Positional vertigo.

Different forms of positional nystagmus, particularly the continuous (type I) variety, were found in 86 consecutive patients admitted to general and neurological hospitals. This series is compared with 365 patients with paroxysmal (type II) and 23 patients with type III positional nystagmus. In this series of 32 of the patients with continuous type I positional nystagmus (including 15 patients with head injury) and 18 of the patients with paroxysmal type II nystagmus were found to have central lesions.