title: Visual memory in unilateral spatial neglect: immediate recall versus delayed recognition.
abstract: Patients with unilateral spatial neglect (USN) often show impaired performance in spatial working memory tasks, apart from the difficulty retrieving "left-sided" spatial data from long-term memory, shown in the "piazza effect" by Bisiach and colleagues. This study's aim was to compare the effect of the spatial position of a visual object on immediate and delayed memory performance in USN patients. Specifically, immediate verbal recall performance, tested using a simultaneous presentation of four visual objects in four quadrants, was compared with memory in a later-provided recognition task, in which objects were individually shown at the screen center. Unlike healthy controls, USN patients showed a left-side disadvantage and a vertical bias in the immediate free recall task (69% vs. 42% recall for right- and left-sided objects, respectively). In the recognition task, the patients correctly recognized half of "old" items, and their correct rejection rate was 95.5%. Importantly, when the analysis focused on previously recalled items (in the immediate task), no statistically significant difference was found in the delayed recognition of objects according to their original quadrant of presentation. Furthermore, USN patients were able to recollect the correct original location of the recognized objects in 60% of the cases, well beyond chance level. This suggests that the memory trace formed in these cases was not only semantic but also contained a visuospatial tag. Finally, successful recognition of objects missed in recall trials points to formation of memory traces for neglected contralesional objects, which may become accessible to retrieval processes in explicit memory.
authors.affiliation: Hadassah Hebrew University Hospital, Jerusalem.
authors.forename: Elior
authors.initials: E
authors.lastname: Moreh
authors.forename: Tal Seidel
authors.initials: TS
authors.lastname: Malkinson
authors.forename: Ehud
authors.initials: E
authors.lastname: Zohary
authors.forename: Nachum
authors.initials: N
authors.lastname: Soroker
mesh_terms: D000328:Adult; D000368:Aged; D001921:Brain / Q000000981:diagnostic imaging / Q000473:pathology; D001931:Brain Mapping; D016009:Chi-Square Distribution; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006470:Hemorrhage / Q000150:complications; D006801:Humans; D008297:Male; D008569:Memory Disorders / Q000209:etiology*; D011939:Mental Recall / Q000502:physiology*; D008875:Middle Aged; D010468:Perceptual Disorders / Q000150:complications* / Q000209:etiology / Q000473:pathology; D010775:Photic Stimulation; D011859:Radiography; D021641:Recognition, Psychology / Q000502:physiology*; D020521:Stroke / Q000150:complications; D013997:Time Factors; D014706:Verbal Learning / Q000502:physiology