Hemispatial Neglect and Visual Search: A Large Scale Analysis

Visual hemispatial neglect, re-assessed

“…Some patients who scored 0 on the SS tasks showed contralesional deficits in the adaptive search tasks (5 in FS and 7 in CS, of 10 patients scoring 0 on SS). Additionally, the results from the adaptive CS task corroborated an often-reported finding that RHD produces greater spatial attention deficits than LHD (e.g., Behrmann et al, 2004;Stone et al, 1993). Although suggestive, we cannot rule out the possibility that other group differences (e.g., anatomical differences in left vs. right lesion volume, extent, or location) might underlie the differences found in CS performance.…”

“…Whether using the means of four or eight, or medians of eight staircase reversal points to calculate TPTs, statistical analyses were equivalent (Table 5). Second, performance in the adaptive visual search tasks was consistent with wellestablished fixed-measure findings in the neglect literature: CS tasks were more sensitive to lateralized deficits than were FS tasks (e.g., Behrmann et al, 2004;Eglin et al, 1991;Esterman et al, 2000). Nevertheless, to increase confidence in this conclusion, we ran another experiment matching the stimulus configuration of the feature and conjunction displays.…”

“…These paper-and-pencil tests are often standardized and are relatively easy to administer, requiring minimal equipment. For instance, line cancellation, line bisection, and visual search have played a major role in measuring and studying visual hemispatial neglect (a neurological disorder in which patients fail to attend to or make explicit use of contralesional information; e.g., Albert, 1973;Behrmann et al, 2004;Buxbaum et al, 2004;Ferber & Karnath, 2001;Halligan & Marshall, 1991). Although traditional paper-and-pencil tests are useful in assessing clinical signs, computerized testing can offer better control of stimulus parameters.…”

The role of visual saliency for the allocation of attention: Evidence from spatial neglect and hemianopia

“…However, this' 'release from extinction' is only partial and cannot be taken as evidence for entirely preserved pre-attentive mechanisms. In addition, several visual search studies observed a similar deficit for pre-attentive and attentive search in neglect (Behrmann et al, 2004;Eglin et al, 1989;Fellrath et al, 2012;Pavlovskaya et al, 2002). Thus, overall the evidence favouring a pre-attentive, in addition to a deficit of attentive processing weighs more than the evidence for a pure impairment of spatial selective attention in neglect.…”

Direction specific costs to spatial working memory from saccadic and spatial remapping

“…These findings on more clinically based tasks are further supported by experimental research using visual search paradigms. In one such study researchers found that, for neglect patients, visual search was most impoverished for displays in left visual space (Behrmann et al, 2004). Although visual search requires the use of SWM, the previously discussed study was not designed to examine the two mechanisms independently.…”