[How useful is the intersaccadic interval analysis of vestibular nystagmus for clinical diagnostic (author's transl)].

The intersaccadic interval analysis of vestibular nystagmus was proposed by Cheng et al. in 1974. This method gives a statistical and sequential description of intersaccadic intervals. Until now there were no reports concerning the clinical diagnostic relevance of this method in vestibular disturbancies. Therefore, we checked 8 normal probands and 7 patients (3 peripheral, 3 central vestibular lesions, one congenital nystagmus). Compared to common nystagmus parameters like maximum speed of slow phase or minimum frequency normal probands showed a relatively high variability, as well as the patients - excluding congenital nystagmus. The maximum of intersaccadic intervals of the latter was very marked between 0,9 and 1,0 seconds. In the other cases the normally monomodal distributed maxima were between 0,2 and 0,6 sec. A multimodal distribution, as described by Cheng et al. in 1974, were to be found very seldomly. The comparison of intersaccadic interval analysis with the common nystagmus parameters showed, that in clinical diagnostic this method should not be too necessary. However, regarding scientific research - including mathematical models of vestibular nystagmus - the intersaccadic interval analysis could be useful.