaluation 2

4. Adaptive Functioning:

   • Assessment of daily living skills 2

5. Genetic Testing (tiered approach):

   • High-resolution chromosomal analysis
   • DNA testing for Fragile X
   • Chromosomal microarray (diagnostic yield of 24%)
   • PTEN gene testing if head circumference >2.5 SD above mean 1, 2

Important Considerations

Comorbidities

• Up to 70% of adults with ASD have comorbid conditions 3
• Common comorbidities include:
  • Depression (20% vs 7% in general population)
  • Anxiety disorders (11% vs 5%)
  • Sleep difficulties (13% vs 5%)
  • ADHD 4

Differential Diagnosis

• Personality disorders
• Anxiety disorders
• Obsessive-compulsive disorder
• Attention deficit-hyperactivity disorder 3

Pitfalls and Caveats

• Diagnostic Overshadowing: Adult ASD may be masked by comorbid conditions, particularly anxiety and depression
• Gender Differences: ASD may present differently in women, often with better social camouflaging abilities
• Late Diagnosis Impact: Adults receiving a first-time diagnosis may need support with identity formation and understanding past difficulties 6
• Assessment Limitations: Standard diagnostic tools were primarily developed for children and may need adaptation for adult assessment 3

Follow-up After Diagnosis

After diagnosis, adults with ASD should receive:

• Genetic counseling (particularly important for those planning families) 1
• Referrals to appropriate support services
• Assessment and treatment of comorbid conditions
• Consideration of accommodations for education or employment 7

The diagnostic process should be customized to the individual's clinical situation, with periodic reevaluations as needed for those without an initially identified etiology 1.