Neglect is more common and severe at extreme hemoglobin levels in right hemispheric stroke

Anemia is 1 potential mechanism by which the brain receives inadequate oxygenation. The purpose of this study was to determine in acute stroke patients whether lower hemoglobin values were associated with worse hemispatial neglect.

In 203 subjects, neglect testing batteries were administered within 24 hours of admission for acute right hemispheric stroke. We analyzed the error rate on each test as well as "any neglect" (z score >or=2 on any of 3 selected tests compared with normal controls), as predicted by hemoglobin level, with adjustment for infarct size, National Institutes of Health Stroke Scale score, age, and sex.

The association between hemoglobin and neglect varied on the basis of hemoglobin level. At lower hemoglobin levels (<12 g/dL), each 1-point higher hemoglobin value was protective (adjusted odds ratio=0.56; 95% CI, 0.35 to 0.89) from having "any neglect." However, for a hemoglobin value >14 g/dL, each 1-point higher hemoglobin value was associated with higher odds of having neglect (adjusted odds ratio=1.67; 95% CI, 1.09 to 2.57). Similar relations were found for predicted error rate on the horizontal line bisection, line cancellation, and copy Ogden scene neglect tests. These relations seemed to be more pronounced in individuals who had a diffusion/perfusion mismatch.

Lower and higher hemoglobin levels were each associated with increased odds of neglect and with worse severity of neglect, independent of stroke size and severity. Higher hemoglobin values may represent dehydration or hyperviscosity. The importance of the extremes of hemoglobin in identifying individuals at risk for worse functional consequences of stroke warrants further study.