The Visual Scanning Test: a newly developed neuropsychological tool to assess and target rehabilitation of extrapersonal visual unilateral spatial neglect

Purpose Visual unilateral spatial neglect (VUSN) is a neuropsychological condition commonly experienced after stroke whereby patients are unable to attend to stimuli on the controlesional side of their space. VUSN can occur in the personal, peripersonal, and/or extrapersonal portion of patient's space. Traditional paper-and-pencil neuropsychological tests are widely used to evaluate VUSN, but they assess peripersonal VUSN. Instead, personal and extrapersonal neglect are less easily evaluated. The aim of this study was to present normative values for the Visual Scanning Test (VST), a new neuropsychological tool to quantitatively assess the extrapersonal VUSN. Methods Eighty-six healthy subjects took part in the study (61 female), with a mean age of 52.8 years (SD = 17.0) and a mean of 14.0 years of education (SD = 5.2). The VST involved a visual search for a target between similar visual distractors, projected in the far space. The test was administered twice to each participant, with an interval of 2 weeks. From the recorded data, it was possible to obtain indexes related to the reaction times and to the accuracy of the performance on the VST. Results Multiple linear regression analysis revealed that age and education significantly influenced VST-derived indexes. From the regression analysis, a correction grid for raw scores was built. Adjusted scores were then ranked, and by means of a non-parametric procedure, tolerance limits (both outer and inner one-sided) were defined. Conclusions The present study provided normative data for the VST in an Italian population useful for both clinical and research purposes.