Abstract
In the present investigation the nystagmus response during rotation with open eyes in darkness was compared with the response recorded during eye-closure. Eye-closure reduced the induced nystagmus response and in 20 out of 30 subjects the response decreased to such an extent that it was impossible to record by electronystagmography. A relation was found between vertical eyeball deviation during eye-closure and the degree of nystagmus inhibition. From the present investigation it appears that examinations of the peripheral vestibular function carried out while the subjects' eyes are closed often give misleading recordings which may result in incorrect conclusions. The best way of recording vestibular induced nystagmus, therefore, is to test the subjects with eyes open in total darkness.