Neuropsychologia 41 (2003) 1171–1188 Patient assessment based on a theory of visual attention (TVA): subtle deficits after a right frontal-subcortical lesion Thomas Habekost ∗ , Claus Bundesen Department of Psychology, Center for Visual Cognition, University of Copenhagen, Njalsgade 90, DK-2300 Copenhagen, Denmark Received 27 September 2002; received in revised form 13 January 2003; accepted 17 January 2003 Abstract We report on a patient who complained of reduced awareness in the left visual field, but showed no visual neglect or extinction in clinical testing. By MR scanning, the brain damage was localized to the right basal ganglia, also involving structures in right frontal cortex. Using psychophysical testing and mathematical modeling based on Bundesen’s theory of visual attention [TVA; Psychol. Rev. 97 (1990) 523], the patient’s subjective experience of attentional disturbance was confirmed, and the deficit was specified into several components. At very short exposure durations, two effects were shown. The detection threshold was elevated, particularly in the left visual field, and stimuli in this side were given less attentional weight. In addition, the capacity of visual short-term memory (VSTM) was markedly reduced in both visual fields. The robustness of the test results was evaluated by bootstrap analysis. The study demonstrates the sensitivity and specificity gained by combining psychophysical testing with TVA modeling in the analysis of visual attention disorders. Extending the results of a pioneer study of parietal neglect patients by Duncan et al. [J. Exp. Psychol.: Gen. 128 (1999) 450], this study demonstrates the strength of the method in a single case, with a lesion outside parietal cortex, and only minor clinical symptoms. © 2003 Elsevier Science Ltd. All rights reserved. Keywords: Extinction; Basal ganglia; Visual short-term memory; Bootstrap 1. Introduction Most studies of visual neglect and extinction have tested patients with marked clinical deficits. In this article, we in- troduce a method capable of describing patients who have only minor attentional problems. The method is based on Bundesen’s theory of visual attention (TVA) [4–6]. TVA in- tegrates a large part of the basic experimental research on at- tention [8], and accounts for findings from diverse paradigms such as single-stimulus recognition, whole report, partial re- port, detection, and visual search. A neurophysiological in- terpretation of TVA is underway [7], and the model has been integrated with theories of memory, categorization, and ex- ecutive function [32,33]. Given its strength in the field of basic cognitive research, TVA should also be relevant to the clinical study of attention deficits. In a pioneer study, Duncan et al. [16] showed that the TVA model, in conjunction with tailored experiments, can indeed be used for accurate mea- surement of attention deficits. Duncan et al.’s choice of pa- tients was typical for a study of attentional disorders: visual neglect patients with lesions involving the right posterior ∗ Corresponding author. Tel.: +45-35-32-87-98. E-mail address: thomas.habekost@psy.ku.dk (T. Habekost). parietal cortex. Using the experimental techniques of whole and partial report, Duncan et al. was able to estimate a range of central attention parameters in the patient group. Besides demonstrating the analytic specificity of their method, Dun- can et al. also made some original observations. First, they showed that there was a large bilateral component to the sup- posedly “unilateral” neglect syndrome. The patients’ storage capacity of visual short-term memory (VSTM), as well as their rate of visual encoding, was markedly reduced in both visual fields. Second, although the patients’ sensory function was compromised, especially in the left visual field, selec- tivity for targets versus distractors was preserved. Encour- aged by these findings, Duncan et al. urged for the method’s application to other patient groups. The present study takes this request as its starting point. Our study reapplied the experimental design developed by Duncan et al. [16], but extended the scope of their in- vestigation. Instead of a group of parietal neglect patients, an in-depth study was made of a single patient with a lesion confined to frontal and subcortical structures in the brain. The patient showed no neglect in standard clinical tests, but still complained of reduced awareness of the left side. Accordingly, the aim of the study was to characterize this “subclinical” attention deficit and to explore the importance 0028-3932/03/$ – see front matter © 2003 Elsevier Science Ltd. All rights reserved. doi:10.1016/S0028-3932(03)00018-6