Visual search for item- and array-centered locations in patients with left middle cerebral artery stroke

Abstract

In this study we systematically explored the impact of left hemisphere (LH) lesions on array-centered and item-centered spatial attention. We investigated 16 LH first ever stroke patients, focusing on strokes of the Middle Cerebral Artery (MCA), and 15 healthy control subjects with a parallel and serial search paradigm. None of the LH patients had a hemianopia or neglect. We systematically varied the item-centered (left- or right-side of a single item) and the array-centered position (left or right position in the search array of ten items) of critical features. Lesion sites were evaluated using MRIcro (Version 1.37; Rorden and Brett, 2000). The results show that patients had no specific problem with parallel search. In serial search patients showed a left to right gradient-like increase in response time for array-positions and they omitted more items if the critical feature was located on the right side of the items in the right half of the array. For low performing patients we found an overlapping lesion area around and anterior to the precentral sulcus (Brodmann's area 6 and 44), encompassing the frontal eye field. We conclude that LH MCA strokes may lead to search impairments in spatial attention, in particular in shifting to the right side of the visual field. Impaired rightward shifting moreover reduces the chance of detecting right-sided item features (but not left-sided). This suggests that spatial attention works with different reference frames, with spatial orientation being more basic than analyzing spatial aspects of objects.

Reduced comparison speed during visual search in late life depression

“…Aside from clinical utility in depression, visual search tests may also have clinical utility in other populations, such as early Alzheimer’s disease (Tales et al, 2011; Tales, Haworth, Nelson, Snowden, & Wilcock, 2005), Parkinson’s disease (Mannan, Hodgson, Husain, & Kennard, 2008; Uc et al, 2006), and stroke (Hildebrandt, Schutze, Ebke, Brunner-Beeg, & Eling, 2005), as well as in functionally important issues such as the assessment and remediation of driving ability (Jehkonen, Saunamaki, Alzamora, Laihosalo, & Kuikka, 2012; Lavalliere, Simoneau, Tremblay, Laurendeau, & Teasdale, 2012; Uc et al, 2006). With respect to clinical practice, few tests from experimental paradigms provide the normative data necessary for clinical interpretation, and this shortcoming will need to be addressed before experimental paradigms like visual search can become useful tools for clinical neuropsychological assessment.…”

Eye Movements Interfere With Limb Motor Control in Stroke Survivors

“…However, impaired visual search may also play a role. 9 We recently studied visual search in stroke survivors who performed the Trail Making Test (TMT), 10 a visuomotor task in which visual search guides reaching movements. 11 TMT is also a predictor of on-road driving performance that is used to determine the need for on-road evaluations after stroke.…”

Visual hemispatial neglect, re-assessed

“…Second, we wanted to determine whether the adaptive search measures reflect a dissociation previously found in fixed-parameter search studies. Specifically, patients with hemispatial neglect have shown greater difficulty finding conjunctions of features (such as a red square among red triangles and blue squares) than finding singleton features (such as a blue circle among red and yellow circles) when presented in their contralesional field (e.g., Eglin et al, 1989Eglin et al, , 1991Eglin et al, , 1994Esterman et al, 2000;Hildebrandt et al, 2005;Laeng et al, 2002;Pavlovskaya et al, 2002;Riddoch & Humphreys, 1987). b Furthermore, we focused our investigation on lateralized visual impairments in hemispatial neglect.…”