Reproducibility of hemispheric blood flow increases during line bisectioning

Objectives: To determine if attention-related changes of hemispheric perfusion increases, as assessed by blood-flow sensitive techniques, are as reliable as language-related hemispheric perfusion increases. Methods: The reproducibility of hemispheric blood flow velocity increases during a line bisection task was assessed with functional transcranial Doppler sonography. Results: Over repeated examinations, the index of lateralization of 20 healthy subjects showed a high test-retest reproducibility (r=0.9, P<0.01). No practice effects were detected over the course of 10 re-assessments of one subject. Conclusions: Hemispheric lateralization of visuospatial attention is a robust phenomenon and can be reliably determined using perfusion sensitive measurements. Future studies should focus on investigating lesion-related reorganization of attentional processing with blood-flow sensitive techniques.