Bilateral involvement of a single cranial nerve: analysis of 578 cases.

The author reviewed 34 years of personal experience with inpatients in a large municipal hospital to analyze the seats and causes of involvement of single pairs of cranial nerves. Among 578 cases, the sixth (n = 234) and second (211) nerves predominated, followed by the fourth (48), seventh (30), third (27), and eighth (18) cranial nerves. Trauma (99), infection (94), tumor (92), increased intracranial pressure (85), vascular disease (74), and demyelination (66) were common causes.