A 5-year-old boy is evaluated for developmental concerns. He shows poor eye contact, difficulty with peer interaction, and repetitive hand flapping. His parents report he speaks in short phrases but often repeats words he has heard. Which feature best distinguishes his presentation as ASD rather than Language Disorder (Specific Language Impairment)?

Explanation

## Distinguishing ASD from Specific Language Impairment (SLI) ### Core Discriminator **Key Point:** The presence of repetitive motor stereotypies (hand flapping, spinning, lining up toys) combined with restricted interests is the key feature that distinguishes ASD from Language Disorder. While both conditions involve language deficits, only ASD includes the behavioral and interest-based abnormalities. ### Comparison Table | Feature | ASD | Specific Language Impairment (SLI) | | --- | --- | --- | | **Social communication deficit** | Qualitative (pragmatics, joint attention, theory of mind) | Quantitative (grammar, vocabulary, phonology) | | **Repetitive motor behaviors** | **Present (core feature)** | Absent | | **Restricted interests** | **Present (core feature)** | Absent | | **Peer interaction** | Actively avoided or inappropriate | Attempted but limited by language | | **Eye contact** | Reduced/absent | Usually normal | | **Language comprehension** | May be preserved; pragmatic deficits prominent | Significantly delayed | | **Echolalia** | Common and qualitative | Rare | | **Response to language therapy** | Limited without behavioral intervention | Good response to speech therapy alone | ### Clinical Distinction **Clinical Pearl:** A child with SLI has difficulty with the *form* of language (grammar, phonology, vocabulary) but typically uses language for social purposes. A child with ASD may have relatively preserved vocabulary or even advanced language in restricted areas (hyperlexia, pedantic speech) but fails to use language for social connection — they struggle with *pragmatics*. **High-Yield:** The DSM-5 specifies that if social-communication deficits are better explained by language disorder alone, ASD diagnosis should not be made. However, if repetitive behaviors and restricted interests are present *in addition to* language deficits, ASD is the correct diagnosis. ### Mnemonic **ASD = RRBI + Social Deficit:** Restricted, Repetitive Behaviors and Interests PLUS social-communication impairment. SLI = Language form deficits only. [cite:DSM-5 Diagnostic and Statistical Manual of Mental Disorders]