Elsevier

Psychiatry Research

Volume 189, Issue 2, 30 September 2011, Pages 292-298
Psychiatry Research

Visual scanpath abnormalities in 22q11.2 deletion syndrome: Is this a face specific deficit?

https://doi.org/10.1016/j.psychres.2011.06.012Get rights and content

Abstract

People with 22q11.2 deletion syndrome (22q11DS) have deficits in face emotion recognition. However, it is not known whether this is a deficit specific to faces, or represents maladaptive information processing strategies to complex stimuli in general. This study examined the specificity of face emotion processing deficits in 22q11DS by exploring recognition accuracy and visual scanpath performance to a Faces task compared to a Weather Scene task. Seventeen adolescents with 22q11DS (11 = females, age = 17.4) and 18 healthy controls (11 = females, age = 17.7) participated in the study. People with 22q11DS displayed an overall impoverished scanning strategy to face and weather stimuli alike, resulting in poorer accuracy across all stimuli for the 22q11DS participants compared to controls. While the control subjects altered their information processing in response to faces, a similar change was not present in the 22q11DS group indicating different visual scanpath strategies to identify category within each of the tasks, of which faces appear to represent a particularly difficult subcategory. To conclude, while this study indicates that people with 22q11DS have a general visual processing deficit, the lack of strategic change between tasks suggest that the 22q11DS group did not adapt to the change in stimuli content as well as the controls, indicative of cognitive inflexibility rather than a face specific deficit.

Introduction

Velocardiofacial syndrome (VCFS), also widely known as 22q11.2 deletion syndrome (22q11DS), is associated with a deletion on the long arm of chromosome 22 and is the most common microdeletion disorder with an estimated prevalence of 1 in 4,000 live births (Oscarsdottir et al., 2004). 22q11DS is characterised by cardiac and palatal anomalies, facial dysmorphology, intellectual disabilities and cognitive deficits in multiple domains including, but not limited to, memory, attention and areas related to social cognition (Gerdes et al., 1999, Scherer et al., 1999, Scherer et al., 2001, Glaser et al., 2002). Moreover, 22q11DS appear to be a risk factor for psychiatric disorders such as autism spectrum disorders (Vorstman et al., 2006), attention deficit hyperactivity disorder (Gothelf et al., 2007), affective disorders (Green et al., 2009) and schizophrenia-like psychotic disorders (Murphy et al., 1999).

Over the last decade there has been an increase in research focused on the cognitive profiles of people with 22q11DS. Specifically, there has been a growing interest in their perceptual and social cognition abilities due to the poor social functioning experienced by these individuals. One such area is face processing, and while disturbances are commonly observed in other developmental disorders including autism (Philip et al., 2010) and schizophrenia (Loughland et al., 2004) face processing have only recently been investigated in 22q11DS. In a study by Campbell and colleagues, children with 22q11DS were observed to perform not only more poorly than healthy controls (Campbell et al., 2011) but they also performed poorer than developmentally matched children with Williams syndrome (Campbell et al., 2009) on face processing tasks. This was observed across three face matching-tasks involving identity, emotional expression and gaze direction. In addition, we have recently shown that children with 22q11.2 have more difficulties with visual memory retention of faces compared to dots and to verbal memory (Campbell et al., 2010). More recently, our group has utilised visual scanpath technology to record the eye movements of individuals with 22q11DS while they view face stimuli so as to further investigate the neurocognitive strategies these individuals employ while viewing and interpreting facial information. This research showed that participants with 22q11DS, compared with healthy controls, display atypical visual scanpath patterns, characterized by fewer fixations, shorter raw scanpath length (a ‘staring’ pattern), and more fixations focused on the mouth region or to irrelevant (i.e., ears, hair) areas of the face, rather than salient facial regions (eyes). Abnormal visual scanning in the 22q11DS group was associated with poorer emotion recognition accuracy relative to the control group (Campbell et al., 2010), suggesting that more impoverished scanning is associated with greater face processing deficits. Similar patterns of visual scanning strategies have recently been reported in a related study investigating featural and configural facial processing in a sample of adolescents with 22q11DS (Glaser et al., 2010). The authors report that whilst accuracy in recognising emotions did not differ significantly between the clinical and typically developing group, the 22q11DS group spent more time fixating on the mouth region and less time fixating at the eyes. Further, evidence from functional neuroimaging studies revealed atypical neural activation to faces relative to pictures (i.e., houses) in people with 22q11DS (van Amelsvoort et al., 2006, Andersson et al., 2008).

Cumulatively, these findings suggest a face-specific, rather than a generalised deficit in visual information processing (Andersson et al., 2008). However, face processing is a complex higher-order skill that may be mediated by disturbances in other cognitive domains that may in turn be affected by the deletion of chromosome 22q11.2. For instance, research findings reveal that children with 22q11DS perform consistently poorer on visual memory tasks, in particular visual-spatial memory, compared with verbal memory (Wang et al., 2000, Bearden et al., 2001, Woodin et al., 2001, Campbell et al., 2010), with earlier work by Swillen and colleagues (Swillen et al., 1997) showing that children with 22q11DS have weaker, but not deficient, visual-perceptual skills. In addition, it has been reported that children (Campbell, 2006) and adults (Henry et al., 2002) with 22q11DS display deficits in visual discrimination of objects, especially in tasks that require the recognition of objects from unusual views. Hence, it is important to explore the possibility that the reported deficits in facial processing are not simply due to a general visual processing dysfunction.

When investigating the specificity of face emotion processing dysfunction in other groups (e.g. schizophrenia), performance accuracy on tasks using facial stimuli have been compared to performance on various non-face control stimuli. Holmes (Holmes et al., 2005) and Shin (Shin et al., 2008) used chair discrimination as a control task for emotion discrimination; while Clark et al.(2008) examined face emotion recognition abilities relative to a non-emotional landscape categorization test. Cars, scrambled cars, butterflies and hands have also been used as control stimuli to investigate the specificity of face emotion dysfunction (Allison et al., 1994a, Allison et al., 1994b, Johnston et al., 2008). However, whilst emotion recognition ability and information processing strategies (indexed using scanpaths) associated with facial processing in these groups have been well documented there remains a lack of consensus regarding the specificity of these deficits. One reason for this is the lack of appropriate control tasks, since they rarely include stimuli of similar complexity and dimensionality that also share the social relevance inherent to facial stimuli (Morrison et al., 1988, Mandal et al., 1998, Edwards et al., 2002, Marwick and Hall, 2008).

Given that efficient visual processing skills are critical for cognition and learning, and that these deficits have far reaching academic and social consequences, visual processing deficits in 22q11DS warrants further systematic investigation. The aim of the current study is to examine the specificity of face processing deficits in 22q11DS. To do this we recorded eye movements (visual scanpaths) while participants viewed complex visual stimuli, both faces and other socially relevant, non-face stimuli. For this purpose, a Weather Scene task was constructed of images depicting seven weather scenarios with three levels of task difficulty (i.e., easy, moderate and hard) (see methodology section for a description). This research will extend previous efforts by investigating for the first time the specificity of previously identified face processing anomalies in people with 22q11DS while recording concurrently the information processing strategies used to do this (using scanpaths).

Based on previous findings in other developmental disorders with social cognition impairments (i.e., schizophrenia), we expect that the 22q11DS group will display face-specific deficits, as demonstrated by differential group performance on the Faces and Weather Scene Tasks compared with typically developing controls. We predict that this differential performance will be reflected both in terms of the scanpath strategies employed (i.e., more impoverished visual scanpath performance) and in reduced recognition accuracy performance to face verse weather scene stimuli.

Section snippets

Participants

The 22q11DS group consisted of 18 adolescents (7 males, 11 females) with genetically confirmed 22q11DS, recruited through the Velo-Cardio-Facial Syndrome Foundation of New South Wales and local Hunter Area Health services. 22q11DS participants were aged between 12 and 21 years, with a mean age of 17.44 years (SD = 3.09) and a mean full scale IQ of 72.11 (SD = 12.99). The control group consisted of 17 typically developing controls that were age (mean age = 17.65 years; SD = 2.99) and gender-matched (7

Demographic data

The data analysis was conducted on 18 participants with 22q11DS and 17 control participants. Means and standard deviations of the demographic data are presented in Table 1. Independent-samples t-tests and chi square compared groups on age, gender and intellectual functioning with no difference on age (t (33) =  0.191, p = 0.85) or gender (p = 1.0). The groups differed on the measure of intellectual functioning (F(1,32) = 42.12, p < 0.001, eta squared = 0.57) with the 22q11DS group performing approximately

Discussion

This study is the first to investigate the specificity of face processing deficits compared with non-face stimuli in adolescents with 22q11DS using visual scanpath technology. Scanpaths were measured concurrently with emotion and non-face (weather scenes) recognition accuracy. Data analysis revealed that people with 22q11DS display atypical visual scanpath patterns of performance to both face emotion and non-face (weather scenes) stimuli compared to a typically developing control group.

Across

Acknowledgements

We would like to thank Gavin Cooper for all his assistance with the development of the experimental paradigm used in the current study. We would also like to thank Dr Kathryn Leadbeater for her assistance in recruitment for the current study.

Funding for the current study was obtained from the Hunter Medical Research Institute in the form of a Port-Waratah Coal Services post-doctoral fellowship and from the NMMRC in the form of an Australian Training Fellowship (455624). Infra structure support

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