Article

Little is known about the outcome and recovery mechanisms
of visual perception after a focal lesion of the occipital lobe in humans,
especially after stroke. In this study, the authors aimed to describe the
clinical course and the neural substrates of conscious perceptive visual deficit
after posterior cerebral artery infarct. The authors prospectively
included 8 patients (7 men and 1 woman; mean age, 64.6 +/- 18 years) with visual
deficit induced by partial damage of the striate cortex related to acute
posterior cerebral artery infarct. Conscious perception of color and motion was
assessed from the acute phase to the third month. Functional magnetic resonance
imaging was performed to investigate neural substrates of visual recovery.
RESULTS: In the acute phase of stroke, visual deficiency was global (3/8
patients), selective to color (4/8 patients), or selective to motion (1/8
patients). During the follow-up, visual performance increased with respect to
color (from 29% to 70%; P < .005) and with respect to motion (from 47% to 74%; P
< .005). Despite a lack of ipsilesional V1 area activation in the acute phase,
activations in this area and in the contralesional extrastriate cortex were
obtained during follow-up. Both ipsilesional and contralesional V4 activations
were correlated with better outcome. CONCLUSIONS: Extensive visual recovery
occurs early after partial acute posterior cerebral artery infarct. Spared
islands in ipsilesional V1 area and transcallosal pathways might be involved in
poststroke visual recovery.

Langue : ANGLAIS