In-vivo digital volume correlation via magnetic resonance imaging: Application to positional brain shift and deep tissue injury

This thesis aims to investigate the complexity of the physiological mechanical response of soft tissues, providing rich datasets for the verification of clinical systems limiting or preventing tissue injury. A thorough understanding of the sagging of the brain tissue under the effect of gravity (positional brain shift, PBS) is paramount for the design of an effective intra-operative correction of surgical trajectories; rich measurements of the response of the buttock to sitting loads can help the verification of computational models to couple with clinical measures for the prevention and control of pressure ulcers. Digital volume correlation (DVC) consists in measuring the local differences between scans depicting the deformed and undeformed stages of a sample under load, facilitating the characterisation of the mechanical response of the sample. The use of DVC in-vivo is limited, due to the limited quality of the scans constrained by the acquisition setting. Accuracy of three deformable registration methods was first assessed after optimisation against biomechanically plausible ground truths generated via finite element simulations. Against the simulation of PBS, the best accuracy achieved was of one order of magnitude smaller than the resolution of the images. For the simulation of deformations of the buttock due to sitting, optimal accuracy was around 10% of the average deformation fields applied. The best performing methods alongside their optimal parameter sets were then used to perform in-vivo measurements on real magnetic resonance scans of two separate datasets of healthy subjects. For PBS, the study revealed the need for intervention- and Abstract iv patient-specific correction of surgical trajectories given the effect of head geometry and orientation on the shift. For the deformation of the buttock due to sitting, the measure�ments gave a three-dimensional depiction of the local and global pattern of deformation, which results were previously limited to thickness or surface measurements

SHREC'20: Shape correspondence with non-isometric deformations

Estimating correspondence between two shapes continues to be a challenging problem in geometry processing. Most current methods assume deformation to be near-isometric, however this is often not the case. For this paper, a collection of shapes of different animals has been curated, where parts of the animals (e.g., mouths, tails & ears) correspond yet are naturally non-isometric. Ground-truth correspondences were established by asking three specialists to independently label corresponding points on each of the models with respect to a previously labelled reference model. We employ an algorithmic strategy to select a single point for each correspondence that is representative of the proposed labels. A novel technique that characterises the sparsity and distribution of correspondences is employed to measure the performance of ten shape correspondence methods

Fabrication of a positional brain shift phantom through the utilization of the frozen intermediate hydrogel state

Synthetic models (phantoms) of the brain-skull system are useful tools for the study of surgical events that are otherwise difficult to study directly in humans. To date, very few studies can be found which replicate the full anatomical brain-skull system. Such models are required to study the more global mechanical events that can occur in neurosurgery, such as positional brain shift. Presented in this work is a novel workflow for the fabrication of a biofidelic brain-skull phantom which features a full hydrogel brain with fluid-filled ventricle/fissure spaces, elastomer dural septa and fluid-filled skull. Central to this workflow is the utilization of the frozen intermediate curing state of an established brain tissue surrogate, which allows for a novel moulding and skull installation approach that permits a much fuller recreation of the anatomy. The mechanical realism of the phantom was validated through indentation testing of the phantom's brain and simulation of the supine to prone brain shift event, while the geometric realism was validated through magnetic resonance imaging. The developed phantom captured a novel measurement of the supine to prone brain shift event with a magnitude that accurately reproduces that seen in the literature

Full-field MRI measurements of in-vivo positional brain shift reveal the significance of intra-cranial geometry and head orientation for stereotactic surgery

Positional brain shift (PBS), the sagging of the brain under the effect of gravity, is comparable in magnitude to the margin of error for the success of stereotactic interventions (∼ 1 mm). This non-uniform shift due to slight differences in head orientation can lead to a significant discrepancy between the planned and the actual location of surgical targets. Accurate in-vivo measurements of this complex deformation are critical for the design and validation of an appropriate compensation to integrate into neuronavigational systems. PBS arising from prone-to-supine change of head orientation was measured with magnetic resonance imaging on 11 young adults. The full-field displacement was extracted on a voxel-basis via digital volume correlation and analysed in a standard reference space. Results showed the need for target-specific correction of surgical targets, as a significant displacement ranging from 0.52 to 0.77 mm was measured at surgically relevant structures. Strain analysis further revealed local variability in compressibility: anterior regions showed expansion (both volume and shape change), whereas posterior regions showed small compression, mostly dominated by shape change. Finally, analysis of correlation demonstrated the potential for further patient- and intervention-specific adjustments, as intra-cranial breadth and head tilt correlated with PBS reaching statistical significance

DEVELOPING PERSPECTIVE TAKING SKILL THROUGH EDU-GAMING: AN EXPLORATORY STUDY

Several researchers have shown that edugames may be considered as an innovative educational tool to promote learners’ acquisition of basic and specialized skills (Aiello et al., 2016; Ghanouni et al., 2021; Lau, Wang, & Wang, 2020; Maliverni et al., 2017; Sibilio, 2017; Vallefuoco et al., 2022). Nonetheless, only few educational tools have been expressly created and studied to develop Perspective Taking (PT) skill. This is surprising when considering that PT skill represents a milestone for the development of several competencies, including those in Science, Technology, Engineering and Mathematics (STEM) and socio-emotional competencies (McCurdy et al., 2020; Grimaldi, 2019). Indeed, a deficit in PT is considered a vulnerability factor for cognitive, emotional and social developmental domains (Viola, Zappalà, & Sibilio, 2022). Thus, it is deemed necessary to develop resources that educators may adopt in order to foster the acquisition of PT skill since childhood, especially in case of deficits in socio-emotional skills or autism spectrum disorders. In Italy, Schoolcam (Di Tore, Aiello, Sibilio, & Berthoz, 2020) has been created to serve this purpose. To date, the edugame has been tested both with adults and children to explore possible relationships between the scores obtained when using Schoolcam and those measured using other validated tests, such us the PTSOT test. Users are assessed on three tasks: the first two assess PT skill at two distinct levels of difficulty. The third task assesses Mental Rotation Ability, defined as a skill which is partially independent of PT. Results confirmed that the edugame may be considered a reliable tool to assess the level of development of PT skill, but it also needed to undergo some modifications: users asked for more attractive avatars, one more activity was included to assess PT without social landmarks, everything was set to remotely interact with the edugame using tablets and pushbuttons (Di Tore et al., 2020). Based on these premises, the aim of this paper is that of exploring the impact of playing the new version of Schoolcam, called “Virtual Classroom”, on developing social and perspective taking skills through the identification of standard points for the edugame. This objective also moves from a research interest embedded in a larger project whose purpose is to explore how the use of this edugame may foster the development of the aforementioned skill in inclusive classrooms, also attended by learners with autism spectrum disorders, and socio pathological cases among adults (Di Tore et al., 2020; Viola, Zappalà, & Sibilio, 2022; Zappalà, Viola, & Aiello, 2022). The study involved a convenience sample of 116 future support teachers enrolled in the specialization course for educational support activities for pupils with disabilities at the University of Salerno. Data was examined for normality using percentile scores and descriptive statistics. Future studies will examine the possibility of using the tasks of the edugame as a training tool to favor the development of PT to investigate if the edugame may be used as an educational resource aimed at enhancing PT and socio-emotional skills

Neurochemical characterization of the cerebellar-recipient motor thalamicterritory in the macaque monkey

The immunoarchitectonics of the macaque motor thalamus was analysed to look for a possible neurochemical characterization of thalamic territories, which were not definable cytoarchitectonically, associated with different functional pathways. Thalamic sections from 15 macaque monkeys were processed for visualization of calbindin (CB), parvalbumin (PV), calretinin (CR) and SMI-32 immunoreactivity (ir). PV-, CR- and SMI-32ir distributions did not show any clear correlation with known functional subdivisions. In contrast, CBir distribution reliably defined two markedly distinct motor thalamic territories, one characterized by high cell and neuropil CBir (CB-positive territory), the other by very low cell and neuropil CBir (CB-negative territory). These two neurochemically distinct compartments, the CB-negative and the CB-positive territories, appear to correspond to the cerebellar- and basal ganglia-recipient territories, respectively. To verify the possible correspondence of the CB-negative territory with the cerebellar-recipient sector of the motor thalamus, we compared the distribution of cerebello-thalamic projections with the distribution of CBir in two monkeys. The distribution of cerebellar afferent terminals was similar to that reported from previous reports and in line with the notion that in the motor thalamus the cerebellar-recipient territory does not respect cytoarchitectonic boundaries. Comparison with CB immunoarchitecture showed very close correspondence in the motor thalamus between the distribution of the anterograde labeling and the CB-negative territory, suggesting that the CB-negative territory represents the architectonic counterpart of the cerebellar-recipient territory. CB immunostaining may therefore represent a helpful tool for describing the association between thalamocortical projections and the basal ganglia or the cerebellar loops and for establishing possible homologies between the motor thalamus of non-human primates and humans. © 2005 Federation of European Neuroscience Societies

A pilot study on the use of interferon beta-1a in early Alzheimer's disease subjects

Despite the fact that multiple sclerosis (MS) and Alzheimer's disease (AD) share common neuroimmunological features, interferon beta 1a (IFN beta 1a), the well-established treatment for the prevention of disease progression and cognitive decline in MS patients, has never been used in AD. We evaluated the safety and efficacy of IFN beta 1a in subjects affected by mild-to-moderate AD in a double-blind, randomized, placebo-controlled, multicenter pilot study. Forty-two early Alzheimer's patients were randomized to receive either a 22 mcg subcutaneous injection of IFN beta 1a or placebo three times per week. A treatment period of 28 weeks was followed by 24 weeks of observation. IFN beta 1a was well tolerated and adverse events were infrequent and mild to moderate. Although not statistically significant, a reduction in disease progression during follow-up was measured in IFN beta 1a-treated patients by the Alzheimer's Disease Assessment Scale cognitive subscale. Interestingly, the treatment group showed significant improvements in the Instrumental Activities of Daily Living and Physical Self-maintenance Scale. This study suggests that IFN beta 1a is safe and well tolerated in early AD patients, and its possible beneficial role should be further investigated in larger studies.Despite the fact that multiple sclerosis (MS) and Alzheimer's disease (AD) share common neuroimmunological features, interferon beta 1a (IFNβ1a), the well-established treatment for the prevention of disease progression and cognitive decline in MS patients, has never been used in AD. We evaluated the safety and efficacy of IFNβ1a in subjects affected by mild-to-moderate AD in a double-blind, randomized, placebo-controlled, multicenter pilot study. Forty-two early Alzheimer's patients were randomized to receive either a 22 mcg subcutaneous injection of IFNβ1a or placebo three times per week. A treatment period of 28 weeks was followed by 24 weeks of observation. IFNβ1a was well tolerated and adverse events were infrequent and mild to moderate. Although not statistically significant, a reduction in disease progression during follow-up was measured in IFNβ1a-treated patients by the Alzheimer's Disease Assessment Scale cognitive subscale. Interestingly, the treatment group showed significa