Babinski’s reflex refers to the dorsiflexion of the great toe and fanning of the other toes when the lateral aspect of the sole is stroked with a moderately sharp object. This abnormal reflex indicates corticospinal tract dysfunction.

Normal vs abnormal response:

• Negative Babinski’s reflex (normal in adults): Flexion of all toes.

• Positive Babinski’s reflex (abnormal in adults): Dorsiflexion of the great toe and fanning of the other toes. Normal in neonates and infants up to 24 months of age.

How to elicit babinski’s reflex

Stroke the lateral side of the sole with a moderately sharp object (e.g., a thumbnail or key). Observe for toe movement:

• Normal: All toes flex downward.

• Positive: Great toe dorsiflexes and the others fan out.

Clinical implications

Babinski’s reflex is a marker of corticospinal tract damage. It can be:

• Temporary: Seen postictally after seizures.

• Permanent: Associated with irreversible corticospinal damage.

• Triggered by noxious stimuli: Such as pain, noise, or mechanical stimulation.

Physical examination guidelines:

• Muscle Strength: Assess by resistance testing.

• Muscle Tone: Evaluate passive flexion/extension. Spasticity = intermittent resistance; Flaccidity = no resistance.

• Coordination: Ask for repetitive motor tasks.

• Deep Tendon Reflexes (DTRs): Strike tendons at elbow, wrist, knee, and ankle.

  • Hyperactive = exaggerated response.

  • Hypoactive = reduced or absent response.

• Sensation: Test pain sensation and proprioception in the feet.

Associated neurologic conditions and causes:

1. Amyotrophic Lateral Sclerosis (ALS):

   • Bilateral Babinski’s reflex, spasticity, hyperactive DTRs.

   • Associated with fasciculations, atrophy, weakness, impaired speech, difficulty swallowing and breathing.

2. Brain Tumor:

   • Involvement of corticospinal tract.

   • Babinski’s reflex with hyperactive DTRs, seizures, hemiparesis, headache, emotional lability.

3. Head Trauma:

   • Due to primary or secondary corticospinal injury.

   • Reflex with spasticity, incoordination, decreased LOC, abnormal pupillary responses.

4. Hepatic Encephalopathy:

   • Late-stage Babinski’s reflex with coma, hyperactive DTRs, fetor hepaticus.

5. Meningitis:

   • Bilateral reflex with fever, vomiting, nuchal rigidity, Kernig’s/Brudzinski’s signs, photophobia, stupor, coma.

6. Rabies:

   • Bilateral reflex in the excitation phase.

   • Restlessness, hydrophobia, painful swallowing, seizures, hyperactive DTRs.

7. Spinal Cord Injury:

   • After spinal shock resolves.

   • Reflex indicates corticospinal damage, with spasticity, proprioception loss, Horner’s syndrome (if cervical).

8. Spinal Cord Tumor:

   • Bilateral reflex with absent abdominal reflexes, spasticity, pain, incontinence.

9. Spinal Paralytic Poliomyelitis:

   • Reflex appears 5–7 days after fever onset.

   • Spasticity, neck resistance, Hoyne’s/Kernig’s/Brudzinski’s signs.

10. Spinal Tuberculosis:

    • Bilateral reflex with bladder incontinence, proprioception/motor loss, absent abdominal reflexes.

11. Stroke:

    • Cerebral stroke: Unilateral reflex with hemiplegia.

    • Brainstem stroke: Bilateral reflex with cranial nerve involvement.

12. Syringomyelia:

    • Reflex with atrophy, dysphagia, dysarthria, ataxia, hypo/hyperactive DTRs.

Special considerations:

• High risk of injury due to weakness, incoordination, and spasticity.

• Patient may require assistance with activities and adaptive devices.

• Environment should be hazard-free to prevent injury.

Diagnostic workup:

• CT/MRI of brain/spine.

• Angiography or myelography.

• Lumbar puncture if indicated.

Patient counseling:

• Instruct to call for help before ambulating.

• Teach use of supportive/adaptive devices.

Pediatric pointers:

• Babinski’s reflex is normal until about 18–24 months due to corticospinal immaturity.

• Persistent reflex after age 2 may indicate neurologic pathology (e.g., hydrocephalus).

References:

1. Caranci, F., Briganti, F., Cirillo, L., Leonardi, M., & Muto, M. (2013). Epidemiology and genetics of intracranial aneurysms. European Journal of Radiology, 82, 1598–1605.

2. Hetts, S. W., English, J. D., Dowd, C. F., Higashida, R. T., Scanlon, J. T., & Halbach, V. V. (2011). Pediatric intracranial aneurysms: New and enlarging aneurysms after index aneurysm treatment or observation. American Journal of Neuroradiology, 32, 2017–2022.