Physiological Postrotatory Nystagmus.
Nystagmus elicted by means of rotatory stimuli has been studied in 55 healthy subjects. In each case, 5 different end-velocities have been employed and each postrotatory nystagmus has been quantitatively evaluated by measuring various parameters of its quick phase. The mean values that could be considered as normal were searched for by means of a statistical study, but a great variability in the responses was found. Likewise, the responses of both labyrinths have often been rather asymmetrical. Therefore, such a functional asymmetry of the oculomotor responses, due to a variety of central factors, seems to be a serious diffculty for the practical use of postrotatory nystagmus as a clinical test. The particular meaning of the number of beats is discussed.