[Evaluation of electronystagmographically registered spontaneous nystagmus in healthy persons].

The the exception of nystagmus of ocular origin, any spontaneous and provocation nystagmus have so far been regarded as a pathological manifestation of the vestibular system. However, in recent years the existence of a physiological spontaneous nystagmus has also been discussed. To examine this question, 150 healthy persons were subjected to the standard registration according to Frenzel and Tonndorf. The evaluation of the horizontal nystagmus registered was carried out in accordance with the specified evaluation criteria for uncertain and certain nystagmus movements by means of Frenzel arrow symbols. The results were shown graphically and separately for the individual registration position. The known phenomenon of an increased occurrence of nystagmus on decrease of inhibitory factors was confirmed. In the observation of a nystagmus in registration corresponding to the fluorescent spectacles, a definite nystagmus was registered in less than 10% of the normal subjects. In visual fixation, this number was reduced to less than 5%. The results of these registrations do not justify postulation of a physiological spontaneous nystagmus. Despite the greater frequency of a nystagmus in unilluminated and closed eyes, this term should not be adopted in medical terminology without more precise knowledge of vestibulo-ocular coupling.