A 15-month-old boy from Mumbai is brought to the pediatric outpatient department by his parents for developmental evaluation. The child was born at term with no significant perinatal complications. Currently, he can walk independently for short distances, climb onto low furniture, and throw a ball overhand. He points to objects of interest and says approximately 5–8 words ("mama", "papa", "dog", "ball", "no", "yes"). He enjoys playing alongside other children but does not yet engage in interactive play. When his mother leaves the room, he cries but is easily consoled when she returns. On examination, he scribbles spontaneously with a crayon and can stack two blocks. Which of the following developmental concerns would be MOST appropriate to screen for at this age if any of these milestones were delayed?

Explanation

## Developmental Screening at 15 Months ### Current Clinical Presentation This 15-month-old child demonstrates: - **Gross motor:** Independent walking, climbing (age-appropriate) - **Fine motor:** Scribbling, stacking 2 blocks (age-appropriate) - **Language:** 5–8 words (age-appropriate; 12–18 months = 10–50 words expected) - **Social-emotional:** Parallel play, separation anxiety with easy consolation (age-appropriate) - **Cognitive:** Pointing to objects, understanding simple commands ### High-Yield Screening at 15 Months **Key Point:** The 12–18 month period is a critical window for early identification of developmental delays, particularly language delay and autism spectrum disorder (ASD). Early intervention significantly improves outcomes. ### Recommended Screening Tools at 15 Months | Screening Tool | Focus | Sensitivity | When to Use | |---|---|---|---| | **M-CHAT-R/F** (Modified Checklist for Autism in Toddlers) | ASD risk factors | 85–90% | 16–30 months | | **MCDI** (MacArthur Communicative Development Inventory) | Language development | High | 8–30 months | | **DENVER-II** | Global development (motor, language, social) | Moderate | 0–6 years | | **ASQ-3** (Ages & Stages Questionnaire) | Screening across domains | Good | 1–65 months | **Clinical Pearl:** Language delay in toddlerhood is the most common early sign of both primary language disorder AND autism spectrum disorder. A child with <50 words by 24 months or <2-word phrases by 24 months requires formal speech evaluation. ### Why ASD/Language Screening Is Critical at This Age 1. **Early identification window:** 15–24 months is when ASD becomes detectable 2. **Intervention benefit:** Early behavioral therapy (ABA, speech therapy) has strongest evidence when started before age 3 3. **Language is a key marker:** Delayed language, reduced pointing, limited social reciprocity are red flags 4. **Parental concern:** Parents often first notice language or social differences at 12–18 months **Mnemonic: RED FLAGS for ASD at 15–24 months** — **SOCIAL** - **S**peech delay (< 10 words by 18 months) - **O**ver-focused interests (spinning, lining up toys) - **C**ommunication: reduced pointing, joint attention - **I**nteraction: prefers solitary play, no interest in peers - **A**bnormal sensory responses (covers ears, hand flapping) - **L**imited imitation or pretend play ### Why Other Options Are Incorrect Congenital heart disease, chronic kidney disease, and GERD are not developmental screening concerns at this age—they are organic medical conditions with different clinical presentations and diagnostic approaches. [cite:IAP Textbook of Pediatrics 12e Ch 2, American Academy of Pediatrics Bright Futures Guidelines]