8 research outputs found
Visual Agnosia and Posterior Cerebral Artery Infarcts: An Anatomical-Clinical Study
Background: To evaluate systematically the cognitive deficits following posterior cerebral artery (PCA) strokes, especially agnosic visual disorders, and to study anatomical-clinical correlations. Methods and Findings: We investigated 31 patients at the chronic stage (mean duration of 29.1 months post infarct) with standardized cognitive tests. New experimental tests were used to assess visual impairments for words, faces, houses, and objects. Forty-one healthy subjects participated as controls. Brain lesions were normalized, combined, and related to occipitotemporal areas responsive to specific visual categories, including words (VWFA), faces (FFA and OFA), houses (PPA) and common objects (LOC). Lesions were located in the left hemisphere in 15 patients, in the right in 13, and bilaterally in 3. Visual field defects were found in 23 patients. Twenty patients had a visual disorder in at least one of the experimental tests (9 with faces, 10 with houses, 7 with phones, 3 with words). Six patients had a deficit just for a single category of stimulus. The regions of maximum overlap of brain lesions associated with a deficit for a given category of stimuli were contiguous to the peaks of the corresponding functional areas as identified in normal subjects. However, the strength of anatomicalclinical correlations was greater for words than for faces or houses, probably due to the stronger lateralization of the VWFA, as compared to the FFA or the PPA. Conclusions: Agnosic visual disorders following PCA infarcts are more frequent than previously reported. Dedicate
Vascular topography of strokes, and overlap of the 31 lesions.
<p>Vascular topography of strokes (left panel A), and overlap of the 31 lesions in MNI space (slices are TC z = −33, −15, −5, 4, 16, 24; right panel B).</p
Results of Old/New tests.
<p>In controls (n = 41), left stroke patients (n = 15), right stroke patients (n = 13) and bilateral stroke patients (n = 3). Error bars represent +/−1 S.E.M.</p
Results of the Array tests for faces, houses, phones and words.
<p>In controls (n = 41), left stroke patients (n = 15), right stroke patients (n = 13) and bilateral stroke patients (n = 3). Error bars represent +/−1 S.E.M.</p
Examples of stimuli for the Cambridge Memory Test with houses.
<p>Panel A shows study views of a target house. Panel B displays a test item from the <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0030433#s1" target="_blank">introduction</a>. The central image is identical to the leftmost study view in Panel A. Panel C shows an item from the novel image section (the rightmost image is the target). Panel D displays a test item from the novel images with noise section (the leftmost image is the target).</p
Examples of stimuli for the Cambridge Memory Test with phones.
<p>See legend of <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0030433#pone-0030433-g002" target="_blank">Figure 2</a>.</p
Results of Cambridge Memory tests with faces, houses and phones.
<p>In controls (n = 41), left stroke patients (n = 15), right stroke patients (n = 13) and bilateral stroke patients (n = 3). Error bars represent +/−1 S.E.M.</p