Objectives: Imbalances in spatial attention are most often associated with right hemisphere brain injury. This report assessed 25 chronic left hemisphere stroke patients for attentional bias. Methods: Participants were evaluated with a computerized visual search task and a standardized neuropsychological assessment known as the Behavioral Inattention Test (BITC). Twenty age-matched controls were also tested. Results: Although little to no attentional impairment was observed on the BITC, the computerized visual search task revealed statistically significant contralesional attentional impairment in the left hemisphere stroke group. Specifically, these participants required 208 ms more viewing time, on average, to reliably detect visual targets on the right side of the display compared to detection on the left side, while controls showed a difference of only 8 ms between the two sides. Conclusions: The observation of significant leftward visuospatial bias in this chronic stroke group provides further evidence that the left hemisphere also plays a role in the balance of visual attention across space. These results have implications for left hemisphere patients who are often not screened for visuospatial problems, as well as for theories of visual attention which have primarily emphasized the role of the right hemisphere. (JINS, 2016, 22, 695–704)

In most individuals, language production and visuospatial skills are subserved predominantly by the left and right hemispheres, respectively. Functional Transcranial Doppler (fTCD) provides a noninvasive and relatively low-cost method for measuring functional lateralization. However, while the silent word generation task provides an accurate and reliable paradigm for investigating lateralization of language production, there is no comparable gold-standard method for measuring visuospatial skills. Thirty undergraduate students (19 females) completed a task of spatial memory while undergoing fTCD recording. Participants completed this task at two different time points, separated by between 26 to 155 days. The relative activation between hemispheres averaged across all participants was found to be consistent across testing sessions. This was observed at the individual level also, with a quantitative index of lateralization showing high reproducibility. These findings indicate that the use of the spatial memory task with fTCD is a robust methodology for examining laterality of visuospatial skills. (JINS, 2009, 15, 1028–1032.)

Functional imaging studies of developmental dyslexia have reported reduced task-related neural activity in the temporal and inferior parietal cortices. To examine the possible contribution of subtle anatomic deviations to these reductions, volumes were measured for the major lobes of the brain, the subcortical nuclei, cerebellum, and lateral ventricles on magnetic resonance imaging (MRI) scans from 16 right-handed dyslexic men, ages 18 to 40, and 14 matched controls, most of whom had previously undergone PET imaging. A specific decrease in tissue volume was localized to the temporal lobes and was particularly prominent on the left (p < .01). An analysis of tissue composition revealed that this reduction was primarily attributable to decreased gray matter within the left temporal lobe (p < .002). Further segmentation of the temporal lobe showed that this reduction was not confined to the superior temporal gyrus, the primary location of primary auditory cortex. Reductions of temporal lobe gray matter may reflect a regional decrease in neuronal number or neuropil, which in turn may result in reading impairment.