Transition of nystagmus types in unilateral labyrinthine diseases

In order to clarify changes in spontaneous and positional nystagmus which occurred during the course of peripheral labyrinthine diseases, 31 patients with Ménières disease (17 cases), aural vertigo of unknown etiology (9 cases), and sudden deafness (5 cases) were tested repeatedly using ENG. The testing of each case was made 4.8 times on the average with an average interval of 7.2 days. Twenty-four cases (77.4%) showed more than two of the following four types which are listed in serial order of occurrence: spontaneous (or direction-fixed positional) nystagmus toward the involved ear; geotropic direction-changing positional nystagmus; spontaneous (or direction-fixed positional) nystagmus toward the opposite ear; and apogeotropic direction-changing positional nystagmus. Thus, the above-mentioned order may be regarded as the uniform pattern in the nystagmus transition caused by acute unilateral labyrinthine diseases.