A 10-month-old infant consistently uses only her left hand to reach for toys and transfer objects. She has never been observed using the right hand for any purposeful activity. What does established handedness before 1 year of age suggest?

• A Normal variant, as dominance is genetically fixed from birth
• B Brachial plexus injury of the preferred arm
• C Contralateral cerebral hemispheric dysfunction such as hemiplegic cerebral palsy ✓
• D Autism spectrum disorder

Explanation

Handedness is not established before 12 months of age; consistent preference for one hand in infancy is always pathological. It indicates weakness or spasticity of the opposite side, classically contralateral hemiplegic cerebral palsy, so the neglected hand here points to a right hemisphere lesion. Erb palsy would affect one arm with a flaccid limb and asymmetrical Moro, not selective disuse with a normal limb examination.

Reference: Ghai Essential Pediatrics, 9th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.