Laterality Index Research Articles

A three-classification model for identifying migraine with right-to-left shunt using lateralization of functional connectivity and brain network topology: a resting-state fMRI study

IntroductionRight-to-left shunting has been significantly associated with migraine, although the neural mechanisms remain complex and not fully elucidated. The aim of this study was to investigate the variability of brain asymmetry in individuals with migraine with right-to-left shunting, migraine without right-to-left shunting and normal controls using resting-state fMRI technology and to construct a three-classification model.MethodsFirstly, asymmetries in functional connectivity and brain network topology were quantified to laterality indices. Secondly, the laterality indices were employed to construct a three-classification model using decision tree and random forest algorithms. Ultimately, through a feature score analysis, the key brain regions that contributed significantly to the classification were extracted, and the associations between these brain regions and clinical features were investigated.ResultsOur experimental results showed that the initial classification accuracy reached 0.8961. Subsequently, validation using an independent sample set resulted in a classification accuracy of 0.8874. Further, after expanding the samples by the segmentation strategy, the classification accuracies were improved to 0.9103 and 0.9099. Additionally, the third sample set yielded a classification accuracy of 0.8745. Finally, 9 pivotal brain regions were identified and distributed in the default network, the control network, the visual network, the limbic network, the somatomotor network and the salience/ventral attention network.DiscussionThe results revealed distinct lateralization features in the brains of the three groups, which were closely linked to migraine and right-to-left shunting symptoms and could serve as potential imaging biomarkers for clinical diagnosis. Our findings enhanced our understanding of migraine and right-to-left shunting mechanisms and offered insights into assisting clinical diagnosis.

Asymmetry of attentive networks contributes to adult Attention-deficit/hyperactivity disorder (ADHD) pathophysiology.

Diffusion imaging studies in Attention-deficit/hyperactivity disorder (ADHD) have revealed alterations in anatomical brain connections, such as the fronto-parietal connection known as superior longitudinal fasciculus (SLF). Studies in neurotypical adults have shown that the three SLF branches (SLF I, II, III) support distinct brain functions, such as attention and inhibition; and that their pattern of lateralization is associated with attention performance. However, most studies in ADHD have investigated the SLF as a single bundle and in children; thus, the potential contribution of the lateralization of the SLF branches to adult ADHD pathophysiology remains to be elucidated. We used diffusion-weighted spherical deconvolution tractography to dissect the SLF branches in 60 adults with ADHD (including 26 responders and 34 non-responders to methylphenidate, MPH) and 20 controls. Volume and hindrance modulated orientational anisotropy (HMOA), which respectively reflect white matter macro- and microstructure, were extracted to calculate the corresponding lateralization indices. We tested whether neurotypical controls differed from adults with ADHD, and from treatment response groups in sensitivity analyses; and investigated associations with clinico-neuropsychological profiles. All the three SLF branches were lateralized in adults with ADHD, but not in controls. The lateralization of theSLFI HMOA was associated with performance at the line bisection, not that of the SLF II volume as previously reported in controls. Further, an increased left-lateralization of the SLF I HMOA was associated with higher hyperactivity levels in the ADHD group. Thus, an altered asymmetry of the SLF, perhaps especially of the dorsal branch, may contribute to adult ADHD pathophysiology.

Olfactory Dysfunction and Limbic Hypoactivation in Temporal Lobe Epilepsy.

The epileptogenic network in temporal lobe epilepsy (TLE) contains structures of the primary and secondary olfactory cortex such as the piriform and entorhinal cortex, the amygdala, and the hippocampus. Olfactory auras and olfactory dysfunction are relevant symptoms of TLE. This study aims to characterize olfactory function in TLE using olfactory testing and olfactory functional magnetic resonance imaging (fMRI). We prospectively enrolled 20 individuals with unilateral TLE (age 45 ± 20 years [mean ± SD], 65% female, 90% right-handed) and 20 healthy individuals (age 33 ± 15 years [mean ± SD], 35% female, 90% right-handed). In the TLE group, the presumed seizure onset zone was left-sided in 75%; in 45% of the individuals with TLE limbic encephalitis was the presumed etiology; and 15% of the individuals with TLE reported olfactory auras. Olfactory function was assessed with a Screening Sniffin' Sticks Test (Burkhart, Wedel, Germany) during a pre-assessment. During a pre-testing, all individuals were asked to rate the intensity, valence, familiarity, and associated memory of five different odors (eugenol, vanillin, phenethyl alcohol, decanoic acid, valeric acid) and a control solution. During the fMRI experiment, all individuals repeatedly smelled eugenol (positively valenced odor), valeric acid (negatively valenced odor), and the control solution and were asked to rate odor intensity on a five-point Likert scale. We acquired functional EPI sequences and structural images (T1, T2, FLAIR). Compared to healthy individuals, individuals with TLE rated the presented odors as more neutral (two-sided Mann-Whitney U tests, FDR-p < 0.05) and less familiar (two-sided Mann-Whitney U tests, FDR-p < 0.05). fMRI data analysis revealed a reduced response contrast in secondary olfactory areas (e.g., hippocampus) connected to the limbic system when comparing eugenol and valeric acid in individuals with TLE when compared with healthy individuals. However, no lateralization effect was obtained when calculating a lateralization index by the number of activated voxels in the olfactory system (two-sided Mann-Whitney U test; U = 176.0; p = 0.525). TLE is characterized by olfactory dysfunction and associated with hypoactivation of secondary olfactory structures connected to the limbic system. These findings contribute to our understanding of the pathophysiology of TLE. This study was preregistered on OSF Registries (www.osf.io).

Identification of asymmetrical abnormalities in functional connectivity and brain network topology for migraine sufferers: A preliminary study based on resting-state fMRI data

Research on the neural mechanisms underlying brain asymmetry in patients with migraine patients using fMRI is insufficient. This study proposed using lateralized algorithms for functional connectivity and brain network topology and investigated changes in their lateralization in patients with migraine. In study 1, laterality indices of functional connectivity (LFunctionCorr) and brain network topological properties (LBetweennessCentrality, LDegree, and LStrength) were defined. Differences between migraineurs and normal subjects were compared at whole-brain, half-brain, and region levels. In study 2, laterality indices were used to classify migraine and were validated using independent samples and the segment method for repeatability. In study 3, abnormal brain regions related to migraine were extracted based on the classification results and differences analysis. Study 1 found no significant differences related to in for migraine at the whole-brain level; however, significant differences were identified at the half-brain level for the hemispheric lateralization of the LFunctionCorr, while 11 significantly different brain regions were also identified at the brain region level. Furthermore, the classification accuracy in study 2 was 0.9366. With repeated validation, the accuracy reached 0.8561. Furthermore, after extending the samples according to the segmentation strategy, the classification accuracies were improved to 0.9408 and 0.8585. Study 3 identified 10 crucial brain regions with asymmetrical specificity based on laterality indices distributed across the visual network, the frontoparietal control network, the default mode network, the salience/ventral attention network and the limbic system. The results revealed novel insights and avenues for research into the mechanisms of migraine asymmetry and showed that the laterality indices could be used as a potential diagnostic imaging marker for migraine.

Spherical-deconvolution informed filtering of tractograms changes laterality of structural connectome

Diffusion MRI-driven tractography, a non-invasive technique that reveals how the brain is connected, is widely used in brain lateralization studies. To improve the accuracy of tractography in showing the underlying anatomy of the brain, various tractography filtering methods were applied to reduce false positives. Based on different algorithms, tractography filtering methods are able to identify the fibers most consistent with the original diffusion data while removing fibers that do not align with the original signals, ensuring the tractograms are as biologically accurate as possible. However, the impact of tractography filtering on the lateralization of the brain connectome remains unclear. This study aims to investigate the relationship between fiber filtering and laterality changes in brain structural connectivity. Three typical tracking algorithms were used to construct the raw tractography, and two popular fiber filtering methods(SIFT and SIFT2) were employed to filter the tractography across a range of parameters. Laterality indices were computed for six popular biological features, including four microstructural measures (AD, FA, RD, and T1/T2 ratio) and two structural features (fiber length and connectivity) for each brain region. The results revealed that tractography filtering may cause significant laterality changes in more than 10% of connections, up to 25% for probabilistic tracking, and deterministic tracking exhibited minimal laterality changes compared to probabilistic tracking, experiencing only about 6%. Except for tracking algorithms, different fiber filtering methods, along with the various biological features themselves, displayed more variable patterns of laterality change. In conclusion, this study provides valuable insights into the intricate relationship between fiber filtering and laterality changes in brain structural connectivity. These findings can be used to develop improved tractography filtering methods, ultimately leading to more robust and reliable measurements of brain asymmetry in lateralization studies.

Impact of Cortisol-Cosecretion on Adrenal Venous Sampling Results in Primary Aldosteronism: Study of 225 Cases

Background/Objectives: Mild autonomous cortisol secretion (MACS) can coexist with primary aldosteronism (PA). The purpose of our study was to evaluate whether (MACS) influences parameters analyzed during adrenal venous sampling (AVS) in patients with PA. Methods: Patients with PA from the SPAIN-ALDO Registry and the German Conn’s Registry with available 1 mg-dexamethasone suppression test (DST) and AVS were included. MACS was defined as a post-DST cortisol &gt; 1.8 µg/dL in the absence of specific signs and symptoms of Cushing’s syndrome. Results: Two-hundred and twenty-five patients were included, 98 (43.6%) of whom had concomitant MACS. The mean age was 54 ± 10 years and 37.3% were women. AVS was performed by simultaneous catheterization of both adrenal veins and analysis of basal samples in 157 patients (69.8%), with both basal and post-ACTH samples in 15 patients (6.7%), and during continuous ACTH infusion in 53 patients (23.6%). AVS was considered technically unsuccessful in 40 cases (17.8%), suggesting unilateral secretion in 106 (47.1%) and bilateral secretion in 79 (35.1%). We did not find significant differences in the percentage of unilateral and bilateral results, cortisol, corrected aldosterone, or selectivity indices in the dominant and non-dominant veins, nor in the lateralization index or the contralateral suppression index between patients with and without MACS. They also had similar rates of surgical treatment and biochemical and clinical response. Conclusions: Although pathophysiological reasoning suggests that MACS could hinder AVS identification of unilateral forms of PA, our data suggest that such interference, if it exists, is of moderate clinical relevance.

Enhancing non-invasive pre-surgical evaluation through functional connectivity and graph theory in drug-resistant focal epilepsy

BackgroundEpilepsy, characterized as a network disorder, involves widely distributed areas following seizure propagation from a limited onset zone. Accurate delineation of the epileptogenic zone (EZ) is crucial for successful surgery in drug-resistant focal epilepsy. While visual analysis of scalp electroencephalogram (EEG) primarily elucidates seizure spreading patterns, we employed brain connectivity techniques and graph theory principles during the pre-ictal to ictal transition to define the epileptogenic network. MethodCortical sources were reconstructed from 40-channel scalp EEG in five patients during pre-surgical evaluation for focal drug-resistant epilepsy. Temporal Granger connectivity was estimated ten seconds before seizure and at seizure onset. Results have been analyzed using some centrality indices taken from Graph theory (Outdegree, Hubness). A new lateralization index is proposed by taking into account the sum of the most relevant hubness values across left and right regions of interest. ResultsIn three patients with positive surgical outcomes, analysis of the most relevant Hubness regions closely aligned with clinical hypotheses, demonstrating consistency in EZ lateralization and location. In one patient, the method provides unreliable results due to the abundant movement artifacts preceding the seizure. In a fifth patient with poor surgical outcome, the proposed method suggests a wider epileptic network compared with the clinically suspected EZ, providing intriguing new indications beyond those obtained with traditional electro-clinical analysis. ConclusionsThe proposed method could serve as an additional tool during pre-surgical non-invasive evaluation, complementing data obtained from EEG visual inspection. It represents a first step toward a more sophisticated analysis of seizure onset based on connectivity imbalances, electrical propagation, and graph theory principles.

Explainable artificial intelligence on safe balance and its major determinants in stroke patients

This study develops explainable artificial intelligence for predicting safe balance using hospital data, including clinical, neurophysiological, and diffusion tensor imaging properties. Retrospective data from 92 first-time stroke patients from January 2016 to June 2023 was analysed. The dependent variables were independent mobility scores, i.e., Berg Balance Scales with 0 (45 or below) vs. 1 (above 45) measured after three and six months, respectively. Twenty-nine predictors were included. Random forest variable importance was employed for identifying significant predictors of the Berg Balance Scale and testing its associations with the predictors, including Berg Balance Scale after one month and corticospinal tract diffusion tensor imaging properties. Shapley Additive Explanation values were calculated to analyse the directions of these associations. The random forest registered a higher or similar area under the curve compared to logistic regression, i.e., 91% vs. 87% (Berg Balance Scale after three months), 92% vs. 92% (Berg Balance Scale after six months). Based on random forest variable importance values and rankings: (1) Berg Balance Scale after three months has strong associations with Berg Balance Scale after one month, Fugl-Meyer assessment scale, ipsilesional corticospinal tract fractional anisotropy, fractional anisotropy laterality index and age; (2) Berg Balance Scale after six months has strong relationships with Fugl-Meyer assessment scale, Berg Balance Scale after one month, ankle plantar flexion muscle strength, knee extension muscle strength and hip flexion muscle strength. These associations were positive in the SHAP summary plots. Including Berg Balance Scale after one month, Fugl-Meyer assessment scale or ipsilesional corticospinal tract fractional anisotropy in the random forest will increase the probability of Berg Balance Scale after three months being above 45 by 0.11, 0.08, or 0.08. In conclusion, safe balance after stroke strongly correlates with its initial motor function, Fugl-Meyer assessment scale, and ipsilesional corticospinal tract fractional anisotropy. Diffusion tensor imaging information aids in developing explainable artificial intelligence for predicting safe balance after stroke.

Brain imaging and clinical outcome of embodied VR-BCI training in chronic stroke patients: a longitudinal pilot study

ABSTRACT Introduction Restorative Brain–Computer Interfaces (BCIs) provide an alternative non-muscular channel for stroke patients lacking volitional movement by enhancing sensorimotor rhythm modulation through motor imagery (MI). MI practice can be augmented with embodied feedback via virtual reality (VR). However, the clinical impact of embodied VR-BCI training remains under-explored. Methods This study examines the effects of embodied VR-BCI training on brain activity patterns (measured through EEG and fMRI) and clinical outcomes (assessed by the Fugl–Meyer Assessment, FMA) in four chronic stroke patients. Over a 3-week MI-BCI intervention, patients performed a bimanual rowing task (NeuRow) in VR. EEG data were used to extract Event-related desynchronization (ERD) and lateralization indices, while fMRI data focused on the primary motor (M1) and supplementary motor (SMA) regions of interest. Results Results indicated that all patients significantly induced ERD power, though the affected side exhibited reduced ERD compared to baseline during contralateral MI. Post-intervention, significant ERD differences from both hemispheres were observed, with decreased ERD correlating with no clinical improvement. Patients showing decreased ERD lateralization had no FMA score improvement. Activity within ipsilesional M1 and SMA correlated with FMA scores. Conclusions The findings suggest a relationship between brain activity and clinical outcomes, highlighting that increased ERD lateralization is associated with clinical improvement.

Correlation between the biomechanical characteristics and stability of the 143D movement during the balance phase in competitive Tai Chi.

To explore the biomechanical factors affecting the stability of athletes in the 143D balance phase of competitive Tai Chi. The Vicon 3D motion capture system, Kistler 3D force platform, and Noraxon surface electromyography (sEMG) system were used to measure the joint angle, joint moment, center of gravity, ground reaction force, and sEMG data of athletes. The stability index was then calculated according to the formula. Pearson's or Spearman's correlation tests were used to analyze the associations between the biomechanical factors and stability index. (1) Medial lateral stability index (MLSI): A significant negative correlation was found between the ankle inversion angle of the supporting leg (SL) and MLSI (p < 0.05). (2) Anterior posterior stability index (APSI): Significant negative correlations were observed between the ankle intorsion angle, integrated electromyography (iEMG) of the gastrocnemius, and muscle contribution rates of the tibialis anterior, external oblique, and gastrocnemius of the non-supporting leg (NL) with the APSI (p < 0.05). The ankle dorsiflexion moment, iEMG of the rectus femoris and tibialis anterior, muscle contribution rate of the biceps femoris, and root mean-squared (RMS) amplitude of the gluteus maximus of the SL also showed significant negative correlations with the APSI (p < 0.05). Strong and significant negative correlations were also identified between the hip intorsion angle, iEMG of the tibialis anterior, and RMS amplitude of the rectus femoris of the NL with the APSI (p < 0.01). Further strong and significant negative correlation was also found between the RMS amplitude of the biceps femoris of the SL and APSI (p < 0.01). The knee extorsion angle of the NL was positively correlated with the APSI (p < 0.05). (3) Dynamic postural stability index (DPSI): The knee adduction angle, iEMG of the tibialis anterior, and RMS amplitude of the erector spinae of the NL were significantly positively correlated with the DPSI (p < 0.05). The knee abduction and hip extension moments of the SL were also significantly positively correlated with the DPSI (p < 0.05). The ankle inversion angle of the SL impacts left-right stability, while the NL's hip and ankle intorsion angles, knee extorsion angle, and exertion on the core muscle and SL's main muscles, as well as exertion of specific muscles of the NL affect anterior-posterior stability. The hip extension and knee abduction moments of the SL, knee adduction angle, exertion on the tibialis anterior, and activation of the erector spinae of the NL significantly affect the overall stability of an athlete.

The effect of urea-formaldehyde adhesive modification with diisocyanate-functionalized nanocellulose on the properties of particleboard

In this paper, a nanocrystalline cellulose (NCC) functionalized with 4,4′-diphenylmethane diisocyanate (MDI) was used as a modifier for urea-formaldehyde (UF) adhesive in particleboard production. The applied method of NCC functionalization with diisocyanate has not been previously studied in research on wood-based materials. Chemical structure of MDI-NCC evaluated with Fourier transform infrared spectroscopy (FTIR) demonstrated some significant changes indicating that the functionalization was effective. No change in crystallinity caused by the modification was noted based on the lateral order index and total crystallinity index. Hydrophilicity of NCC was reduced due to the functionalization with MDI. Based on the differential scanning calorimetry (DSC) results, it was found that the reactivity of the resin was improved by the addition of NCC, and moreover, the effect was even more noticeable when the MDI-NCC was introduced. Properties of manufactured particleboards such as density, water absorption and formaldehyde content were not affected by the resin reinforcement. In turn, the modification of NCC with MDI allowed to increase the strength and reduce swelling of the particleboards more significantly than in the case of a neat NCC. It indicates that application of diisocyanate-functionalized NCC has great potential for the use as the UF resin modifier in particleboard production.

An exploratory study of functional brain activity associated with gross motor function improvement in children with unilateral cerebral palsy

ABSTRACT Purpose Identify relations of gross motor function and primary motor cortex (M1) functional activity pre and post gross motor interventions for children with unilateral cerebral palsy (UCP). Methods Thirteen children with UCP completed a gross motor intervention. Pre/post-intervention functional MRI outcomes included the laterality index (LI), activation volume, and spatial overlap of M1 activation during active ankle dorsiflexion. Advanced gross motor function (Challenge) was assessed pre/post-intervention, and 2–6 months later. Bivariate correlations and linear regression assessed relations between neuroimaging and motor function. Results Mean pre-intervention M1 activity was contralateral during dominant (LI = +0.85, SD 0.21) but variable during the affected (LI = +0.43, SD 0.57) ankle dorsiflexion. Changes in motor function and neuroimaging outcomes were not significantly associated. However, smaller affected ankle activation and less spatial overlap between ankle activations pre-intervention predicted Challenge improvements post-intervention (adjusted R2 = 0.74, p = .001.) Conclusions This exploratory study identified pre-intervention neuroimaging predictors of post-intervention improvements in advanced gross motor function.

12293 Dynamic Clinical Evolution: Why Patients Require Long-Term Follow-up Over Time

Abstract Disclosure: A. Attre: None. A. Syeda: None. A. Khan: None. B. Esayag-Tendler: None. Dynamic Clinical Evolution: Why Patients Require Long-Term Follow-up Over Time Introduction Primary Hyperaldosteronism (PHA) is an increasingly recognized cause of secondary hypertension amenable to specific therapy. We describe a case of PHA with change in management trajectory over time. Case A 48-year-old woman was diagnosed with PHA in 2009 based on an aldosterone level of 42.7 ng/dL, plasma renin activity of &amp;lt;0.1 ng/mL/hr, and a low potassium of 3.4 mmol/L. At that time, simultaneous adrenal venous sampling (AVS) had revealed a bilateral etiology of aldosterone excess. Original imaging with CT scan had shown fullness on both adrenal glands, and she was treated with 50mg daily spironolactone. Follow-up with CT scan in 2018 revealed similar imaging phenotype. When she established care with us in 2020, the abdomen MRI revealed a 2.5 cm x 1.9 cm right adrenal nodule. In addition, the blood pressure readings were noted to be high despite increasing doses of spironolactone to 150mg. Her laboratory results revealed aldosterone 151 ng/dL [&amp;lt; 31 ng/dL], cortisol 0.8 µg/dL, plasma renin activity 0.8 ng/mL/hr [0.2 ng/mL/hr - 1.6 ng/mL/hr], ACTH 12.5 pg/mL [7.2 pg/mL - 63.3 pg/mL], normal plasma metanephrine and a normal thyroid panel. A decision was made to repeat AVS in 2023 following Dr. Doppman’s protocol. The patient’s spironolactone was held before AVS and the plasma renin activity before the procedure was 0.4-0.8 ng/mL/hr. Results: Repeat AVS in 2023 showed mean pre-ACTH right to left lateralization index (LI) of 29.9 and mean post-ACTH LI of 9.7 (cutoff &amp;gt;4). This is concordant with the right adrenal nodule noted on imaging. The selectivity index confirmed adequate adrenal venous sampling data. Analysis of our findings confirmed right adrenal excess and left adrenal suppression compared to the IVC results. This patient underwent a laparoscopic right adrenalectomy in 2023. This patient's aldosterone levels were measured two days postoperatively and were found to be 4.2 ng/dL, showing immediate improvement. Six months postoperatively, our patient’s home and clinic blood pressures are in 120s/60s mmHg range without any medications. The aldosterone remains less than 6 ng/dL and the plasma renin activity is no longer low. Her potassium remains around 4.9 mmol/L. Discussion Based on current literature, surgical treatment is preferred when there is a confirmed unilateral cause of PHA. Adrenalectomy is recommended in patients with confirmed unilateral hyperaldosteronism especially when they do not achieve clinical and biochemical goals (renin plasma activity &amp;gt;1 ng/mL/hr, resolution of hypokalemia and optimal BP control) despite the use of MRA at appropriate doses. Suppressed renin is known to be associated with increased cardiovascular morbidity. This case serves as an important example of the need to follow patients long-term because PHA is a dynamic clinical entity that affects quality of life. Presentation: 6/3/2024

287 - Altered reward circuit in adolescents with non-suicidal self-injury: a study on subcortical volume and lateralization index

287 - Altered reward circuit in adolescents with non-suicidal self-injury: a study on subcortical volume and lateralization index

Machine learning localization to identify the epileptogenic side in mesial temporal lobe epilepsy

BackgroundMesial temporal sclerosis (MTS) is the most common pathology associated with drug-resistant mesial temporal lobe epilepsy (mTLE) in adults.Most atrophic hippocampi can be identified using MRI based on standard epilepsy protocols; however, difficulties can arise in cases where sclerotic changes in the hippocampus are subtle or non-epilepsy-specific protocols have been implemented. In such cases, quantitative methods, such as T1-weighted axial series MRIs, are valuable additional tools to complement epilepsy-specific protocols. In the current study, we applied machine learning (ML) techniques to the analysis of brain regions of interest (ROIs), including the hippocampus, thalamus, and cortical areas, to enhance the accuracy of lesion lateralization in MRI. MethodsThis study included 104 patients diagnosed with mTLE, including 55 with lesions on the right side and 49 with lesions on the left side. FreeSurfer software was used to extract features from high-resolution T1-weighted axial brain MRI scans for use in computing lateralization indices (LI) for various brain regions. After using feature selection to pinpoint critical ROIs, the corresponding LI values were used as parameters in training the ML model. ResultsThe proposed ML model demonstrated exceptional performance in the lateralization of mTLE, achieving test accuracy of 92.38 % with an AUROC of 0.97. ConclusionThis study demonstrated the efficacy of ML in detecting instances of MTS from thin-slice T1 images. The proposed method provides valuable insights for surgical planning and treatment. Nonetheless, additional research will be required to enhance the robustness of the model and rigorously validate its effectiveness and applicability in clinical settings.

Assessment of the Gordon lateral rotation index in postoperative rotational evaluation of supracondylar humerus fractures: a study on validity, reliability, and applicability.

Assessment of the Gordon lateral rotation index in postoperative rotational evaluation of supracondylar humerus fractures: a study on validity, reliability, and applicability.

Deformation Characteristics and Influence Factors of Shear Force Lateral Stiffness Matching Index for Non-Rigid Plate Bent Frame Structures

The period ratio and the drift ratio are commonly used as plane regularity control indices for multi-story buildings. However, they fail to reasonably reflect the regularity of lateral force-resisting component configuration and deformation characteristics in non-rigid plate bent frame structures. This study focuses on the analysis of non-rigid single-span bent frames, examining the variation patterns of a suitable regularity index for non-rigid plate bent frame structures, referred to as the shear force lateral stiffness matching index, under various parameters. Additionally, it introduces indices to quantify the deformation response of non-rigid plate bent frame structures, providing a detailed analysis of the impact of factors such as eccentricity, torsional stiffness, and roof slab stiffness on the deformation characteristics of non-rigid plate bent frame structures and the shear force lateral stiffness matching index. The results show that the shear force lateral stiffness matching index can reflect the inconsistency in the horizontal displacement response of lateral force-resisting components caused by deformations in the roof slab. The proposed indices for torsional and bending deformations accurately quantify the roof slab’s deformation response, revealing the horizontal deformation characteristics of lateral force-resisting components in non-rigid frames. When eccentricity is present, the stiffness of the roof slab has a non-monotonic effect on the torsional component of the structural seismic response.

Behavioral laterality in Greater Flamingo (Phoenicopterus roseus)

Abstract From a behavioral adaptation perspective, lateralization in gregarious species likely evolved to maintain cohesiveness among individuals, particularly in behaviors related to social life that require higher levels of cognitive capabilities. Thus, we hypothesized that motor coordination (lateralization) would be observed at the population level rather than at the individual level. To test this hypothesis, we studied population-level laterality in a wild population of Greater Flamingos (Phoenicopterus roseus) during the winter in Eilat, Israel. In November and December 2019, we recorded 176 behaviors in 220 flamingos, observing four behaviors: ‘At rest,’ ‘Vigilant,’ ‘Scratching,’ and ‘Preening’. The laterality indices for ‘At rest’ and ‘Vigilant’ were similar to those of ambidextrous simulated populations, indicating that these behaviors were not lateralized. However, ‘Preening’ and ‘Scratching’ were significantly left-lateralized. We conclude that at the population level, the symmetry of these behaviors results from flock pressure to coordinate population-level behaviors. Furthermore, the mechanism of lateralization is characteristic not only of the local population but of the entire species sensu stricto.

No evidence of altered language laterality in people who stutter across different brain imaging studies of speech and language.

A long-standing neurobiological explanation of stuttering is the incomplete cerebral dominance theory, which refers to competition between two hemispheres for 'dominance' over handedness and speech, causing altered language lateralization. Renewed interest in these ideas came from brain imaging findings in people who stutter of increased activity in the right hemisphere during speech production or of shifts in activity from right to left when fluency increased. Here, we revisited this theory using functional MRI data from children and adults who stutter, and typically fluent speakers (119 participants in total) during four different speech and language tasks: overt sentence reading, overt picture description, covert sentence reading and covert auditory naming. Laterality indices were calculated for the frontal and temporal lobes using the laterality index toolbox running in Statistical Parametric Mapping. We also repeated the analyses with more specific language regions, namely the pars opercularis (Brodmann area 44) and pars triangularis (Brodmann area 45). Laterality indices in people who stutter and typically fluent speakers did not differ, and Bayesian analyses provided moderate to anecdotal levels of support for the null hypothesis (i.e. no differences in laterality in people who stutter compared with typically fluent speakers). The proportions of the people who stutter and typically fluent speakers who were left lateralized or had atypical rightward or bilateral lateralization did not differ. We found no support for the theory that language laterality is reduced or differs in people who stutter compared with typically fluent speakers.

131I]6ß-Iodomethyl-19-norcholesterol SPECT/CT for the Lateralization of Mineralocorticoid Overproduction in Primary Aldosteronism.

In 42 consecutive patients with confirmed primary aldosteronism, molecular imaging has been performed. After dexamethasone suppression of the non-affected adrenal tissue, 37 MBq [131I]6ß-iodomethyl-19-norcholesterol was injected i.v., and SPECT/CT images were taken 7 days later. Based on the visual evaluation of the images by two nuclear medicine specialists, patients with one-sided tracer accumulation underwent adrenalectomy. To identify a SPECT/CT parameter that best characterizes the side difference, the maximum counts and the mean counts of spherical VOIs were analyzed. Of the 42 patients, 24 had one-sided aldosterone overproduction by SPECT/CT. After surgical removal of the involved adrenal, all 24 patients with SPECT/CT-identified unilateral aldosteronism achieved biochemical cure, defined as a normalized potassium level combined with an aldosterone-to-renin ratio ≤ 30. To identify the best measurable parameter of SPECT/CT side difference, the mean counts and maximum counts of a series of spherical VOIs of different diameters were analyzed. The ratio of the mean counts of 3 cm spherical VOIs of the right and left adrenal regions (lateralization index) was the best discriminator; a ratio of ≥1.29 was characteristic of one-sided disease, without overlap between the one-sided and two-sided patient groups. [131I]6ß-iodomethyl-19-norcholesterol SPECT/CT with a count-based image interpretation and side-ratio calculation may be an equipollent non-invasive substitute for adrenal venous sampling in the lateralization of mineralocorticoid overproduction. It reliably identifies unilateral disease and facilitates patients' selection for surgical intervention. If confirmed by others, this functional imaging may replace AVS when lateralization is required for management decisions in primary aldosteronism.