Visual extinction: The effect of temporal and spatial bias

Abstract

Unlike patients with neglect, neurological patients with extinction can detect a single event presented at any location. However when shown two brief near-simultaneous stimuli they only report the ipsilesional item. The question of what inter-stimulus delay leads to maximal extinction has clear clinical and theoretical implications. Di Pellegrino and colleagues (1997) report that extinction is maximal when the two stimuli are presented simultaneously, with less extinction when either item has a slight temporal lead. This finding supports traditional clinical diagnosis (which only presents simultaneous events), and is in accord with theories of extinction that entail individuation of objects (e.g., "token" accounts). In contrast, Cate and Behrmann (2002) report that extinction is maximal when the ipsilesional item is presented slightly prior to the contralesional item. This finding appears to support disengage models of attention. Our aim was to reveal whether the difference between these studies reflects different patients, or different methods. Specifically, we note that the stimuli used by Cate and Behrmann were biased both temporally (more ipsilesional first trials) and spatially (more items presented in ipsilesional field). We examined the performance of nine individuals with extinction, and found that maximal extinction was not influenced by temporal biases, but extinction was modulated by the spatial location of stimuli. This finding reconciles previous studies and offers new insight into this syndrome.

Biased temporal order judgments in chronic neglect influenced by trunk position

“…Consistent with most prior studies, we observed that individuals with spatial deficits following right hemisphere injury tend to report the right item as occurring first unless the left item has a substantial temporal lead (Baylis et al, 2002; Berberovic et al, 2004; Dukewich et al; 2012; Roberts et al, 2012; Robertson et al, 1998; Rorden et al, 1997; Rorden et al, 2009; Sinnett et al, 2007, Van der Stigchel and Nijboer, 2017). The novel discovery of this work is that this effect tends to be modulated by the position of the stimuli relative to the patient’s trunk.…”

“…Studies of the TOJ have revealed that an individual’s point of subjective simultaneity (PSS, where an observer does not reliably report one item occurring before another) can be influenced by bottom-up (reflexive) as well as top-down (strategic) attentional cues (for review see Spence and Parise, 2010) as well as visual eccentricity (Westheimer, 1983). Numerous studies have demonstrated that patients with neglect and/or extinction exhibit pathologically biased temporal order judgments (Baylis et al, 2002; Berberovic et al, 2004; Dukewich et al; 2012; Robertson et al, 1998; Rorden et al, 1997; Rorden et al, 2009; Sinnett et al, 2007) where the item on the contralesional side must be presented much earlier (typically in the order of 200ms) than the item on the ipsilesional side in order to be perceived as being simultaneously. On the other hand, neurologically healthy individuals who are accustomed to left-to-right reading tend to a subtle effect in the opposite direction, tending to perceive the left item as occurring first when confronted with two simultaneous stimuli (for review, see Pérez et al, 2011).…”

Understanding the parietal lobe syndrome from a neurophysiological and evolutionary perspective

“…Extinction is a milder residual defect in visual attention that often persists after patients have recovered from frank neglect (Adair & Barrett, 2008). In extinction, patients demonstrate a defect in attention only when two stimuli are presented in left and right visual hemifields simultaneously, in which case they fail to consciously perceive the stimulus contralateral to their lesion (Di Pellegrino et al, 1997;Mattingley et al, 1997;Rorden et al, 2009). Patients can typically detect the same contralateral stimulus if it is the only one presented.…”

Speed impairs attending on the left: comparing attentional asymmetries for neglect patients in speeded and unspeeded cueing tasks

“…Some evidence that the disengage deficit may not transfer to a TOJ task was hinted at in Di Pellegrino et al (1997). Di Pellegrino et al described a case study of a 65-year-old patient with neglect and extinction following a right-hemisphere stroke.…”