[Nystagmus reactions after rotatory vestibular stimulation (modified Veits long-term rotation) in patients with normal equilibrium. Part I: Absolute values of the nystagmus reactions].

In this study the nystagmographic findings of 70 healthy subjects--obtained after having used the rotatory test (modified method of Veits)--are summarised and visualised by means of easily appreciated graphs. In accordance with the recommendations of the ADANO, the test was carried out as a continuous turning of the chair, first clockwise and then counterclockwise, with an accelerating stimulus of 3 degrees/s2 and a sudden stop after a period of constant rotation with a speed of 90 degrees/s (trapezoidal stimulus). This was done for the absolute values of the following nystagmus parameters: frequency, amplitude and slow phase velocity of the nystagmus reaction. The limits of a normal nystagmus reaction are evaluated by the 5%- or 95%-percentiles on the one side and the mean values combined with the standard deviation mean value +/- 2 standard deviations on the other. It is shown that the rotatory test with its different phases enables very sensitive selection between healthy subjects and patients with an acute peripheral vestibular lesion. The intraindividual variability of the nystagmus reactions proved to be lower than that between our control persons (interindividual variability). By our method of employing the rotatory test it can be shown that the interfering phenomenon of habituation does not influence the nystagmographic results.