Visual information-processing impairments in deficit and nondeficit schizophrenia

Abstract

(2) and may represent a trait characteristic of the disorder (3). Attentional abnormalities have been found in unaffected relatives of persons with schizophrenia and in populations with subclinical dysfunctions thought to form part of the "schizophrenia spectrum" (3). Nevertheless, attention is not a unitary construct, and schizophrenia is most likely a heterogeneous disease; therefore it is unclear which aspects of attention are compromised in patients with schizophrenia and whether the impairment is related to a particular subgroup or symptom domain.A particular type of selective attention, covert visuospatial attention, has been studied in normal subjects and in persons with brain lesions by means of a simple reaction time task (4). In the covert visuospatial attention test, "covert" (as opposed to "overt") refers to shifts of attention in the absence of eye movements. These studies have shown that cueing attention to a visual location has consistent benefits and costs with respect to efficiency in detecting targets, depending on whether the cue accurately predicts the location of the target (i.e., is a valid cue; invalid cues orient the subject to the opposite side). Subjects with posterior parietal lesions have exhibited increased reaction times when detecting a target on the contralesional hemifield only if attention was initially cued to the ipsilesional hemifield (4). This increased cost from invalid cues, with normal benefit from valid cues, has been interpreted as an impairment in the function for disengaging covert visuospatial attention. Impairment in the two other covert visuospatial attention functions, shift and engage, have been related to midbrain lesions (5) and thalamic lesions (6), respectively. The covert visuospatial attention paradigm offers several advantages for the study of attention in schizophrenia. 1) Unlike many neuropsychological tests, it has dissectible cognitive operations (disengage, shift, engage), 2) it is thought to involve discrete neural systems, and 3) it allows for evaluation of asymmetric performance within subjects and for

Visuospatial attention in schizophrenia: Deficits in broad monitoring.

“…A replicated finding is that the RT benefit of trials with a valid cue relative to a neutral condition that does not provide information about where to attend tends to be larger in PSZ than in HCS (Gold et al, 1992; Liotti et al, 1993; Bustillo et al, 1997; Sapir et al, 2001). A recent study confirmed this phenomenon in a direct assessment using optimized task conditions (Spencer et al, 2011).…”

“…Although many of these studies focused on examining possible lateralized abnormalities (Bustillo et al, 1997; Carter, Robertson, Chaderjian, Celaya, & Nordahl, 1992; Carter, Robertson, Chaderjian, O’Shora-Celaya, & Nordahl, 1994; Gold et al, 1992; Liotti, Dazzi, & Umilta, 1993; Maruff, Hay, Malone, & Currie, 1995; Posner, Early, Reiman, Pardo, & Dhawan, 1988; Sapir, Henik, Dobrusin, & Hochman, 2001; Strauss, Novakovic, Tien, Bylsma, & Pearlson, 1991; Wigal, Swanson, & Potkin, 1997), they also provide more general clues about visuospatial selective attention mechanisms in schizophrenia. Notably, collapsed across hemifields, the reaction time (RT) difference between trials with a valid cue (i.e.…”

Turning it Upside Down: Areas of Preserved Cognitive Function in Schizophrenia

“…In other words, patients are able to use the advance information conveyed by spatial cues to allocate attentional resources to the expected target location prior to target onset. To ensure that reaction time differences between conditions reflect specific differences in functions of attentional selection rather than in general alerting effects of cues, several studies employed a neutral cue instead of a no-cue condition (e.g., Carter et al 1992, 1994, Bustillo et al 1997, Sapir et al 2001, Gouzoulis-Mayfrank et al 2004, 2007). These studies report essentially the same findings on cue usage.…”

“…The left graph presents averages across mean values reported by Bustillo et al (1997), Gold et al (1992), Oie et al (1998), Pardo et al (2000), Posner et al (1988), Wigal et al (1997), and Strauss et al (1991). These experiments include a total of 154 patients and 130 healthy controls.…”

Hyperfocusing in schizophrenia: Evidence from interactions between working memory and eye movements.

“…If PSZ had an impaired ability to focus attention, then they should exhibit a smaller difference in performance between valid and invalid trials, but this validity effect is generally unimpaired in PSZ (Gold, Fuller, Robinson, McMahon, Braun, & Luck, 2006; Gold, Hahn, Strauss, & Waltz, 2009; Hahn et al, 2012). Moreover, a widely replicated finding is that the performance benefit of valid cues relative to spatially non-predictive cues is often greater in PSZ than in HCS (Bustillo, Thaker, Buchanan, Moran, Kirkpatrack, & Carpenter, 1997; Gold, Randolph, Coppola, Carpenter, Goldberg, & Weinberger, 1992; Hahn et al, 2012; Liotti, Dazzi, & Umilta, 1993; Sapir, Henik, Dobrusin, & Hochman, 2001; Spencer, Nestor, Valdman, Niznikiewicz, Shenton, & McCarley, 2011). This finding of enhanced cue validity suggests that PSZ hyperfocus on the cued location on valid trials or fail to distribute attention effectively on neutral trials.…”