Introducing ice-water into the left ear of right-brain-damaged
patients attenuates unilateral neglect symptoms. By examining
EEG changes over each hemisphere during this procedure,
we were able to test a hypothesis concerning the mechanism
of cold-water calorics and the attention–arousal
hypothesis of hemispatial neglect. We present a case study
of an 83-year-old woman with a massive right-hemisphere
CVA exhibiting severe hemispatial neglect. Caloric stimulation
produced a leftward eye deviation to central position,
and a temporary partial remission of neglect symptoms.
Significant changes in EEG activation indicated a central
mechanism associated with the regularization of eye gaze.
Caloric stimulation also produced a significant interaction
between EEG frequency band and hemisphere, indicating that
while both hemispheres increased in cortical activation,
the right hemisphere increase was significantly greater.
This supports the activation–arousal hypothesis of
neglect over the mutual inhibition model. (JINS,
1997, 3, 394–402.)