Cranial Nerve Testing

Excerpt

Cranial nerve (CN) testing is the physical functional assessment of the nerves arising from the brain and innervating the head, neck, and trunk. This testing is widely applicable to emergency and clinical situations and can be performed relatively quickly with equipment readily available in the hospital or ambulatory environment.

Abnormalities discovered during the examination can be valuable harbingers of neurologic pathologies such as mass lesions or disease progression requiring urgent intervention (ie, enlarging intracranial aneurysm).

CN testing is particularly useful in the continuous evaluation of unconscious patients. Patients with sequelae from neurotrauma, strokes, or intracranial pathology require frequent monitoring for worsening function or condition. Higher-level tests such as brainstem auditory evoked potentials (BAEP) typically require a referral to a tertiary care center; they can be performed if abnormalities are revealed on initial CN testing.