Aim In this study, we explored the integrity of the inferior longitudinal fasciculus (ILF) by means of diffusion tensor imaging tractography in children with visual perceptual impairment, and more specifically, object recognition deficits, compared with typically developing children.Methods Eleven individuals (nine males, two females; mean age 7y 8mo; range 3y 5mo–13y) were assessed with the L94 visual perceptual battery after assessment of performance age. In all participants, an ophthalmological evaluation was carried out. Diffusion tensor imaging tractography of the ILF was performed. The mean fractional anisotropy was determined for every child and compared with data for 11 age‐ and sex‐matched typically developing children.Results The mean fractional anisotropy value in the left ILF was consistently lower in the study participants than in the comparison group. The five children with L94 impairment showed a significantly lower ILF fractional anisotropy on the left as well as on the right side. Furthermore, the decrease in ILF fractional anisotropy was correlated with the number of impaired subtests.Interpretation The results suggest an association between ILF integrity loss and object recognition deficits. Moreover, the severity of clinical impairment is reflected in the degree of ILF integrity loss. Therefore, the ILF plays a potential role in object recognition.
The objective of the study was to investigate the screening utility of a questionnaire for cerebral visual impairment (CVI) by correlating the questionnaire with diagnostic tools such as the L94, the Test of Visual Perceptual Skills - Revised and the Visual Perception subtask of the Beery test of VisuoMotor Integration. The questionnaire consisted of 46 items, exploring different characteristics of CVI. We consecutively recruited 91 children. Parents filled out the questionnaire after which all children were seen for a diagnostic evaluation of CVI. There were 58 boys. Subjects’ mean age was 6.10 years. A median of 12 items was ticked in the 45 children with CVI and 7 in the children without impairment. The domain ‘visual attitude’ scored positive most frequently. A logistic regression model using individual items, yielded Receiver Operating Curves for the questionnaire with good areas under the curve of 0.81 against the L94, 0.78 against the TVPS-R and 0.84 against the VP subtask. The sum score of the 6 domains was found to be an easy-obtainable score with a good sensitivity and specificity profile. This CVI questionnaire is a viable tool that has the potential of being implemented as part of a routine screening procedure for CVI.
Most people with intellectual disability (ID) do not receive a molecular diagnosis following genetic testing. To identify new etiologies of ID, we performed a genetic association analysis comparing the burden of rare variants in 41,132 noncoding genes between 5,529 unrelated cases and 46,401 unrelated controls. RNU4-2, which encodes U4 small nuclear RNA, a critical component of the spliceosome, was the most strongly associated gene. We implicated de novo variants among 47 cases in two regions of RNU4-2 in the etiology of a syndrome characterized by ID, microcephaly, short stature, hypotonia, seizures and motor delay. We replicated this finding in three collections, bringing the number of unrelated cases to 73. Analysis of national genomic diagnostic data showed RNU4-2 to be a more common etiological gene for neurodevelopmental abnormality than any previously reported autosomal gene. Our findings add to the growing evidence of spliceosome dysfunction in the etiologies of neurological disorders.
Preterm infants show a higher incidence of cognitive, social, and behavioral problems, even in the absence of major medical complications during their stay in the neonatal intensive care unit (NICU). Several authors suggest that early-life experience of stress and procedural pain could impact cerebral development and maturation resulting in an altered development of cognition, behavior, or motor patterns in later life. However, it remains very difficult to assess this impact of procedural pain on physiological development. This study describes the maturation of electroencephalogram (EEG) signals and heart rate variability in a prospective cohort of 92 preterm infants (<34 weeks gestational age) during their NICU stay. We took into account the number of noxious, ie, skin-breaking, procedures they were subjected in the first 5 days of life, which corresponded to a median age of 31 weeks and 4 days. Using physiological signal modelling, this study shows that a high exposure to early procedural pain, measured as skin-breaking procedures, increased the level of discontinuity in both EEG and heart rate variability in preterm infants. These findings have also been confirmed in a subset of the most vulnerable preterm infants with a gestational age lower than 29 weeks. We conclude that a high level of early pain exposure in the NICU increases the level of functional dysmaturity, which can ultimately impact preterm infants' future developmental outcome.