Visuospatial asymmetry in dual‐task performance after subacute stroke

Abstract

Various authors have referred to an association between neglect and non-spatial components of attention. It has been suggested that an increase in attentional load could exacerbate neglect symptoms and reveal subtle, well-compensated neglect. In the present study, 21 RH and 22 LH subacute stroke patients and 20 controls performed a computerized single-detection task (CVRT) and a dual task (CVRT-D) combining the detection task with a driving simulation task. Omissions, reaction times (RTs) and RT asymmetries were analysed to investigate the influence of increasing attentional load on neglect symptoms. RT asymmetries were most pronounced in RH patients. Although a clear increase in RT asymmetries between CVRT and CVRT-D was observed, the amount of increase did not differ between both patient groups. Within both patient groups, correlations between RT asymmetries and ipsilesional RTs as a measure of general attention were significant in the single task but not in the dual task, indicating that increased attentional load may result in different degrees of lateralized and general attentional problems. Half of the patients with neglect on the BIT (Behavioural Inattention Test) showed increased RT asymmetries from CVRT to CVRT-D. Moreover, two LH and RH patients without neglect symptoms on the BIT and CVRT showed distinctively increased asymmetries in the CVRT-D, fostering the idea of an emergence of subtle neglect under increased attentional load. Dual-task performance may draw attention towards patients who, without obvious signs of neglect, may show visuospatial attention deficits in complex situations.

Visual Scanning Training for Neglect after Stroke with and without a Computerized Lane Tracking Dual Task

“…Patients’ performances on these tasks could be indicative for their abilities to compensate for neglect (Van Kessel et al, 2013). This raises the question whether these tasks might also be used as a training tool.…”

Hemispatial Neglect: Computer-Based Testing Allows More Sensitive Quantification of Attentional Disorders and Recovery and Might Lead to Better Evaluation of Rehabilitation

“…Overall the sensitivity of the PnP tests in the post-acute and chronic phases cannot be considered satisfactory (Azouvi et al, 2002; Deouell et al, 2005; Hasegawa et al, 2011; Bonato, 2012). Thus, whereas PnP tests may be acceptable to assess neglect at the bed-side in the acute phase (Nijboer et al, in press), at later stages computer-based tasks provide more sensitive and informative assessment, allowing to detect contralesional impairments in performance even in patients who perform normally at PnP tests (Schendel and Robertson, 2002; Deouell et al, 2005; Erez et al, 2009; Bonato, 2012; van Kessel et al, 2013). …”

“…Several other computerized tests were shown to unveil unilateral neglect (see Bonato, 2012 for review). These tests include variants of visual perimetry (Müller-Oehring et al, 2003; Nijboer et al, 2011), variants of the classic Posner-like detection tasks which can provide RTs measures for contralesional vs. ipsilesional hemispace (Bartolomeo, 1997; Nijboer et al, 2008; Rengachary et al, 2009), feature and conjunction search tasks (Erez et al, 2009), as well as tasks manipulating load (e.g., Russell et al, 2004, in press; Buxbaum et al, 2008, 2012; Dawson et al, 2008; Bellgrove et al, 2013; van Kessel, et al, 2010, 2013). These computer-based tasks are typically well tolerated by patients in the post-acute and chronic phases after a stroke, when tasks’ differential sensitivity with respect to PnP tests is maximal.…”

Novel insights in rehabilitation of neglect

“…They indicate that it is unclear at present which characteristics of VR are most important and that it is unknown whether effects can be sustained in the longer term. In neglect patients, VR has been recently applied both for diagnostic purposes (Broeren et al, 2007;Buxbaum et al, 2008Buxbaum et al, , 2012Jannink et al, 2009;Kim et al, 2010;Van Kessel et al, 2010, 2013aFordell et al, 2011;Peskine et al, 2011;Dvorkin et al, 2012) and as a rehabilitation tool (Webster et al, 2001;Castiello et al, 2004;Katz et al, 2005;Ansuini et al, 2006;Kim et al, 2007Kim et al, , 2011Smith et al, 2007;Sedda et al, 2012;Van Kessel et al, 2013b). In their review on the use of VR in the assessment and treatment of neglect, Tsirlin et al (2009) argue that an important benefit of VR technologies is that they provide rich and realistic environments with a high level of control over their parameters and thus allow for training in a safe and cost effective way.…”

“…Not eating food on the left part of the dish, bumping into obstacles on the left side, reading incomplete sentences in newspapers and ignoring objects on the left side are only a few impairments putting at risk the independence of stroke patients with left visuospatial neglect. Even without obvious signs of visuospatial neglect, stroke patients may suffer from subtle signs of neglect under increased attentional load (Bonato et al, 2010(Bonato et al, , 2013Van Kessel et al, 2013a). Moreover, visuospatial neglect is often associated with other disabling symptoms like anosognosia and somatoparaphrenia.…”