Event Abstract

Relationship between perseverations and spatial short-term memory deficits in unilateral neglect.

  • 1 University of Liège, Department of Psychology: Cognition & Behaviour, Belgium
  • 2 Hôpital Pitié-Salpêtrière, INSERM URM_S 610, France

Introduction
Spatial neglect is a multicomponent syndrome characterized by an inability to orient or to respond to stimuli arising in the hemispace contralateral to a brain lesion. According to many authors, spatial neglect can be explained by an attentional deficit, and more specifically by a lateral attentional bias towards the right (magnetic attraction) and/or difficulties in disengaging attention from items to the right side. However, attentional theories are not sufficient to explain some behaviors such as revisiting and perseverations. Recently, it has been suggested that revisiting and perseveration behaviors in visual search tasks shown in parietal neglect could be related to impairments in visuo-spatial working memory (Husain et al., 2001; Malhotra et al., 2005; Malhotra, Mannan, Driver, & Husain, 2004). This hypothesis is supported by studies (1) in which a contrast is made between cancellation tasks with and without visual control, the absence of visual feedback increasing left neglect (omissions) and repeated cancellations (perseverations) towards the ipsilesional space, and (2) in which the Corsi test is administrated in a vertical way. However, Ronchi et al. (2009) did not confirm the link between impairments in spatial short-term memory and perseverations. Indeed, these authors found no correlation between perseverations in star cancellation and spatial memory performance in the Corsi test. Nevertheless, they did not use a condition without visual feedback, which is considered as involving more spatial short-term memory than a condition with visual feedback. This methodological choice could explain the lack of relationship between short-term memory and perseverations in the Ronchi et al.’s study.
The purpose of our study was to test the hypothesis of a spatial short-term memory deficit being an explanatory factor of perseverations in unilateral neglect.

Methods
We assessed twenty-three right-damaged patients suffering from left neglect. Neglect signs were evaluated with the Batterie d’Evaluation de la Négligence (BEN) (Azouvi et al., 2002). Twenty-three healthy older participants matched for age and sociocultural level served as controls.
In order to explore the relationship between perseverations and spatial short-term memory, two different tasks were administrated: a computerized version of the Corsi test and a cancellation task. All tests were computerized and presented on a touchscreen.
The subject’s spatial span corresponded to the longest sequence in which at least three out of four sequences were correctly reproduced. The cancellation task consisted of 32 “O” presented in two conditions: with (visible) and without (invisible) visual feedback. Patients were instructed to cancel out all targets only once. The number of omissions and perseverations was calculated for each participant in both conditions.

Results
Control participants performed better than neglect patients in the Corsi test; eleven neglect patients showed a deficit in spatial short-term memory.
In the cancellation tasks, Wilcoxon matched-pairs signed ranks tests highlighted that perseverations and omissions were greater in the invisible condition for each group. In this condition, neglect patients made more omissions and perseverations (all ps <.05) than control subjects, while in the visible condition there was only a significant difference for the omissions.
In the invisible condition, the correlation between spatial short-term memory and perseverations was significant in the neglect group (r=-.55). In the visible condition, spatial short-term memory correlated with both perseverations (r=-.44) and omissions (r=-.41) in neglect patients. For the control group in the invisible condition, there was a significant correlation between spatial short-term memory and omissions (r=-.47), but not with perseverations.

Discussion
These findings suggest that a spatial short-term memory deficit cannot be considered as an explanatory factor for the perseveration behavior in unilateral neglect. Indeed, while spatial short-term memory seems to be generally involved in visual search tasks (Emrich, Al-Aidroos, Pratt, & Ferber, 2010), the invisible condition (i.e., the condition without feedback) does not seem to require more spatial short-term memory than the visible condition, contrary to our expectations. Moreover, perseverations and omissions were greater in the invisible condition than in the visible one; therefore, the hypothesis of the magnetic attraction is not confirmed either. We propose that, in the invisible condition, difficulties to plan a visual search could exacerbate both omissions and perseverations, leading to recursive search towards the right side of the space and thus promote failure to explore left space. However, further investigations will be necessary to confirm this hypothesis.

References

Azouvi, P., Samuel, C., Louis-Dreyfus, A., Bernati, T., Bartolomeo, P., Beis, J.M., Chokron, S., Leclercq, M., Marchal, F., Martin, Y., De Montety, G., Olivier, S., Perennou, D., Pradat-Diehl, P., Prairial, C., Rode, G., Sieroff, E., Wiart, L., & Rousseau, M. (2002). Sensitivity of clinical and behavioral tests of spatial neglect after right hemisphere stroke. Journal of Neurology, Neurosurgery and Psychiatry, 73, 160-166.
Emrich, S.M., Al-Aidroos, Pratt, J., & Ferber, S. (2010). Finding memory in search: The effect of visual working memory load on visual search. The quarter Journal of Experimental Pychology, 63(8), 1457-1466.
Husain, M., Mannan, S., Hodgson, T., Wojciulik, E., Driver, J., & Kennard, C. (2001). Impaired spatial working memory across saccades contributes to abnormal search in parietal neglect. Brain, 124, 941-952.
Malhotra, P., Jäger, H.R., Parton, A., Greenwood, R., Playford, E.D., Brown, M.M., Driver, J., & Husain, M. (2005). Spatial working memory capacity in unilateral neglect. Brain, 128, 424-435.
Malhotra, P., Mannan, S., Driver, J., & Husain, M., (2004). Impaired spatial working memory: one component of the visual neglect syndrome? Cortex, 40, 667-676.
Ronchi, R., Posteraro, L., Fortis, P., Bricolo, E., & Vallar, G. (2009). Perseveration in left spatial neglect: Drawing and cancellation tasks. Cortex, 45, 300-312.

Keywords: Vision Disorders, neglect patients, spatial disorders, spatial memory, perseverative responses

Conference: Belgian Brain Council, Liège, Belgium, 27 Oct - 27 Oct, 2012.

Presentation Type: Poster Presentation

Topic: Higher Brain Functions in health and disease: cognition and memory

Citation: Wansard M, Bartolomeo P, Monica T, Gillet S and Meulemans T (2012). Relationship between perseverations and spatial short-term memory deficits in unilateral neglect.. Conference Abstract: Belgian Brain Council. doi: 10.3389/conf.fnhum.2012.210.00033

Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters.

The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated.

Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed.

For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions.

Received: 10 Sep 2012; Published Online: 12 Sep 2012.

* Correspondence:
Miss. Murielle Wansard, University of Liège, Department of Psychology: Cognition & Behaviour, Liège, Belgium, m.wansard@ulg.ac.be
Dr. Paolo Bartolomeo, Hôpital Pitié-Salpêtrière, INSERM URM_S 610, Paris, France, paolo.bartolomeo@gmail.com
Prof. Thierry Meulemans, University of Liège, Department of Psychology: Cognition & Behaviour, Liège, Belgium, thierry.meulemans@ulg.ac.be