Normal motor development and developmental variation — formative SAQs

SAQ 1 (10 marks)

Parents of an 11-month-old say their child “never crawls” and only bottom-shuffles. Sitting is independent, tone is normal, both hands reach and transfer, and there is no skill loss. They want an MRI “to be sure.” [1] [3]

1. Place this presentation using WHO motor windows and the concept of healthy variation. (3) [1]
2. Outline your bedside motor assessment for this visit. (4) [2] [3]
3. Give your plan, including what you will and will not order today, and one safety-net. (3) [1] [5] [10]

Model answer

About 4.3% of healthy WHO cohort children never show hands-and-knees crawling; walking alone still has a wide window (8.2–17.6 months). Bottom-shuffling with good sitting, tone and hand use is often healthy variation, not automatic pathology. [1] Observe spontaneous movement first, then examine head/trunk control, transitions, locomotion style, fine motor, tone, power, reflexes, symmetry and any residual obligatory patterns; use corrected age only if preterm and early. [2] [3] Reassure with the specific window language, promote floor play, do not order MRI for isolated non-crawling with a normal exam, set a timed review of walking progress, and safety-net return for regression, asymmetry, stiff or floppy tone, or no efficient progress toward standing/walking. [1] [5] [10]

SAQ 2 (10 marks)

A term 15-month-old is not walking alone. Pull-to-stand and cruise are present. Tone, power and symmetry are normal. Caregivers report good play and no regression. Language is single words only; hearing has not been checked. [1] [3]

1. Is this child outside the WHO walking-alone window? Justify with numbers. (2) [1]
2. How do quality and multi-domain findings change your band (normal / monitor / escalate)? (4) [1] [3] [5]
3. Write a closed-loop plan for the next 8–12 weeks. (4) [2] [3] [10]

Model answer

No — WHO walking alone is roughly 8.2–17.6 months (1st–99th), so 15 months can still be inside the window if quality is good. [1] Normal tone, symmetry and cruise support a monitor band rather than automatic CP labelling; language lag and untested hearing push multi-domain surveillance and hearing check rather than pure motor reassurance alone; escalate earlier if tone, asymmetry, stiff gait quality or regression appear. [1] [3] [5] Plan: document skills against windows, arrange hearing assessment, promote supervised floor practice, book a dated recheck before the upper walking window is breached without progress, refer physiotherapy/early intervention if quality worsens or walking remains absent near/beyond the upper window, and give written safety-net triggers with an owner for follow-up. [2] [3] [10]