Karen Lidzba

Aims: In the recent years, the preoperative assessment of language functions using functional MRI (fMRI) has become increasingly important in clinical practice, also for pediatric patients. Here, interpretation of results usually relies on scanner-generated statistical parameter maps. However, much more extensive processing approaches are used in the research arena. This study was aimed to directly compare these different approaches. Methods: For this project, we used fMRI data sets collected in a pediatric epilepsy center from January 2010 to September 2014. Demographic information of the patients was collected, and data sets from the vowel identification task were processed using SPM12 software (FIL, University College, London) running in MATLAB. After an extensive preprocessing and final spatial smoothing (FWHM = 4 mm), statistical parameter maps were generated using the general linear model. These, as well as the automatically generated statistical maps from the MRI scanner, were then assessed regarding their lateralization in the frontal lobe using a robust, threshold-free lateralization index (LI). Results: There were 173 series of 84 patients (median age, 13.49 [MAD, 2.81] years; sex, M 45 and W 39; handedness, L 22 and R 56, ambidextrous 4, and unknown 2). The results of both approaches were very similar, with LI = 0.35 (0.35) versus LI = 0.30 (0.35). The difference was not significant (p = 0.3; Mann–Whitney U test). However, several individual data sets showed substantial differences when comparing the two approaches, which would also lead to a change in the interpretation of their hemispheric dominance. Conclusion: The comparison of scanner-generated versus externally calculated statistical maps yields only minor differences on the group level. However, there are several individual cases with substantial discrepancies. The analysis of the underlying factors (data quality, subject movement, etc.) is currently ongoing. Keywords: functional MRI, language lateralization, hemispheric dominance.

Background: A perinatal left hemispheric infarct can, in most cases, be well compensated with respect to language. At this early developmental stage, not only perilesional, but also contralesional reorganization of language can support functionally successful compensation. Data on infarcts acquired in childhood and adolescence is, however, less clear. After language acquisition, left-hemispheric infarcts often cause aphasia, with variable recovery. Patients with persistent aphasic symptoms document an obvious lack of a successful reorganization. The age at infarct probably significantly influences the compensatory potential, but literature on this matter is scarce. Method: In a cooperative project of Schön Klinik Vogtareuth (Clinic for Pediatric Neurology and Neurological Rehabilitation) and the University Children’s Hospital Tübingen (Pediatric neurology), we first identified all patients treated for a left-hemispheric infarct between the age of 2 months and 17 years. All patients with documented aphasia in the acute phase were asked to complete a short questionnaire regarding language functions (production, comprehension, reading, and writing). Results: Of the 35 patients addressed, 24 patients (69%) returned the questionnaire. One patient was deceased, for another patient no current address could be obtained. For the whole group, the majority of patients reported “no” (13/24) or “some” (7/24) language problems, only 3 of 24 reported considerable problems (in more than one area). All six patients who had suffered the infarct before the age of 5 years reported no language problems, two patients who were 5 years old at the time of the infarction reported “some” problems. Considerable problems were reported only by patients aged 7 years and older. Discussion: Up to the age of 4 years, good recovery of language function seems to be the rule, even after extensive left-hemispheric infarcts. After that age, residual aphasic symptoms may persist. Obviously, the time frame in which an effective right-hemispheric language reorganization is possible seems to close around the age of 5 years. Additional factors, such as epilepsy and intellectual abilities, must be considered in future studies.

Aim Attention deficit with or without hyperactivity (AD[H]D) is a common comorbidity of neurofibromatosis type 1 (NF 1). We tested the hypothesis that permanent medication with methylphenidate can improve cognitive functioning in children with NF 1 and comorbid AD(H)D. Patients and Method We retrospectively analyzed data of a clinical sample of patients with NF 1 with or without AD(H)D, who underwent standardized neuropsychological diagnostics twice (age range: T1, 6–14 years; T2, 7–16 years; mean interval, 49.09 months). A total of 16 children without AD(H)D (nine females) were compared with 14 unmedicated children with AD(H)D (eight females) and to 13 medicated children with AD(H)D (two females). Effects of medication and attention on cognitive outcome (IQ) were tested by repeated measures analysis of covariance (rmANCOVA). Results Medicated children with NF 1 improved significantly in full-scale IQ from T1 to T2 (IQ[T1] = 80.38, IQ[T2] = 98.38, confidence interval [diff]: –25.59 to –10.40, p < 0.0001), this effect was not evident for the other groups. With attention measures as covariates, the effect remained marginally significant. Conclusion Children and adolescents with NF 1 and comorbid AD(H)D may profit from MPH medication regarding general cognition. This effect could be specific for the group of patients with NF 1, and cannot be explained solely by improvements in attention. Controlled, prospective studies are warranted to corroborate our findings.

Complex visuospatial processing relies on distributed neural networks involving occipital, parietal and frontal brain regions. Effects of physiological maturation (during normal brain development) and proficiency on tasks requiring complex visuospatial processing have not yet been studied extensively, as they are almost invariably interrelated. We therefore aimed at dissociating the effects of age and performance on functional MRI (fMRI) activation in a complex visual search task. In our cross-sectional study, healthy children and adolescents (n = 43, 19 females, 7-17 years) performed a complex visual search task during fMRI. Resulting activation was analysed with regard to the differential effects of age and performance. Our results are compatible with an increase in the neural network's efficacy with age: within occipital and parietal cortex, the core regions of the visual exploration network, activation increased with age, and more so in the right than in the left hemisphere. Further, activation outside the visual search network decreased with age, mainly in left inferior frontal, middle temporal, and inferior parietal cortex. High-performers had stronger activation in right superior parietal cortex, suggesting a more mature visual search network. We could not see effects of age or performance in frontal cortex. Our results show that effects of physiological maturation and effects of performance, while usually intertwined, can be successfully disentangled and investigated using fMRI in children and adolescents.