unimodal performance that are independent of variability introduced by differences in the site and extent of lesions among patients in the sample (Caramazza & Badecker, 1989). Dissociations within a single case provide evidence for the absolute or relative separation of neural processes underlying individual performance under different test conditions (see Shallice, 1988, for a review of the logic underlying single-case methodology). In the first task, we report extinction indices that measure decrements in the detection of dual compared to single objects as a function of their egocentric location. To our knowledge, this is the first time that detection rates have been compared for vis- ual and auditory stimuli presented at identical locations in the horizontal meridian (azimuth). In the second task, sen- sitivity to temporal asynchrony between two stimuli is measured using a temporal order judgment (TOJ) task. Previous TOJ results have revealed a temporal disadvan- tage for contralesional compared to ipsilesional stimuli (Di Pellegrino et al., 1997; Eramudugolla et al., 2007; Karnath et al., 2002; Rorden et al., 1997). Our experiment extends these studies by evaluating spatiotemporal judgments using visual and auditory stimuli that are matched pre- cisely in terms of their spatial and temporal characteristics. METHOD Participants Two patients (F.D. & J.B.) were recruited from the stroke rehabilitation ward at the Queen’s Medical Centre, Nottingham. F.D. suffered a right middle cerebral artery (MCA) territory infarct resulting in low attenuation in the region of the superior right frontal lobe, caudate, and lentiform nucleus. J.B. had a hyperacute right MCA ter- ritory infarction with hyperdense right MCA branches. Hypodensity was also observed in the right insula and external capsules (radiographer’s reports). Patients were assessed within one month of hospital admission (14 and 31 days) and undertook a battery of clinical tests, includ- ing a star cancellation task, line bisection, and figure drawing from sample. Each demonstrated a pattern of visuospatial performance consistent with a clinical diag- nosis of neglect (see Table 1 for a clinical description for each patient). Both patients had intact hemifields, and pure-tone audiometry revealed hearing within the range of age-matched controls (Davis, 1995). A total of 15 age-matched controls (mean = 66 years, SD = 2.5 years) were also recruited from the Nottingham area. Controls had no history of neurological impairment NEGLECT IN VISION AND AUDITION 73 and showed no symptoms of neglect assessed using the same battery of tests as that administered to patients. All controls had intact hemifields and hearing performance within the normal range for their age (Davis, 1995). Stimuli and apparatus Visual stimuli consisted of two geometric shapes: a red circle and a blue square. Each was closed and subtended 8.3° of visual angle. Auditory stimuli were two digitally created vowel sounds: “ah” and “ee.” Vowel pairs were separated in their fundamental frequency by four semi- tones so that they could be easily segregated from one another (Culling, Summerfield, & Marshall, 1994). Vow- els were presented at 69 dB(A) on single-target trials and at 66 dB(A) on dual-target trials to reduce the sound level cues that would otherwise distinguish single- from dual- target trials. Before testing, each participant was familiar- ized with the visual and auditory stimuli to ensure they could accurately identify and discriminate them. The apparatus (see Figure 1) consisted of five small Bose Cube loudspeakers arranged horizontally at ear Figure 1. Schematic of the experimental apparatus. A projec- tor, screen, and speaker array were used to present visual and auditory stimuli to the same egocentric position. The display had five locations equally distributed in the horizontal plane and centered on the participant’s vertical midline. Visual and auditory stimuli were presented in separate blocks. TABLE 1 Patient information and clinical characteristics Patient Gender Age (years) F.D. J.B. F M 85 62 Time since stroke onset (days) Auditory screen Visual field (at 4,000 Hz; in dB) Line bisectiona magnitude deviation (%) Star cancellationb L/R omissions 31 14 Intact Intact <60 <40 7 8 16/3 26/5 Note. F = female. M = male. L = left. R = right. aLine length = 172 mm; bTotal number of targets = 27 L and 27 R.