Am. Bronstein et al., RECOVERY FROM BILATERAL VESTIBULAR FAILURE - IMPLICATIONS FOR VISUAL AND CERVICOOCULAR FUNCTION, Acta oto-laryngologica, 1995, pp. 405-407
We report a patient who sustained severe bilateral labyrinthine lesion
s during Streptococcus suis meningitis but considerably recovered vest
ibular function over a 7 month period. This unique case allowed us to
examine the cervico-ocular reflex (COR) and visual function at various
levels of activity of his vestibular system. The slow phase COR, elic
ited by trunk oscillation (0.2 Hz) with the head earth-stationary, was
negligible immediately after the acute vestibular loss but rose to a
gain of 0.51 one month after. Seven months later, when vestibular func
tion was improved, COR gain dropped to a gain of 0.15. Measurements of
spatial visual function during whole body oscillation in the acute st
age and after 6 months showed marked improvement which correlated enti
rely with VOR measurements in the dark and during optic fixation. This
patient also showed the unique feature that, in the acute stage, eye
movement gain and visual function were poorer during whole body motion
than during identical visual target motion. These findings suggest th
at: i) the COR may be inhibited by the presence of vestibular signals,
ii) spatial vision measurements provide accurate assessment of the pa
tient's visual blurr during head motion, and iii) the severe oscillops
ia experienced by patients in the acute stage of vestibular loss may n
ot only be due to the absence of the VOR; additional degradation in ey
e movements during head motion, perhaps arising from acutely distorted
labyrinthine signals, may also play a part.