The influence of caloric nystagmus on flash evoked transient and steady-state potentials.
OBJECTIVE
Caloric stimulation leads to a reduction of the cerebral blood flow in the visual cortex. This reduction has been attributed to the suppression of visual input caused by nystagmus induced by caloric stimulation. We investigated the influence of caloric stimulation on transient flash and steady-state flash visual evoked potentials.


METHODS
Visual evoked potentials to 1 and 10 Hz flash stimulation were recorded in 12 normal subjects at baseline, during nystagmus induced by caloric stimulation with cold water, and after the cessation of nystagmus.


RESULTS
Neither the amplitude of the transient flash visual evoked potentials (1 Hz stimulation) nor the amplitude of the steady-state flash visual evoked potentials (10 Hz stimulation) was influenced by caloric stimulation compared to baseline.


CONCLUSIONS
The deactivation of the visual cortex by caloric stimulation does not seem to affect transient flash or steady-state flash visual evoked potentials. Reduction of cerebral blood flow in the visual cortex does not affect the processing of visual qualities (e.g., luminance and pattern).


CONCLUSIONS
Caloric stimulation does not reduce the amplitudes of transient flash or steady-state flash visual evoked potentials.
Engelhardt
Huberta
H
Department of Neurology, Klinikum Grosshadern, University of Munich, Marchioninistrasse 15, 81377 Munich, Germany.
Feddersen
Berend
B
Boetzel
Kai
K
Noachtar
Soheyl
S
D000328:Adult; D002560:Cerebrovascular Circulation / Q000502:physiology; D004569:Electroencephalography; D005074:Evoked Potentials, Visual / Q000502:physiology*; D005260:Female; D006358:Hot Temperature; D006801:Humans; D008297:Male; D009760:Nystagmus, Physiologic / Q000502:physiology*; D014793:Visual Cortex / Q000502:physiology