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Gaze related enhancement of hemispheric blood flow in a stroke patient
S E Nadeau1, B Crosson, R L Schwartz
1Geriatric Research, Education and Clinical Center, Department of Veterans Affairs Medical Center, University of Florida College of Medicine, Gainesville 32608-1197, USA.
Objective:
A patient with a right posterior cerebral artery territory infarction and a left superior quadrantanopia exhibited improvement on various visual tasks including Goldmann perimetry during extreme right gaze. The phenomenon was investigated by functional imaging of cerebral blood flow.
Methods:
[(99m)Tc]HMPAO SPECT was carried out while the patient gazed to the right and to the left at an 8 Hz flash stimulus.
Results:
When compared with left gaze, photic stimulation during right gaze was associated with an up to 39.8% increase in regional cerebral blood flow in the damaged right hemisphere, including Brodmann's areas 3-1-2, 7, 21, 22, 39, and 40.
Conclusions:
These gaze related alterations in function and synaptic activity suggest the engagement of a novel arousal-like mechanism that may account in part for comparable findings in patients with neglect and other disorders, and may have relevance to rehabilitation.