Primitive Reflexes: Assessment and Clinical Significance
Primitive reflexes are automatic, stereotypical responses present at birth and mediated by the brainstem. Their persistence beyond the expected age suggests neurological impairment or developmental delay.
1. High-Yield Reflex Table
| Reflex | Appears | Disappears |
|---|---|---|
| Moro Reflex | Birth | 4 months |
| Palmar Grasp | Birth | 4 months |
| Rooting Reflex | Birth | 4 months |
| Tonic Neck (Fencing) | Birth | 6 months |
| Babinski Reflex | Birth | 12–18 months |
2. Clinical Implications
- Asymmetry: If a reflex (like Moro) is absent on one side, suspect a peripheral nerve injury (e.g., Erb’s palsy, clavicle fracture) or hemiplegia.
- Persistence: Persistence beyond the expected age indicates damage to the developing frontal cortex or other CNS pathways.
- Exaggeration/Depression: Exaggerated reflexes may indicate CNS irritability or metabolic disorders (e.g., Hypocalcemia), while depressed reflexes suggest hypotonia or severe lethargy.
3. High-Yield Clinical Pearls
- Moro Reflex: The most important reflex to assess for generalized neurological integrity. Its persistence beyond 6 months is strongly suggestive of cerebral palsy.
- Parachute Reflex: This is a postural reflex, not a primitive one. It appears at 6–9 months and persists for life, signaling the beginning of protective motor development.
NEET PG Hint: Remember: The parachute reflex is the *last* one to appear and the only one that persists for life. For more high-yield pediatrics and free medical questions, visit mymedschool.org.