Opto-vestibular interaction based on nystagmometric data
Levashov, M.M.; Tumakov, A.I.
Kosmicheskaia Biologiia i Aviakosmicheskaia Meditsina 16(3): 51-55
1982
ISSN/ISBN: 0321-5040 PMID: 6980323 Document Number: 195851
Nystagmograms (270 ENG from 30 healthy children, aged 3-7 yr) were analyzed quantitatively. Measurements included the following: the velocity of the slow component of the vestibular nystagmus during caloric tests; optokinetic nystagmus in response to stimuli applied at 20 and 10.degree./s, and vestibulooptokinetic nystagmus resulting from modulation of the optokinetic nystagmus due to the inhibitory or enhancing effect of caloric stimulation. The modulation level, i.e., the change in velocity of the slow ocmponent that accompanied the transition of the optokinetic nystagmus to the vestibulo-optokinetic nystagmus, was always less than that of the vestibular nystagmus. This disagrees with the concept about algebraic summation of the reactions intensities. The modulation level showed a low correlation with the vestibular nystagmus slow component velocity and depended on the optokinetic nystagmus velocity; at 10.degree./s the inhibitory effect was smaller than the enhancing one, and at 20.degree./s the situation was the opposite. At 20.degree./s the slow component velocity was twice higher than at 10.degree./s. The parameter may reflect the level of the residual activity of the optokinetic system which is independent of vestibular afferentation.