Mirrored brain organization: Statistical anomaly or reversal of hemispheric functional segregation bias?

Humans demonstrate a prototypical hemispheric functional segregation pattern, with language and praxis lateralizing to the left hemisphere and spatial attention, face recognition, and emotional prosody to the right hemisphere. In this study, we used fMRI to determine laterality for all five functions in each participant. Crucially, we recruited a sample of left-handers preselected for atypical (right) language dominance (n = 24), which allowed us to characterize hemispheric asymmetry of the other functions and compare their functional segregation pattern with that of left-handers showing typical language dominance (n = 39). Our results revealed that most participants with left language dominance display the prototypical pattern of functional hemispheric segregation (44%) or deviate from this pattern in only one function (35%). Similarly, the vast majority of right language dominant participants demonstrated a completely mirrored brain organization (50%) or a reversal for all but one cognitive function (32%). Participants deviating by more than one function from the standard segregation pattern showed poorer cognitive performance, in line with an oft-presumed biological advantage of hemispheric functional segregation.

Laterality indices consensus initiative (LICI): A Delphi expert survey report on recommendations to record, assess, and report asymmetry in human behavioural and brain research.

Laterality indices (LIs) quantify the left-right asymmetry of brain and behavioural variables and provide a measure that is statistically convenient and seemingly easy to interpret. Substantial variability in how structural and functional asymmetries are recorded, calculated, and reported, however, suggest little agreement on the conditions required for its valid assessment. The present study aimed for consensus on general aspects in this context of laterality research, and more specifically within a particular method or technique (i.e., dichotic listening, visual half-field technique, performance asymmetries, preference bias reports, electrophysiological recording, functional MRI, structural MRI, and functional transcranial Doppler sonography). Experts in laterality research were invited to participate in an online Delphi survey to evaluate consensus and stimulate discussion. In Round 0, 106 experts generated 453 statements on what they considered good practice in their field of expertise. Statements were organised into a 295-statement survey that the experts then were asked, in Round 1, to independently assess for importance and support, which further reduced the survey to 241 statements that were presented again to the experts in Round 2. Based on the Round 2 input, we present a set of critically reviewed key recommendations to record, assess, and report laterality research for various methods.

Neonatal brachial plexus palsy and hand representation in children and young adults.

AIM: To assess the impact of neonatal brachial plexus palsy (NBPP) on higher-order hand representation. METHOD: Eighty-two left-handed children and adolescents with and without right-sided NBPP were recruited. Thirty-one participants with NBPP (mean age [SD] 11y 4mo [4y 4mo]; age range 6y 2mo-21y 0mo; 15 females; C5-6, n=4, C5-7, n=12, C5-T1, n=11, C5-T1 with Horner sign, n=4) were assessed along with 30 controls (mean age 11y 5mo [4y 4mo]; age range 6y 7mo-21y 7mo; 14 females). Participants' estimated hand size and shape on measure of implicit and explicit hand representation was assessed. A linear mixed model (LMM) was used to investigate the effect of condition, sensorimotor impairment, and age. RESULTS: Individuals with NBPP showed a significant difference in implicit hand representation between affected and non-affected hands. LMM confirmed a significant influence of the severity of sensorimotor injury. Only the estimated implicit hand representation was associated with age, with a significant difference between 6- to 8-year-olds and 9- to 10-year-olds. INTERPRETATION: The effect of sensorimotor impairment on central hand representation in individuals with NBPP is specific due to its implicit component and is characterized by finger length underestimation in the affected hand compared to the characteristic underestimation in the unaffected hand. Neither NBPP nor age impacted the explicit hand estimate. This study confirms the importance of sensorimotor contribution to the development of implicit hand representation.

Fibre-specific laterality of white matter in left and right language dominant people.

Language is the most commonly described lateralised cognitive function, relying more on the left hemisphere compared to the right hemisphere in over 90% of the population. Most research examining the structure-function relationship of language lateralisation only included people showing a left language hemisphere dominance. In this work, we applied a state-of-the-art "fixel-based" analysis approach, allowing statistical analysis of white matter micro- and macrostructure on a fibre-specific level in a sample of participants with left and right language dominance (LLD and RLD). Both groups showed a similar extensive pattern of white matter lateralisation including a comparable leftwards lateralisation of the arcuate fasciculus, regardless of their functional language lateralisation. These results suggest that lateralisation of language functioning and the arcuate fasciculus are driven by independent biases. Finally, a significant group difference of lateralisation was detected in the forceps minor, with a leftwards lateralisation in LLD and rightwards lateralisation for the RLD group.

Hand size representation in healthy children and young adults.

Whereas we experience our body as a coherent volumetric object, the brain appears to maintain highly fragmented representations of individual body parts. Little is known about how body representations of hand size and shape are built and evolve during infancy and young adulthood. This study aimed to investigate the effect of hand side, handedness, and age on the development of central hand size representation. The observational study with comparison groups was conducted with 90 typically developing Belgian school children and young adults (48 male and 42 female; age range = 5.0-23.0 years; 49 left-handed and 41 right-handed). Participants estimated their hand size and shape using two different tasks. In the localization task, participants were verbally cued to judge the locations of 10 anatomical landmarks of an occluded hand. An implicit hand size map was constructed and compared with actual hand dimensions. In the template selection task, the explicit hand shape was measured with a depictive method. Hand shape indexes were calculated and compared for the actual, implicit, and explicit conditions. Participants were divided into four age groups (5-8 years, 9-10 years, 11-16 years, and 17-23 years). Implicit hand maps featured underestimation of finger length and overestimation of hand width, which is already present in the youngest children. Linear mixed modeling revealed no influence of hand side on finger length underestimation; nonetheless, a significant main effect of age (p = .001) was exposed. Sinistrals aged 11 to 16 years showed significantly less underestimation (p = .03) than dextrals of the same age. As for the hand shape, the implicit condition differed significantly with the actual and explicit conditions (p < .001). Again, the implicit shape index was subjected to handedness and age effects, with significant differences being found between sinistrals and dextrals in the age groups of 9 and 10 years (p = .029) and 11 to 16 years (p < .001). In conclusion, the implicit metric component of the hand representation in children and young adults is misperceived, featuring shortened fingers and broadened hands since a very young age. Crucially, the finger length underestimation increases with age and shows a different developmental trajectory for sinistrals and dextrals. In contrast, the explicit hand shape is approximately veridical and seems immune from age and handedness effects. This study confirms the dual character of somatoperception and establishes a point of reference for children and young adults.

Early electrodiagnosis in the management of neonatal brachial plexus palsy: A systematic review.

Neonatal brachial plexus palsy (NBPP) is a prominent form of newborn morbidity with a potentially disabling persistence. Neurosurgical intervention is indicated in select NBPP patients. Early prognostic assessment would facilitate rational selection of those infants for surgery. We conducted a systematic literature review to determine the prognostic value of early electrodiagnosis (EDx) in NBPP. We included 16 observational studies with a total sample size of 747 children. Risk of bias and quality of evidence were rated. Wide variation was found in EDx techniques, outcome algorithms, and decisionmaking. Nevertheless, the most methodologically sound studies support the use of EDx, at standardized time-frames, as a key prognostic modality for complementing clinical judgment and neuroimaging. An accurate knowledge of the underlying anatomy of the nerve injury helps to counsel families and to guide reconstructive strategy.

Heterogeneous Response of Chemotherapy-Related Cognitive Decline in Patients with Breast Cancer: A Prospective Study.

OBJECTIVE: A significant proportion of adjuvant-treated breast cancer patients experience cognitive decline, challenging the person's ability to return to normal activities after treatment. However, not every patient experiences cognitive problems, and even in patients with impairments, determining clinically important cognitive decline remains challenging. Our objective was to explore differences in neuropsychological performance following adjuvant chemotherapy (CT) in patients with breast cancer. METHOD: We conducted a prospective observational study in an Oncology Breast Clinic and assessed neuropsychological performance before and after adjuvant CT and in non-CT-treated women with breast cancer and healthy controls (HCs). Standardised between-group differences and regression-based change scores were calculated. RESULTS: CT-treated patients (n = 66) performed significantly different from non-CT-treated patients (n = 39) and HCs (n = 56). There was a significant effect on verbal fluency (p = .0013). CT performed significantly worse than non-CT and HC [effect size (ES) = .89, p < .001 and ES = .61, p ≤ .001, respectively] and from HCs with regard to proactive interference (ES = .62, p ≤ .001). Regression-based scores revealed more severe cognitive decline in the CT-treated group [24.24% (16/66)] than in the non-CT-treated group [15.20% (6/39)] and HC group [7.14% (4/56)]. Patients who underwent CT and showed cognitive decline were less educated and older, with significantly lower baseline scores. CONCLUSIONS: CT-treated patients showed more vulnerability on cognitive control and monitoring than non-CT-treated breast cancer patients and HCs. Older patients with less education and lower baseline cognitive performance represent a group at risk for cognitive decline following CT. Identification of patients at risk for decline could improve targeted support and rehabilitation.

Risk factors for neonatal brachial plexus palsy: a systematic review and meta-analysis.

AIM: To provide a comprehensive update on the most prevalent, significant risk factors for neonatal brachial plexus palsy (NBPP). METHOD: Cochrane CENTRAL, MEDLINE, Web of Science, Embase, and ClinicalTrials.gov were searched for relevant publications up to March 2019. Studies assessing risk factors of NBPP in relation to typically developing comparison individuals were included. Meta-analysis was performed for the five most significant risk factors, on the basis of the PRISMA statement and MOOSE guidelines. Pooled odds ratios (ORs), 95% confidence intervals (CIs), and across-study heterogeneity (I2 ) were reported. Reporting bias and quality of evidence was rated. In addition, we assessed the incidence of NBPP. RESULTS: Twenty-two observational studies with a total sample size of 29 419 037 live births were selected. Significant risk factors included shoulder dystocia (OR 115.27; 95% CI 81.35-163.35; I2 =92%), macrosomia (OR 9.75; 95% CI 8.29-11.46; I2 =70%), (gestational) diabetes (OR 5.33; 95% CI 3.77-7.55; I2 =59%), instrumental delivery (OR 3.8; 95% CI 2.77-5.23; I2 =77%), and breech delivery (OR 2.49; 95% CI 1.67-3.7; I2 =70%). Caesarean section appeared as a protective factor (OR 0.13; 95% CI 0.11-0.16; I2 =41%). The pooled overall incidence of NBPP was 1.74 per 1000 live births. It has decreased in recent years. INTERPRETATION: The incidence of NBPP is decreasing. Shoulder dystocia, macrosomia, maternal diabetes, instrumental delivery, and breech delivery are risk factors for NBPP. Caesarean section appears as a protective factor. WHAT THIS PAPER ADDS: The overall incidence of neonatal brachial plexus palsy is 1.74 per 1000 live births. The incidence has declined significantly. Shoulder dystocia, macrosomia, maternal diabetes, instrumental delivery, and breech delivery are the main risk factors. Prevention is difficult owing to unpredictability and often labour-related risk.

Evaluating the performance of the visual half field paradigm as a screening tool to detect right hemispheric language dominance.

Language is among the most studied functional asymmetries, yet little is known about right hemispheric language dominance. Because of its low prevalence, including a big sample of individuals with this variant of brain organization implies testing large groups, which may not be feasible when using expensive techniques. One solution involves screening a large sample using a cost-efficient method and next inviting only those participants flagged as potentially right dominant for follow-up investigation. The behavioural visual half field paradigm has previously been validated and successfully applied in this manner. We report a large-scale visual half field screening performed in 315 left-handers to detect such individuals for subsequent MRI scanning. Of 38 cases selected as probably right language dominant based on a left visual half field advantage (>20 ms), 22 (58%) were confirmed by language fMRI to be rightward lateralized. This study also explored means to improve the predictive performance of the visual half field task. While we found its performance depended strongly on the chosen cut-off, overall, reaction time criteria resulted in higher true positive rates, while those based on accuracy led to superior positive predictive values. The most optimal strategy, however, may involve combining criteria considering both accuracy and reaction time.

Prefrontal and temporal cortical thickness in adolescents with traumatic brain injury.

AIM: To investigate the impact of traumatic injury on the developing prefrontal-temporal adolescent cortex, and correlated brain structural measures with neurocognitive functioning. METHOD: Nineteen adolescents (12 males, 7 females, age range: 11-17y, mean 15y 8mo, standard deviation 1y 7mo, median 15y 11mo) with traumatic brain injury (TBI) were included. Cortical thickness of frontal and temporal lobes was assessed using magnetic resonance imaging. We correlated cortical thickness of prefrontal-temporal regions with age, time since injury, and neurocognitive functioning, and compared these results with a matched control cohort without TBI. RESULTS: We found thinner prefrontal (p=0.039) and temporal cortices (p=0.002) in adolescents with TBI compared to typically developing children. Furthermore, significant age effect was observed on the prefrontal (r=-0.75, p=0.003) and temporal (r=-0.66, p=0.013) cortical thickness in typically developing adolescents, but not in adolescents with TBI. Executive function (measured using the Behaviour Rating Inventory of Executive Function questionnaire, with lower scores meaning higher functioning) was correlated with prefrontal cortical thickness in typically developing adolescents (r=0.72, p=0.009). Opposite trends were found for correlations between cortical thickness and executive function in the TBI and control cohort. INTERPRETATION: Structural maturation in typically developing adolescents correlates with functional development: the older the adolescent, the thinner the prefrontal cortex, the better executive function. In adolescents with TBI we observed an opposite trend, that appeared significantly different from the control group: the thinner the prefrontal and temporal cortex, the worse executive functioning. WHAT THIS PAPER ADDS: Cortical thickness is negatively correlated with age in typically developing adolescents. Prefrontal cortex thickness correlates negatively with executive function in typically developing adolescents. Correlations between cortical thickness and executive functioning rise for adolescents without traumatic brain injury (TBI). Correlations between cortical thickness and executive functioning fall for adolescents with TBI. Adolescents with TBI have a long-term impairment of adaptive functioning in daily living.

ESPESOR CORTICAL PREFRONTAL Y TEMPORAL EN ADOLESCENTES CON LESIÓN CEREBRAL TRAUMÁTICA: OBJETIVO: Investigar el impacto de la lesión traumática en el desarrollo de la corteza prefrontal-temporal en adolescentes y las medidas estructurales cerebrales correlacionadas con el funcionamiento neurocognitivo. MÉTODO: Diecinueve adolescentes (12 varones, siete mujeres, rango de edad: 11-17 años, media: 15 años 8 meses, desviación estándar: 1 años 7 meses, mediana: 15 años 11 meses) con lesión cerebral traumática (LCT). El grosor cortical de los lóbulos frontal y temporal se evaluó mediante imágenes de resonancia magnética. Se correlacionó el grosor cortical de las regiones prefrontal-temporales con la edad, el tiempo transcurrido desde la lesión y el funcionamiento neurocognitivo, y se compararon estos resultados con una cohorte de control emparejada sin TCE. RESULTADOS: Encontramos cortezas prefrontales (p = 0.039) y corticales temporales delgadas (p = 0.002) en adolescentes con LCT en comparación con niños con desarrollo típico. Además, se observó un efecto significativo de la edad en el grosor cortical prefrontal (r = -0.75, p = 0.003) y temporal (r = -0.66, p = 0.013) en adolescentes de desarrollo típico, pero no en adolescentes con LCT. La función ejecutiva (medida con el cuestionario Inventario de clasificación de la conducta de la función ejecutiva, con puntuaciones más bajas que significan un funcionamiento más alto) se correlacionó con el grosor cortical prefrontal en adolescentes con desarrollo típico (r = 0.72, p = 0.009). Se encontraron tendencias opuestas para las correlaciones entre el grosor cortical y la función ejecutiva en el LCT y la cohorte de control. INTERPRETACIÓN: La maduración estructural en adolescentes con desarrollo típico se correlaciona con el desarrollo funcional: cuanto mayor es el adolescente, más delgada es la corteza prefrontal, y mejor la función ejecutiva. En adolescentes con LCT observamos una tendencia opuesta, que parecía significativamente diferente del grupo de control: cuanto más delgada era la corteza prefrontal y temporal, peor el funcionamiento ejecutivo.

ESPESSURA PRÉ-FRONTAL E TEMPORAL EM ADOLESCENTES COM LESÃO CEREBRAL TRAUMÁTICA: OBJETIVO: Investigar o impacto da lesão cerebral traumática no córtex pré-frontal -temporal em desenvolvimento de adolescentes, e medidas cerebrais estruturais correlacionadas com o funcionamento cognitivo. MÉTODO: Dezenove adolescentes (12 do sexo masculino, sete do sexo feminino, variação de idade: 11-17a, média: 15a 8m, desvio padrão: 1a 7m, mediana: 15a 11m) com lesão cerebral traumática (LCT) foram incluídos. A espessura cortical dos lobos frontais e temporais foi avaliada usando ressonância magnética funcional. Correlacionamos a espessura cortical de regiões pré-frontais-temporais com a idade, tempo após a lesão, e funcionamento neurocognitivo, e comparamos estes resultados com uma coorte controle pareada, sem LCT. RESULTADOS: Encontramos córtex pré-frontal (p=0,039) e temporal (p=0,002) mais finos em adolescentes com LCT. Além disso, efeito significativo da idade foi observado na espessura pré-frontal (r=-0,75, p=0,003) e temporal (r=-0,66, p=0,013) em adolescentes com desenvolvimento típico, mas não nos com LCT. A função executiva (mensurada com o questionário Inventário de pontuação do comportamento da Função Executiva, com menor pontuação indicando maior funcionamento) foi correlacionada com a espessura cortical pré-frontal em adolescentes com desenvolvimento típico (r=0,72, p=0,009). Tendências opostas para as correlações entre espessura cortical e função executiva foram encontradas nas coortes com LCT e controle. INTERPRETAÇÃO: A maturação estrutural em adolescentes com desenvolvimento típico se correlaciona com o desenvolvimento functional: quanto mais velho o adolescente, mais fino o córtex e melhor a função executiva. Em adolescents com LCT observamos a tendência oposta, que foi significantemente diferente do grupo controle: quanto mais fino o córtex pré-frontal e temporal, pior a função cognitiva.

Impaired rich club and increased local connectivity in children with traumatic brain injury: Local support for the rich?

Recent evidence has shown the presence of a "rich club" in the brain, which constitutes a core network of highly interconnected and spatially distributed brain regions, important for high-order cognitive processes. This study aimed to map the rich club organization in 17 young patients with moderate to severe TBI (15.71 ± 1.75 years) in the chronic stage of recovery and 17 age- and gender-matched controls. Probabilistic tractography was performed on diffusion weighted imaging data to construct the edges of the structural connectomes using number of streamlines as edge weight. In addition, the whole-brain network was divided into a rich club network, a local network and a feeder network connecting the latter two. Functional outcome was measured with a parent questionnaire for executive functioning. Our results revealed a significantly decreased rich club organization (p values < .05) and impaired executive functioning (p < .001) in young patients with TBI compared with controls. Specifically, we observed reduced density values in all three subnetworks (p values < .005) and a reduced mean strength in the rich club network (p = .013) together with an increased mean strength in the local network (p = .002) in patients with TBI. This study provides new insights into the nature of TBI-induced brain network alterations and supports the hypothesis that the local subnetwork tries to compensate for the biologically costly subnetwork of rich club nodes after TBI.

Concurrent Cortical Representations of Function- and Size-Related Object Affordances: An fMRI Study.

Previous work has shown that the perception of a graspable object may automatically potentiate actions that are tailored to specific action-related features of the object (e.g., its size) and may be related to its immediate grasping as well as to its long-term, functional use. We investigated the neural correlates of function- and size-related object affordances that may be concurrently potentiated by a graspable object. Participants were lying in a MR scanner holding a large switch in one hand and a small switch in the other hand. They passively attended a large or a small object with clearly separated functional and graspable end that was displayed centrally at an average angle of 45 degrees. Participants responded to the direction of an arrow that was overlaid on the object after a mean period of 1,000 ms after object onset and was pointing to the left or to the right with equal probability. Response times were shorter when the arrow pointed to the functional end of the object and when the responses were made with the switch that was congruent to the size of the perceived object. A clear distinction was found in the representation of function- and size-related affordances; the former was represented in the posterior parietal cortex and the latter in prefrontal, premotor, and primary sensorimotor cortices. We conclude that different aspects of object-directed actions may be automatically potentiated by individual object features and are represented in distinct brain areas.

Rehabilitation of visuospatial neglect by prism adaptation: effects of a mild treatment regime. A randomised controlled trial.

Closely examining the effects, optimal regime and time window of prism adaptation (PA) promotes guidelines for effective rehabilitation practice. The effects of short-term repetitive PA on spatial neglect manifestations were evaluated in patients with heterogeneous post-stroke delays, using a digital Visuospatial Neglect Test Battery. Subsequently, potential differences in PA effects between acute, subacute or chronic neglect were explored. A multicentre randomised controlled trial was conducted in 43 right-hemisphere neglect patients. They were treated with a mild PA regime: seven sessions of experimental or placebo prism training over 7-12 days. The outcome measures were diverse neglect variables related to peripersonal navigation, visual extinction, visuospatial memory, bisection, cancellation, drawing and visual search. The treatment effects were assessed after a short and a long time interval. Two to 24 hours after PA, conventional effects were found for drawing and centred bisection, and novel effects for peripersonal visuospatial navigation, visual extinction, and non-motor memory (with caution). No effects were found for visual search times and cancellation. The assessments after three months were still indicative of PA benefits for navigational, drawing and memory functions. PA did not prove to be more effective in acute, subacute or chronic patients. The extension of effects is theoretically framed within the debate about the levels of cognitive processing that are impacted by PA. Clinical suggestions are formulated regarding PA implementation in neglect treatment.

Mental imagery of positive and neutral memories: A fMRI study comparing field perspective imagery to observer perspective imagery.

Imagery perspective can influence what information is recalled, processing style, and emotionality; however, the understanding of possible mechanisms mediating these observed differences is still limited. We aimed to examine differences between memory recall from a field perspective and observer perspective at the neurobiological level, in order to improve our understanding of what is underlying the observed differences at the behavioral level. We conducted a fMRI study in healthy individuals, comparing imagery perspectives during recall of neutral and positive autobiographical memories. Behavioral results revealed field perspective imagery of positive memories, as compared to observer perspective, to be associated with more positive feelings afterwards. At the neurobiological level, contrasting observer perspective to field perspective imagery was associated with greater activity, or less decrease relative to the control visual search task, in the right precuneus and in the right temporoparietal junction (TPJ). Greater activity in the right TPJ during an observer perspective as compared to field perspective could reflect performing a greater shift of perspective and mental state during observer perspective imagery than field perspective imagery. Differential activity in the precuneus may reflect that during observer perspective imagery individuals are more likely to engage in (self-) evaluative processing and visuospatial processing. Our findings contribute to a growing understanding of how imagery perspective can influence the type of information that is recalled and the intensity of the emotional response. Observer perspective imagery may not automatically reduce emotional intensity but this could depend on how the imagined situation is evaluated in relation to the self-concept.

Brain Connectomics of Visual-Motor Deficits in Children with Developmental Coordination Disorder.

OBJECTIVE: To extend preliminary findings on associated white matter deficits and structural connectivity in children with developmental coordination disorder (DCD). STUDY DESIGN: Diffusion magnetic resonance imaging-based tractography was used to identify abnormal microstructural properties of specific sensorimotor white matter tracts in 21 children with DCD between 8 and 10 years of age and 20 age- and sex-matched typically developing controls. Graph theoretical analyses were applied to evaluate whole brain connectomics. Associations were also calculated between the tractography/connectome results and visual-motor performance, as measured with the Beery-Buktenica Developmental Test of Visual Motor Integration. RESULTS: Significant positive correlations were obtained between visual-motor trace scores and fractional anisotropy (FA) in the retrolenticular limb of the internal capsule within the group with DCD. Moreover, lower FA in sensorimotor tracts and altered structural connectivity were observed for children with DCD. Compared with controls, subjects with DCD showed decreases in clustering coefficient, and global and local efficiency, suggesting weaker structural network segregation and integration. The degree of decreased global efficiency was significantly associated with poor visual-motor tracing outcomes, above and beyond FA reductions. Specifically, nodal efficiency at the cerebellar lobule VI and right parietal superior gyrus were found significant predictors to discriminate between children with DCD and those with typical development. CONCLUSIONS: Specific white matter alterations and network topology features associate with visual-motor deficits and DCD diagnosis indicating the clinical potential of diffusion magnetic resonance imaging-based metrics for diagnosing DCD.

Transcervical Carotid Stenting With Dynamic Flow Reversal Demonstrates Embolization Rates Comparable to Carotid Endarterectomy.

PURPOSE: To evaluate a series of patients treated electively with carotid endarterectomy (CEA), transfemoral carotid artery stenting with distal filter protection (CASdp), and transcervical carotid stenting with dynamic flow reversal (CASfr) monitored continuously with transcranial Doppler (TCD) during the procedure to detect intraoperative embolization rates. METHODS: Thirty-four patients (mean age 67.6 years; 24 men) with significant carotid stenosis underwent successful TCD monitoring during the revascularization procedure (10 CEA, 8 CASdp, and 16 CASfr). Ipsilateral microembolic signals were segregated into 3 phases: preprotection (until internal carotid artery cross-shunted or clamped if no shunt was used, filter deployed, or flow reversal established), protection (until clamp/shunt was removed, filter retrieved, or antegrade flow reestablished), and postprotection (after clamp/shunt or filter removal or restoration of normal flow). RESULTS: CASdp showed higher embolization rates than CEA or CASfr in the preprotection phase (p<0.001). In the protection phase, CASdp was again associated with more embolization compared with CEA and CASfr (p<0.001). In the postprotection phase, no differences between the revascularization therapies were observed. CASfr and CEA did not show significant differences in intraoperative embolization during any of the phases. CONCLUSION: TCD recordings demonstrated a significant reduction in embolization to the brain during transcervical carotid artery stent placement with the use of dynamic flow reversal compared to transfemoral CAS using distal filters. No significant differences in microembolization could be detected between CEA and CASfr. The observed lower embolization rates and lack of adverse events suggest that transcervical CAS with dynamic flow reversal is a promising technique and may be the preferred method when performing CAS.

Perioperative Embolization Load and S-100ß Do Not Predict Cognitive Outcome after Carotid Revascularization.

BACKGROUND: Cognitive changes after carotid revascularization have been reported in 10-20% of patients. The etiology of cognitive impairments remains largely unknown. This study evaluates the predictive value of S-100ß serum values and perioperative microembolization on cognition after carotid revascularization. METHODS: Forty-six patients with significant carotid stenosis underwent carotid endarterectomy (CEA, n = 26), transfemoral carotid artery stenting with distal protection (CASdp, n = 10), or transcervical carotid stenting with dynamic flow reversal (CASfr, n = 10). Twenty-six matched vascular patients without carotid stenosis were recruited as controls. All patients underwent comprehensive cognitive testing on the day before and 1 month after carotid revascularization. S-100ß analysis was performed in 31 cases pre-, peri-, and 2, 6, and 24 hr after carotid surgery, and in 25 patients transcranial Doppler monitoring was done during surgery. RESULTS: In the 3 treatment groups similar transient increases in S-100ß values were observed. CASdp was associated with a higher embolic load than CEA and CASfr, while CEA was also associated with less microembolization than CASfr. Cognitive improvement or deterioration could not be predicted by S-100ß or perioperative embolic load for any of the investigated cognitive domains. CONCLUSIONS: Cognitive deterioration could not be predicted using perioperative embolic load and S-100ß changes. A similar inverted u-curve of the S-100ß levels was observed in the 3 groups and may be caused by impairment in the blood-brain barrier during intervention, and not due to cerebral infarction. Distal protection CAS is associated with a higher embolic load than transcervical CAS using dynamic flow reversal and CEA, but the long-term impact of this higher embolic load is yet unknown. Perfusion-related measures seem promising in their ability to predict cognitive decline.

Functional connectivity associated with hand shape generation: Imitating novel hand postures and pantomiming tool grips challenge different nodes of a shared neural network.

Clinical research suggests that imitating meaningless hand postures and pantomiming tool-related hand shapes rely on different neuroanatomical substrates. We investigated the BOLD responses to different tasks of hand posture generation in 14 right handed volunteers. Conjunction and contrast analyses were applied to select regions that were either common or sensitive to imitation and/or pantomime tasks. The selection included bilateral areas of medial and lateral extrastriate cortex, superior and inferior regions of the lateral and medial parietal lobe, primary motor and somatosensory cortex, and left dorsolateral prefrontal, and ventral and dorsal premotor cortices. Functional connectivity analysis revealed that during hand shape generation the BOLD-response of every region correlated significantly with every other area regardless of the hand posture task performed, although some regions were more involved in some hand postures tasks than others. Based on between-task differences in functional connectivity we predict that imitation of novel hand postures would suffer most from left superior parietal disruption and that pantomiming hand postures for tools would be impaired following left frontal damage, whereas both tasks would be sensitive to inferior parietal dysfunction. We also unveiled that posterior temporal cortex is committed to pantomiming tool grips, but that the involvement of this region to the execution of hand postures in general appears limited. We conclude that the generation of hand postures is subserved by a highly interconnected task-general neural network. Depending on task requirements some nodes/connections will be more engaged than others and these task-sensitive findings are in general agreement with recent lesion studies.

Neurodevelopment and behavior after transcatheter versus surgical closure of secundum type atrial septal defect.

OBJECTIVE: To assess the neuropsychological and behavioral profiles of school-aged children treated for atrial septal defect, secundum type (ASD-II) with open-heart surgery or catheterization. STUDY DESIGN: Patients (n = 48; mean age, 9 years, 3 months) and a matched healthy group (mean age, 9 years, 2 months) were evaluated with a shortened intelligence scale (Wechsler Intelligence Scale for Children, third edition, Dutch version) and a developmental neuropsychological test battery (Developmental Neuropsychological Assessment, second edition, Dutch version). Parents completed behavioral checklists (Achenbach Child Behavior Checklist for Children aged 6-18). Hospitalization variables were retrieved from medical files for studying associations with long-term neurodevelopment. RESULTS: Compared with the healthy matched controls, patients treated for ASD-II had significantly lower scores on subtasks underlying such Developmental Neuropsychological Assessment, second edition, Dutch version domains as Attention and Executive Functioning, Language, Working Memory, Sensorimotor Functioning, Social Cognition, and Visuospatial Information Processing. Only subtle differences, mainly in Visuospatial Information Processing, were found between the surgical repair and transcatheter repair groups. Socioeconomic status, longer hospital stay, and larger defect size were associated with neurocognitive outcome measures. Parents of patients reported more thought problems, posttraumatic stress problems, and lower school performance compared with parents of healthy peers. CONCLUSION: After treatment for ASD-II, children display a range of neuropsychologic difficulties that may increase their risk for learning problems and academic underachievement. Differences related to treatment were not found. Our results suggest that neurodevelopmental and behavioral follow-up at school age is warranted in this group.