[Nystagmus reactions after rotatory vestibular stimulation (modified Veits extended rotation method) in patients with normal equilibrium. Part II: Directional preponderance in nystagmus reactions].

Based on the absolute values of the different nystagmus reactions, measured after having used the rotational test on 70 healthy subjects, the directional preponderance (DP) was calculated in the present study according to the equation of Jongkees and Philippszoon. It could be shown that a DP of less than +/- 30% can be regarded as a normal standard only if it refers to the summarised nystagmic reaction of the per- and first postrotatory phase (Per+PI) of the test. Depending on the different parameters (frequency, amplitude or slow phase velocity of the nystagmus reactions), higher standard values have to be accepted for the different phases of the rotational test. The differentiation between healthy persons on the one hand and patients with an acute loss of vestibular function on the other can be best achieved by evaluating the nystagmographic reactions via the amplitude. Summing up, the modified rotational test also proved to be a very sensitive method in follow-up examinations of patients with vestibular lesions to differentiate between acute and compensated or regenerated stages of the disease.