72 BARRETT, EDMONDSON-JONES, HALL Matelli, & Gentilucci, 1981). This has led researchers to extend models of visuospatial neglect and extinction to explain deficits in audition and touch (e.g., Pavani et al., 2004; Pavani et al., 2003). This generalization is given further support by behavioral (e.g., Driver & Spence, 1994; Spence & Driver, 1997; Spence, Lloyd, McGlone, Nicholls, & Driver, 2000), neuroanatomical (see Ghazanfar & Schroeder, 2006, for a recent review), and neuroimaging (Lewis, Beauchamp, & DeYoe, 2000; Macaluso, Frith, & Driver, 2001) evidence and further indicates that spatial location and attention play an important part in multimodal integration. Despite the above, multimodal accounts of neglect and extinction remain somewhat contentious (Golay, Hauert, Greber, Schnider, & Ptak, 2005; Sinnett, Juncadella, Rafal, Azanon, & Soto-Faraco, 2007; Spierer et al., 2007). A number of studies have found dissociations between visual and auditory attentional biases in patients diagnosed with visual neglect (De Renzi, Gentilini, & Barbieri, 1989; Soroker, Calamaro, Glicksohn, & Myslobodsky, 1997; Spierer et al., 2007; Zimmer, Lewald, & Karnath, 2003). These have been interpreted as evidence for selective damage to modality-specific mechanisms of spatial representation (e.g., De Renzi, Gentilini, & Pattachini, 1984; Soroker et al., 1997). This assertion emphasizes potential differences in the role of spatial selection in perceptual systems characterized by different coding principles (e.g., the spatiotopic visual and tonotopic auditory systems) and is consistent with evidence for modality-specific spatial cuing effects in vision and audition (McDonald & Ward, 1999; Roberts, Summerfield, & Hall, 2006). An alternative explanation is that the reported dissociations between measures of attentional bias may, in part, reflect differences in the specificity and sensitivity of the visual and auditory tests employed rather than the nature of the underlying impairment itself. Given the potential remedial utility afforded by intact auditory-spatial representation in patients with visual neglect (Golay et al., 2005), it is important to establish the degree of association between visual and auditory impairment when potential measure- ment artifacts are controlled. Much of the evidence for an association between visual and auditory attentional bias is based on tests that place different demands on performance in each modality (e.g., Pavani et al., 2004; Pavani, Meneghello, & Ladavas, 2001; Pavani et al., 2003). Neglect assessment typically utilizes clinical “pen and paper” tests that may include line bisec- tion, cancellation, and copying from sample tasks (e.g., Wilson, Cockburn, & Halligan, 1987). These are presented at the patient’s bedside, with the patient being given unlim- ited time to view the material and to make a manual response. Performance on these tasks draws heavily on vis- uomotor control (Parton et al., 2004). In contrast, auditory neglect has typically been assessed using tasks in which the patient is asked to localize briefly presented sounds and to make either a verbal or a simple manual response that is orthogonal to left and right (e.g., Pavani et al., 2003; Pinek, Duhamel, Cave, & Brouchon, 1989). Differences in task demands have also been con- founded by differences in the location to which visual and auditory stimuli are presented. Most auditory tasks have used sounds presented over headphones (Bellmann, Meuli, & Clarke, 2001; Karnath, Zimmer, & Lewald, 2002; Zimmer et al., 2003). These manipulate perceived location using binaural cues (interaural timing differ- ences, ITDs, and interaural level differences, ILDs; e.g., L. Bisiach et al., 1984; Zimmer et al., 2003) or monaural cues. A sound presented to only one ear has an infinite ILD (e.g., Sinnett et al., 2007). This produces sounds that appear to arise from an intracranial position, a loca- tion for which there is no visual counterpart (Blauert & Lindemann, 1986). Binaural cues also elicit a weak spatial percept to which even normal listeners, without training, can have difficulty orienting attention (Roberts et al., 2006). The lack of a spatial coincidence between auditory stimuli presented over headphones and visual stimuli presented in extrapersonal space means that stim- uli in either modality arise from different locations. Dif- ferences between binaural and monaural sounds can also make it difficult to distinguish between the involvement of spatial representation on one hand and the perceptive extinction of information from one ear on the other. Extinction for monaural sounds presented to the left ear and for binaural sounds lateralized to the left hemispace have also been shown to dissociate, suggesting distinct underlying neural processes in each case (Bellman et al., 2001; Spierer et al., 2007). An alternative method of sound presentation is to use head-related transfer functions. These generate virtual space by simulating the linear distortions in the magni- tude and phase spectrum of the acoustic signal on its path from the sound source to the eardrums, which are caused by shadowing, reflection, and diffraction by the head and outer ear. These filter characteristics are known to disambiguate front–back confusions and improve localization accuracy (Wenzel, Arruda, Kistler, & Wightman, 1993). Although this method improves the perception of auditory spatial location for sounds pre- sented over headphones, it is still not ideal as the sound source is rarely perceived as external unless personal- ized transfer functions are used (Wenzel et al., 1993; Wightman & Kistler, 1989). Even when these or free- field sounds have been used to assess auditory neglect in virtual or real space, comparative visual stimuli have either been absent (Bender & Diamond, 1965; Pavani, Lavadas, & Driver, 2002; Soroker et al., 1997) or not matched for egocentric location. In Eramudugolla et al.’s (2007) study, for example, visual stimuli were pre- sented at eccentricities of ±8.7° while auditory stimuli were presented at ±90° from fixation. This lack of explicit matching for location across visual and auditory tests has implications for the assessment of any multimo- dal spatial metric in neglect and makes quantitative com- parisons across sensory modalities difficult (but see Frassinetti et al., 2002, for a recent exception). The current paper presents two case studies that exam- ine the degree of correspondence between visual and audi- tory neglect and extinction using tasks carefully designed to match the extrapersonal spatial and temporal parame- ters of stimuli in each modality. Unlike group studies, the case-by-case approach allows direct comparisons of