The Impact of Axial Eye Growth on Foveal Avascular Zone Measurements in Children.

SIGNIFICANCE: Foveal avascular zone (FAZ) area is a frequently used biomarker in diseases impacting the retinal vasculature in pediatric populations. Variation in axial length between individuals results in differences in lateral image scale, which affect the accuracy of FAZ area measurements. Accordingly, changes in axial length over time within individual children would affect estimates of FAZ area change. PURPOSE: This study aimed to quantify how changes in axial length over time affect estimates of FAZ area change using optical coherence tomography angiography (OCT-A) images. METHODS: Twenty pediatric participants (<18 years old) and 40 adult participants were imaged on Optovue's Avanti system (Fremont, CA) and had axial length measurements acquired at two time points. The FAZ was segmented twice using the OCT-A image at each time point. Foveal avascular zone area was estimated at both time points using the assumed/fixed axial length of the OCT-A device (unscaled) and using the participant's axial length (scaled). Changes in FAZ area over time were compared between the pediatric and adult groups using both unscaled and scaled data. RESULTS: The average ± standard deviation follow-up time was 3.35 ± 1.66 years for the pediatric group and 2.90 ± 1.65 years for the adult group. Using unscaled data, FAZ area seemed to decrease between visits in the pediatric group (P = .004), whereas the FAZ area increased between visits in the adult group (P = .003). When correctly scaled data were used, the FAZ area still increased between visits for the adult group (P < .001), although the FAZ area no longer showed a significant change between visits for the pediatric group (P = .37). When comparing the normalized FAZ area change across visits between unscaled and scaled data, a significant difference was found between the adult and pediatric groups (P < .001). CONCLUSIONS: Scaled data should be used when measuring FAZ area in pediatric populations, especially in longitudinal studies.

Attitudes, perceptions, and use of marijuana in youth with multiple sclerosis.

BACKGROUND: Studies have shown a negative impact on cognition and brain volume in marijuana-using adult multiple sclerosis (MS) patients and healthy adolescents. Given that onset of MS during childhood and adolescence negatively impacts brain growth and the normal maturation of neuronal networks, the addition of marijuana exposure in these youth may be even more harmful. OBJECTIVE: Determine attitudes toward and prevalence of recreational marijuana use in MS youth. METHODS: We surveyed 52 consecutive pediatric-onset MS patients from three pediatric MS centers in the United States. Participants answered a structured questionnaire to capture attitudes toward marijuana and personal use habits, if present. RESULTS: Nearly half reported use of marijuana, with the majority beginning to use in mid-to-late adolescence. The most popular reasons for using marijuana were relaxation (72%), improvement of medical problems (64%), and stress reduction (52%). Over half (64%) of marijuana users perceived it to have negative effects on memory and focus. Cost and access were not barriers to use, despite all respondents being less than age 21. CONCLUSION: Youth with MS endorse recreational marijuana as safe, and many use marijuana frequently despite appreciating a negative impact on memory. More detailed understanding of the long-term impact of marijuana use in youth with MS is needed.

Thalamic reductions in children with chromosome 22q11.2 deletion syndrome.

Children with chromosome 22q11.2 deletion syndrome (22q) suffer from physical and behavioral dysfunctions, including neuroanatomical anomalies, visuo-spatial processing deficits, and increased risk for psychopathology. Reduced total brain volume, parietal lobe volume, and cerebellar volumes, enlarged ventricles, and increased basal ganglia volumes have been reported. Since previous literature has related the pulvinar nucleus of the thalamus to visuo-spatial processing, we compared the thalamic volume in children with 22q to typically developing controls. Children with 22q showed a significant reduction of the thalamus compared with normally developing children, specifically in the posterior portion of the thalamus, including the pulvinar nucleus. These results provide the first evidence for a potential relationship between posterior thalamic reductions and the characteristic visuo-spatial deficits demonstrated in this group.

Maladaptive conflict monitoring as evidence for executive dysfunction in children with chromosome 22q11.2 deletion syndrome.

Using an adaptation of the Attentional Networks Test, we investigated aspects of executive control in children with chromosome 22q11.2 deletion syndrome (DS22q11.2), a common but not well understood disorder that produces non-verbal cognitive deficits and a marked incidence of psychopathology. The data revealed that children with DS22q11.2 demonstrated greater difficulty than controls in locating and processing target items in the presence of distracters. Importantly, children with DS22q11.2 showed a deficit in the ability to monitor and adapt to stimulus conflict. These data provide evidence of inadequate conflict adaptation in children with DS22q11.2, a problem that is also present in schizophrenia. The findings of specific executive dysfunction in this group may provide a linkage between particular genetic abnormalities and the development of psychopathology.

A multilevel analysis of cognitive dysfunction and psychopathology associated with chromosome 22q11.2 deletion syndrome in children.

We present a multilevel approach to developing potential explanations of cognitive impairments and psychopathologies common to individuals with chromosome 22q11.2 deletion syndrome. Results presented support our hypothesis of posterior parietal dysfunction as a central determinant of characteristic visuospatial and numerical cognitive impairments. Converging data suggest that brain development anomalies, primarily tissue reductions in the posterior brain and changes to the corpus callosum, may affect parietal connectivity. Further findings indicate that dysfunction in "frontal" attention systems may explain some executive cognition impairments observed in affected children, and that there may be links between these domains of cognitive function and some of the serious psychiatric conditions, such as attention-deficit/hyperactivity disorder, autism, and schizophrenia, that have elevated incidence rates in the syndrome. Linking the neural structure and the cognitive processing levels in this way enabled us to develop an elaborate structure/function mapping hypothesis for the impairments that are observed. We show also, that in the case of the catechol-O-methyltransferase gene, a fairly direct relationship between gene expression, cognitive function, and psychopathology exists in the affected population. Beyond that, we introduce the idea that variation in other genes may further explain the phenotypic variation in cognitive function and possibly the anomalies in brain development.