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Cranial Nerve Injuries
Injuries with TBI

Most common:
CN I (olfactory n.), CN VII (facial n.), CN VIII (vestibulocochlear n.)

Intermediately common:
CN II (optic n.), CN IV>III>VI (oculomotor nn.)

Clinical Deficits
  • CN I

    due to tearing of olfactory n. filaments in/near cribiform plate through which they traverse

    Associated with: CSF rhinorrhea, an/hyposmia, dysnosmia, parosmia, cacosmia

    In higher level patients: decreased appetite, weight loss, altered feeding pattern

  • CN VII

    vulnerable due to its long tortuous course through the temporal bone

    • Tactile sensation to parts of the external ear
    • Taste sensation to the anterior 2/3s of the tongue
    • Muscles of facial expression
    • Salivary and lacrimal glands
  • CN VII

    loss of hearing or postural vertigo and nystagmus immediately after trauma

  • CN II

    partial damage can result in scotomas, blurry vision or homonymous hemianopsia

  • References

    Elovic E, Baerga E, Galang GF, Cuccurullo SJ, Reyna M, Malone RJ. Physical Medicine and Rehabilitation Board Review. 3rd ed. New York, NY: Demos Medical; 2015. Chapter 2, Traumatic Brain Injury. P.96-146.