Visuospatial working memory in children and adolescents with 22q11.2 deletion syndrome; an fMRI study

22q11.2 deletion syndrome (22q11DS) is a genetic disorder associated with a microdeletion of chromosome 22q11. In addition to high rates of neuropsychiatric disorders such as schizophrenia and attention deficit hyperactivity disorder, children with 22q11DS have a specific neuropsychological profile with particular deficits in visuospatial and working memory. However, the neurobiological substrate underlying these deficits is poorly understood. We investigated brain function during a visuospatial working memory (SWM) task in eight children with 22q11DS and 13 healthy controls, using fMRI. Both groups showed task-related activation in dorsolateral prefrontal cortex (DLPFC) and bilateral parietal association cortices. Controls activated parietal and occipital regions significantly more than those with 22q11DS but there was no significant between-group difference in DLPFC. In addition, while controls had a significant age-related increase in the activation of posterior brain regions and an age-related decrease in anterior regions, the 22q11DS children showed the opposite pattern. Genetically determined differences in the development of specific brain systems may underpin the cognitive deficits in 22q11DS, and may contribute to the later development of neuropsychiatric disorders.     

A comparative study of the neuropsychiatric and neurocognitive phenotype in two microdeletion syndromes: Velocardiofacial (22q11.2 deletion) and Williams (7q11.23 deletion) syndromes

Purpose22q11.2 deletion syndrome (22q11.2DS) and Williams syndrome (WS) are common neurogenetic microdeletion syndromes. The aim of the present study was to compare the neuropsychiatric and neurocognitive phenotypes of 22q11.2DS and WS.MethodsForty-five individuals with 22q11.2DS, 24 with WS, 22 with idiopathic developmental disability (DD) and 22 typically developing (TD) controls were compared for the rates of psychiatric disorders as well as cognitive executive and visuospatial functions.ResultsWe found that while anxiety, mood and disruptive disorders had an equally high prevalence among individuals with 22q11.2DS, WS and DDs, the 22q11.2DS group had the highest rates of psychotic disorders and the WS group had the highest rates of specific phobia. We also found that the WS group demonstrated more severe impairments in both executive and visuospatial functions than the other groups. WS and 22q11.2DS subjects had worse Performance-IQ than Verbal-IQ, a feature typical of non-verbal learning disorders.ConclusionThese findings offer a wide perspective on unique versus common phenotypes in 22q11.2DS and WS.     

Atypical developmental trajectory of functionally significant cortical areas in children with chromosome 22q11.2 deletion syndrome

Chromosome 22q11.2 deletion syndrome (22q11.2DS) is a neurogenetic disorder associated with neurocognitive impairments. This article focuses on the cortical gyrification changes that are associated with the genetic disorder in 6-15-year-old children with 22q11.2DS, when compared with a group of age-matched typically developing (TD) children. Local gyrification index (lGI; Schaer et al. [2008]: IEEE Trans Med Imaging 27:161-170) was used to characterize the cortical gyrification at each vertex of the pial surface. Vertex-wise statistical analysis of lGI differences between the two groups revealed cortical areas of significant reduction in cortical gyrification in children with 22q11.2DS, which were mainly distributed along the medial aspect of each hemisphere. To gain further insight into the developmental trajectory of the cortical gyrification, we examined age as a factor in lGI changes over the 6-15 years of development, within and across the two groups of children. Our primary results pertaining to the developmental trajectory of cortical gyrification revealed cortical regions where the change in lGI over the 6-15 years of age was significantly modulated by diagnosis, implying an atypical development of cortical gyrification in children with 22q11.2DS, when compared with the TD children. Significantly, these cortical areas included parietal structures that are associated, in typical individuals, with visuospatial, attentional, and numerical cognition tasks in which children with 22q11.2DS show impairments.     

Shyness discriminates between children with 22q11.2 deletion syndrome and Williams syndrome and predicts emergence of psychosis in 22q11.2 deletion syndrome

Background

22q11.2 deletion syndrome (22q11.2DS) is a common neurogenetic syndrome associated with high rates of psychosis. The aims of the present study were to identify the unique temperament traits that characterize children with 22q11.2DS compared to children with Williams syndrome (WS) and typically developing (TD) controls, and to examine temperamental predictors of the emergence of psychosis in 22q11.2DS.

Methods

The temperament of 55 children with 22q11.2DS, 36 with WS, and 280 TD children was assessed using the Emotionality, Activity, Sociability (EAS) Temperament Survey, Parental Ratings. The presence of a psychotic disorder was evaluated in 49 children and adolescents with 22q11.2DS at baseline and again 5.43 ± 2.23 years after baseline temperament assessment.

Results

Children with 22q11.2DS scored higher on Shyness compared to WS and TD controls. Children with 22q11.2DS and WS scored higher on Emotionality and lower on Activity compared to TD controls. Shyness was more severe in older compared to younger children with 22q11.2DS. Baseline Shyness scores significantly predicted the later emergence of a psychotic disorder at follow-up, in children with 22q11.2DS.

Conclusions

Our results suggest that shyness is an early marker associated with the later emergence of psychosis in 22q11.2DS.     

How might stress contribute to increased risk for schizophrenia in children with chromosome 22q11.2 deletion syndrome?

The most common human microdeletion occurs at chromosome 22q11.2. The associated syndrome (22q11.2DS) has a complex and variable phenotype with a high risk of schizophrenia. While the role of stress in the etiopathology of schizophrenia has been under investigation for over 30 years (Walker et al. 2008), the stress–diathesis model has yet to be investigated in children with 22q11.2DS. Children with 22q11.2DS face serious medical, behavioral, and socioemotional challenges from infancy into adulthood. Chronic stress elevates glucocorticoids, decreases immunocompetence, negatively impacts brain development and function, and is associated with psychiatric illness in adulthood. Drawing knowledge from the extant and well-developed anxiety and stress literature will provide invaluable insight into the complex etiopathology of schizophrenia in people with 22q11.2DS while suggesting possible early interventions. Childhood anxiety is treatable and stress coping skills can be developed thereby improving quality of life in the short-term and potentially mitigating the risk of developing psychosis.     

Increased incidence and size of cavum septum pellucidum in children with chromosome 22q11.2 deletion syndrome

Chromosome 22q11.2 deletion syndrome (22q11.2DS) is a result of a hemizygotic microdeletion that results in a variety of impairments in children including greater risk for psychiatric ailments in adulthood. We used high-resolution magnetic resonance imaging to accurately quantify the length and, for the first time, volume, of the cavum septum pellucidum (CSP) in children aged 7 to 14 years with 22q11.2DS and typically developing (TD) controls. Significantly greater anteroposterior length and greater CSP volumes were found in children with 22q11.2DS compared with controls. Furthermore, the largest CSP were found only in the 22q11.2DS group and with a much higher incidence than previously reported in the literature. Given the significant midline anomalies in the brains of those affected by 22q11.2DS, large CSP may be a biomarker of atypical brain development. The implication of these larger CSP for cognitive and behavioral development is a topic in need of further investigation.     

Approximate additions and working memory in individuals with Down syndrome

There is some evidence that individuals with Down syndrome (DS) may have a poorer mathematical performance and a poorer working memory (WM) than typically developing (TD) children of the same mental age. In both typical and atypical individuals, different aspects of arithmetic and their relationships with WM have been largely studied, but the specific contribution of WM to the representation and elaboration of non-symbolic quantities has received little attention. The present study examined whether individuals with DS are as capable as TD children matched for fluid intelligence of estimating numerosity both of single sets and of added sets resulting when two sequentially presented sets are added together, also considering how these tasks related to verbal and visuospatial WM. Results showed that the DS group's performance was significantly worse than the TD group's in numerosity estimation involving one set, but not when estimating the numerosity resulting from the addition. Success in the addition task was related to success in the working memory tasks, but only for the group with DS; this applied especially to the visuospatial component, which (unlike the verbal component) was not impaired in the group with DS. It is concluded that the two numerosity tasks involve different processes. It is concluded that the arithmetical and working memory difficulties of individuals with DS are not general, and they can draw on their WM resources when estimating the numerosity of additions.     

Relationship between reaction time, fine motor control, and visual-spatial perception on vigilance and visual-motor tasks in 22q11.2 Deletion Syndrome

22q11.2 Deletion Syndrome (22q11DS) is a common microdeletion disorder associated with mild to moderate intellectual disability and specific neurocognitive deficits, particularly in visual-motor and attentional abilities. Currently there is evidence that the visual-motor profile of 22q11DS is not entirely mediated by intellectual disability and that these individuals have specific deficits in visual-motor integration. However, the extent to which attentional deficits, such as vigilance, influence impairments on visual motor tasks in 22q11DS is unclear. This study examines visual-motor abilities and reaction time using a range of standardised tests in 35 children with 22q11DS, 26 age-matched typically developing (TD) sibling controls and 17 low-IQ community controls. Statistically significant deficits were observed in the 22q11DS group compared to both low-IQ and TD control groups on a timed fine motor control and accuracy task. The 22q11DS group performed significantly better than the low-IQ control group on an untimed drawing task and were equivalent to the TD control group on point accuracy and simple reaction time tests. Results suggest that visual motor deficits in 22q11DS are primarily attributable to deficits in psychomotor speed which becomes apparent when tasks are timed versus untimed. Moreover, the integration of visual and motor information may be intact and, indeed, represent a relative strength in 22q11DS when there are no time constraints imposed. While this may have significant implications for cognitive remediation strategies for children with 22q11DS, the relationship between reaction time, visual reasoning, cognitive complexity, fine motor speed and accuracy, and graphomotor ability on visual-motor tasks is still unclear.     

Psychiatric disorders in people with 22q11.2 Deletion Syndrome: A population‐based prevalence study in Ireland

Background : 22q11.2 Deletion Syndrome (22q11.2 DS) is a common micro‐deletion syndrome associated with intellectual disability, brain abnormalities and a complex spectrum of psychiatric disorders in both adults and children. Many previous studies have shown that adults with 22q11.2 DS have approximately thirty times greater risk for the developing schizophrenia compared to the general population. Furthermore, studies of children and adolescents with 22q11.2 DS have found high rates of psychotic symptoms, ADHD and anxiety disorders. In this study we initially aim to characterize the psychiatric and neuropsychological phenotype of all individuals in Ireland with 22q11.2 DS and then correlate our findings with genetic association studies and brain imaging. We then intend to undertake a longitudinal study to assess for risk factors of future psychotic illness. Methods : Forty‐four individuals with 22q11.2 DS (Mean age = 14 years, SD = 9) were compared to 25 non‐affected sibling controls (Mean age = 12 years, SD = 4). Psychiatric phenotype assessment was performed using a range of standardized clinical assessments including, the Diagnostic Interview Schedule for Children (DISC), Psychotic Supplement of K‐SADS, Comprehensive Assessment of At Risk Mental State (CAARMS), the Schedule for Clinical Assessment in Neuropsychiatry (SCAN), Child Behaviour Checklist (CBCL) and the Social Communication Questionnaire (SCQ). Results : Preliminary data indicates that individuals in the 22q11.2 DS group have a higher prevalence of psychiatric disorders including; ADHD (41%), psychotic symptoms (19%), schizophrenia (2.7%), specific phobias (38%), depressive episodes (11%), and anxiety disorders (32%). Conclusion : This is the first stage in a longitudinal follow‐up study of individuals with 22q11.2DS in Ireland. Our preliminary results are consistent with previous findings of high rates of psychiatric disorders in people with 22q11.2DS. The challenge remains to identify precursor symptoms in childhood that predicts the later development of psychiatric disorders, particularly schizophrenia in this vulnerable group.     

Face processing in 22q11.2 deletion syndrome: atypical development and visual scanning alterations

Background

Previous research links social difficulties to atypical face exploration in 22q11.2 deletion syndrome (22q11.2DS). Two types of face processing are distinguished: configural (CFP) and featural (FFP). CFP develops later in life and plays an important role in face and emotion recognition abilities. Recent studies reported atypical development of CFP in several neurodevelopmental disorders. Taking previous reports of atypical face exploration one step further, our study aims at characterizing face processing in children and adolescents with 22q11.2DS. First, we sought to identify biases in the first two fixation positions on faces and to detect differences between CFP and FFP in 22q11.2DS using eye-tracking technology. Second, we investigated the developmental trajectories of CFP and FFP using accuracy data from follow-up evaluation.

Methods

Seventy-five individuals with 22q11.2DS and 84 typically developed (TD) individuals (aged 6–21 years) completed a discrimination task (“Jane task”) inducing CFP and FFP in an eye-tracking setting. Thirty-six individuals with 22q11DS and 30 TD from our sample completed a longitudinal follow-up evaluation.

Results

Findings revealed that individuals with 22q11.2DS demonstrate an early bias toward the mouth region during the initial fixations on the faces and reduced flexibility exploration of the faces, with a reduced number of transitions between faces and longer fixations compared to the TD group. Further, scanpaths did not differ between CFP and FFP in the 22q11.2DS group. Longitudinal analysis of accuracy data provided evidence for atypical development of CFP in 22q11.2DS.

Conclusions

The current study brings new evidence of altered face exploration in 22q11.2DS and identifies developmental mechanisms that may contribute to difficulties impacting social interactions in the syndrome.

     

No evidence for an effect of COMT Val158Met genotype on executive function in patients with 22q11 deletion syndrome

OBJECTIVE: Previous studies linking the catechol O-methyltransferase (COMT) functional polymorphism to the specific phenotype in 22q11.2 deletion syndrome (22q11.2DS) have yielded inconsistent results. The goal of the present study was to replicate a recent finding that executive function is higher in individuals hemizygous for the Met allele. METHOD: Thirty-four children and young adults with a 22q11.2 microdeletion, hemizygous for the Val (N=14) or Met (N=20) polymorphism, were tested on measures of executive function, IQ, and memory. RESULTS: No significant differences were detected between Met- and Val-hemizygous participants on measures of executive function. The groups did not differ on full-scale, performance, and verbal IQ or on verbal and visual memory. CONCLUSIONS: These results suggest either a small effect of the COMT polymorphism on executive function in 22q11.2DS or no effect at all. Further research is needed to characterize the implications of hemizygosity of COMT in 22q11.2DS for cognitive function.     

Visual memory profile in 22q11.2 microdeletion syndrome: are there differences in performance and neurobiological substrates between tasks linked to ventral and dorsal visual brain structures? A cross-sectional and longitudinal study

Background

Children affected by the 22q11.2 deletion syndrome (22q11.2DS) have a specific neuropsychological profile with strengths and weaknesses in several cognitive domains. Specifically, previous evidence has shown that patients with 22q11.2DS have more difficulties memorizing faces and visual-object characteristics of stimuli. In contrast, they have better performance in visuo-spatial memory tasks. The first focus of this study was to replicate these results in a larger sample of patients affected with 22q11.2DS and using a range of memory tasks. Moreover, we analyzed if the deficits were related to brain morphology in the structures typically underlying these abilities (ventral and dorsal visual streams). Finally, since the longitudinal development of visual memory is not clearly characterized in 22q11.2DS, we investigated its evolution from childhood to adolescence.

Methods

Seventy-one patients with 22q11.2DS and 49 control individuals aged between 9 and 16 years completed the Benton Visual Retention Test (BVRT) and specific subtests assessing visual memory from the Children’s Memory Scale (CMS). The BVRT was used to compute spatial and object memory errors. For the CMS, specific subtests were classified into ventral, dorsal, and mixed subtests. Longitudinal data were obtained from a subset of 26 patients and 22 control individuals.

Results

Cross-sectional results showed that patients with 22q11.2DS were impaired in all visual memory measures, with stronger deficits in visual-object memory and memory of faces, compared to visuo-spatial memory. No correlations between morphological brain impairments and visual memory were found in patients with 22q11.2DS. Longitudinal findings revealed that participants with 22q11.2DS made more object memory errors than spatial memory errors at baseline. This difference was no longer significant at follow-up.

Conclusions

Individuals with 22q11.2DS have impairments in visual memory abilities, with more pronounced difficulties in memorizing faces and visual-object characteristics. From childhood to adolescence, the visual cognitive profile of patients with 22q11.2DS seems globally stable even though some processes show an evolution with time. We hope that our results will help clinicians and caregivers to better understand the memory difficulties of young individuals with 22q11.2DS. This has a particular importance at school to facilitate recommendations concerning intervention strategies for these young patients.

     

Abnormal Auditory Processing and Underlying Structural Changes in 22q11.2 Deletion Syndrome

The 22q11.2 deletion syndrome (22q11.2 DS), one of the highest genetic risk for the development of schizophrenia, offers a unique opportunity to understand neurobiological and functional changes preceding the onset of the psychotic illness. Reduced auditory mismatch negativity response (MMN) has been proposed as a promising index of abnormal sensory processing and brain pathology in schizophrenia. However, the link between the MMN response and its underlying cerebral mechanisms in 22q11.2 DS remains unexamined. We measured auditory-evoked potentials to frequency deviant stimuli with high-density electroencephalogram and volumetric estimates of cortical and thalamic auditory areas with structural T1-weighted magnetic resonance imaging in a sample of 130 individuals, 70 with 22q11.2 DS and 60 age-matched typically developing (TD) individuals. Compared to TD group, the 22q11.2 deletion carriers reveal reduced MMN response and significant changes in topographical maps and decreased gray matter volumes of cortical and subcortical auditory areas, however, without any correlations between MMN alteration and structural changes. Furthermore, exploratory research on the presence of hallucinations (H⁺\H⁻) reveals no change in MMN response in 22q11.2DS (H⁺ and H⁻) as compared to TD individuals. Nonetheless, we observe bilateral volume reduction of the superior temporal gyrus and left medial geniculate in 22q11.2DSH⁺ as compared to 22q11.2DSH⁻ and TD participants. These results suggest that the mismatch response might be a promising neurophysiological marker of functional changes within the auditory pathways that might underlie elevated risk for the development of psychotic symptoms.     

Executive function in Williams and Down syndromes

Williams (WS) and Down (DS) syndromes are characterised by roughly opposing ability profiles. Relative verbal strengths and visuospatial difficulties have been reported in those with WS, while expressive language difficulties have been observed in individuals with DS. Few investigations into the executive function (EF) skills of these groups have examined the effect of verbal/visuospatial task type on performance. Analogous verbal and visuospatial measures were administered to these populations within four EF domains: executive-loaded working memory (ELWM), inhibition, fluency and set-shifting. Performance in both groups was compared to that of typically developing (TD) children using regression techniques controlling for potentially influential cognitive/developmental factors. Individuals with WS showed the expected relative visuospatial difficulties, as indicated by poorer performance than TD individuals, on tests of ELWM and fluency. Individuals with DS displayed the expected relative verbal difficulty in the domain of set-shifting. In addition, each population showed pervasive deficits across modality in one domain; ELWM for individuals with DS, and inhibition for individuals with WS. Individuals with WS and DS showed EF difficulties in comparison to a TD group, but, their executive performance was affected by EF task type (verbal/visuospatial) and EF domain in different ways. While the findings indicated that EF in these populations is characterised by a range of specific strengths and weaknesses, it was also suggested that the relative verbal/visuospatial strengths associated with each population do not consistently manifest across EF domains. Lastly, syndrome specificity was indicated by the differences in groups' performance patterns.     

Abnormal cortical activation during response inhibition in 22q11.2 deletion syndrome

22q11.2 deletion syndrome (22q11.2DS) is a well-known genetic risk factor for schizophrenia. The catechol-O-methyltransferase (COMT) gene falls within the 22q11.2 minimal critical region of the deletion. Brain activity, as measured by functional magnetic resonance imaging (fMRI) during a Go/NoGo, response inhibition task was assessed in adolescents with 22q11.2DS (n = 13), typically developing (TD) controls (n = 14), and controls with developmental disability (DD, n = 9). Subjects with 22q11.2DS were also genotyped for the COMT Met/Val polymorphism. Groups did not differ on task performance. However, compared to both control groups, the 22q11.2DS group showed greater brain activation within left parietal regions. Comparison of brain activation between 22q11.2DS Met and Val subgroups revealed significantly increased activation (Met>Val) in the cingulate but not the dorsolateral prefrontal cortex. These preliminary findings suggest that adolescents with 22q11.2DS compensate for executive dysfunction via recruitment of parietal regions. Further, the COMT Met subgroup of 22q11.2DS may recruit additional cingulate activation for tasks requiring attention and inhibition. 22q11.2DS is a unique model for learning about the deleterious effects of decreased dosage of the COMT gene on brain function.     

Executive function in Williams and Down syndromes

Williams (WS) and Down (DS) syndromes are characterised by roughly opposing ability profiles. Relative verbal strengths and visuospatial difficulties have been reported in those with WS, while expressive language difficulties have been observed in individuals with DS. Few investigations into the executive function (EF) skills of these groups have examined the effect of verbal/visuospatial task type on performance. Analogous verbal and visuospatial measures were administered to these populations within four EF domains: executive-loaded working memory (ELWM), inhibition, fluency and set-shifting. Performance in both groups was compared to that of typically developing (TD) children using regression techniques controlling for potentially influential cognitive/developmental factors. Individuals with WS showed the expected relative visuospatial difficulties, as indicated by poorer performance than TD individuals, on tests of ELWM and fluency. Individuals with DS displayed the expected relative verbal difficulty in the domain of set-shifting. In addition, each population showed pervasive deficits across modality in one domain; ELWM for individuals with DS, and inhibition for individuals with WS. Individuals with WS and DS showed EF difficulties in comparison to a TD group, but, their executive performance was affected by EF task type (verbal/visuospatial) and EF domain in different ways. While the findings indicated that EF in these populations is characterised by a range of specific strengths and weaknesses, it was also suggested that the relative verbal/visuospatial strengths associated with each population do not consistently manifest across EF domains. Lastly, syndrome specificity was indicated by the differences in groups’ performance patterns.     

Baseline connectome modular abnormalities in the childhood phase of a longitudinal study on individuals with chromosome 22q11.2 deletion syndrome

Occurring in at least 1 in 3,000 live births, chromosome 22q11.2 deletion syndrome (22q11DS) produces a complex phenotype that includes a constellation of medical complications such as congenital cardiac defects, immune deficiency, velopharyngeal dysfunction, and characteristic facial dysmorphic features. There is also an increased incidence of psychiatric diagnosis, especially intellectual disability and ADHD in childhood, lifelong anxiety, and a strikingly high rate of schizophrenia spectrum disorders, which occur in around 30% of adults with 22q11DS. Using innovative computational connectomics, we studied how 22q11DS affects high‐level network signatures of hierarchical modularity and its intrinsic geometry in 55 children with confirmed 22q11DS and 27 Typically Developing (TD) children. Results identified 3 subgroups within our 22q11DS sample using a K‐means clustering approach based on several midline structural measures‐of‐interests. Each subgroup exhibited distinct patterns of connectome abnormalities. Subtype 1, containing individuals with generally healthy‐looking brains, exhibited no significant differences in either modularity or intrinsic geometry when compared with TD. By contrast, the more anomalous 22q11DS Subtypes 2 and 3 brains revealed significant modular differences in the right hemisphere, while Subtype 3 (the most anomalous anatomy) further exhibited significantly abnormal connectome intrinsic geometry in the form of left–right temporal disintegration. Taken together, our findings supported an overall picture of (a) anterior‐posteriorly differential interlobar frontotemporal/frontoparietal dysconnectivity in Subtypes 2 and 3 and (b) differential intralobar dysconnectivity in Subtype 3. Our ongoing studies are focusing on whether these subtypes and their connnectome signatures might be valid biomarkers for predicting the degree of psychosis‐proneness risk found in 22q11DS. Hum Brain Mapp 39:232–248, 2018. © 2017 Wiley Periodicals, Inc.     

Developmental trajectories of brain structure in adolescents with 22q11.2 deletion syndrome: a longitudinal study

The 22q11.2 deletion syndrome (22q11.2DS) is associated with very high rates of schizophrenia-like psychosis and cognitive deficits. Here we report the results of the first longitudinal study assessing brain development in individuals with 22q11.2DS. Twenty-nine children with 22q11.2DS and 29 age and gender matched controls were first assessed during childhood or early adolescence; Nineteen subjects with 22q11.2DS and 18 controls underwent follow-up during late adolescence-early adulthood. The 22q11.2DS subjects showed greater longitudinal increase in cranial and cerebellar white matter, superior temporal gyrus, and caudate nucleus volumes. They also had a more robust decrease in amygdala volume. Verbal IQ (VIQ) scores of the 22q11.2DS group that developed psychotic disorders declined significantly between assessments. Decline in VIQ in 22q11.2DS was associated with more robust reduction of left cortical grey matter volume. No volumetric differences were detected between psychotic and nonpsychotic subjects with 22q11.2DS. Brain maturation associated with verbal cognitive development in 22q11.2DS varies from that observed in healthy controls. Further longitudinal studies are likely to elucidate brain developmental trajectories in 22q11.2DS and their association to psychotic disorders and cognitive deficits in this population.     

The Neurocognitive Phenotype of the 22Q11.2 Deletion Syndrome: Selective Deficit in Visual-Spatial Memory

The 22q11.2 deletion syndrome (velocardiofacial/DiGeorge syndrome) is associated with a high frequency of learning disabilities. Although previous work has demonstrated that verbal skills are typically better preserved than non-verbal skills on both IQ and academic achievement testing in children with this syndrome, such measures are not sufficiently specific to determine a selective cognitive deficit. As part of an ongoing prospective study of patients with this syndrome, 29 children aged 517 with confirmed 22q11.2 deletions were assessed with a comprehensive neuropsychological test battery, including matched tasks of verbal and visuospatial memory. Results indicate that 22q patients displayed a selective deficit in visual-spatial memory, which was mirrored by deficits in arithmetic and general visual-spatial cognition. Further, a dissociation between visual-spatial and object memory was observed, indicating further selectivity of this pattern of deficit, and providing evidence for the dissociability of these components of visual cognition. These results indicate that children with 22q11.2 deletions display a specific neurocognitive phenotype, and suggest that this region of Chromosome 22q11 may harbor a gene or genes relevant to the etiology of nonverbal learning deficits.     

The neurocognitive phenotype of the 22q11.2 deletion syndrome: selective deficit in visual-spatial memory.

The 22q11.2 deletion syndrome (velocardiofacial/DiGeorge syndrome) is associated with a high frequency of learning disabilities. Although previous work has demonstrated that verbal skills are typically better preserved than non-verbal skills on both IQ and academic achievement testing in children with this syndrome, such measures are not sufficiently specific to determine a selective cognitive deficit. As part of an ongoing prospective study of patients with this syndrome, 29 children aged 5-17 with confirmed 22q11.2 deletions were assessed with a comprehensive neuropsychological test battery, including matched tasks of verbal and visuospatial memory. Results indicate that 22q patients displayed a selective deficit in visual-spatial memory, which was mirrored by deficits in arithmetic and general visual-spatial cognition. Further, a dissociation between visual-spatial and object memory was observed, indicating further selectivity of this pattern of deficit, and providing evidence for the dissociability of these components of visual cognition. These results indicate that children with 22q11.2 deletions display a specific neurocognitive phenotype, and suggest that this region of Chromosome 22q11 may harbor a gene or genes relevant to the etiology of nonverbal learning deficits.