Cerebral. Assessment of cognitive function does not often contribute to diagnosis of syndromes involving cranial nerve VIII. Unless there are specific issues suggested by history, this portion of the neurological examination can usually be omitted. The examination for aphasia should be undertaken if it appears that there is a discrepancy between the ability to detect sound versus the patient's ability to interpret sound. For example, an individual with cortical deafness may startle to a hand-clap but otherwise appears deaf.
Cranial Nerves. Other cranial nerves are rarely involved in processes that affect cranial nerve VIII. Corneal reflexes should be assessed when there are sensory complaints involving the face. Rarely, tumors of cranial nerve VIII grow larger than 3 cm and may compress cranial nerve V. Because cranial nerve VII travels with VIII in the IAC, the examiner should evaluate facial movement. Facial weakness is unusual even with large acoustical neuromas, however. In the brain stem, the nuclei of cranial nerves IX, X, and XI are close to that of VIII, and an assessment of the voice, palatal function, and gag may reveal unilateral weakness in certain patients. A careful oculomotor examination is crucial for detecting many subtypes of central vertigo.
Motor/Reflexes/Cerebellar/Gait. The motor examination should include assessment of power in the upper and lower extremities. The cerebellar examination should particularly focus on the assessment of upper extremity coordination. Reflexes should be checked, because asymmetry or a positive Babinski's sign may be a valuable clue to a brain stem disorder.
Sensory. When the history suggests a sensory disturbance, examination should be made of pinprick in the face and extremities. Position sense should be checked in all ataxic patients.
Autonomic Nervous System. The pupils should be also checked for Horner's syndrome (miosis, ptosis, and rarely anhydrosis), because the sympathetic system in the brain stem is at times affected with CN VIII dysfunction, particularly with vascular lesions (Wallenberg's syndrome). Blood pressure and pulse are taken with the patient standing, and if the blood pressure is low (110/70 or lower), it should be repeated with the patient lying flat. These procedures are intended to exclude orthostatic hypotension, which needs to be considered in patients with symptoms suggestive of postural vertigo or ataxia.
Neurovascular Examination. The carotid and subclavian arteries are examined by auscultation in all patients with symptoms that suggest cranial nerve VIII dysfunction.
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