Intravoxel incoherent motion magnetic resonance imaging in the assessment of brain microstructure and perfusion in idiopathic normal-pressure hydrocephalus.

PURPOSE: To determine the relationship between intravoxel incoherent motion (IVIM) MRI parameters and clinical changes post-tap test (TT) in idiopathic normal-pressure hydrocephalus (iNPH) patients. METHODS: Forty-four probable iNPH patients underwent 3 T MRI before and after TT. IVIM parameters were calculated from eight different bilateral regions of interest in basal ganglia, centrum semiovale, and corona radiata. Patients were categorized based on TT response into positive (group 1) and negative (group 2) groups. A Welch two-sample t-test was used to compare differences in D, D*, f, and ADC between the two groups, while a paired t-test was employed to assess the changes within each group before and after TT. These parameters were then correlated with clinical results. RESULTS: In the lenticular and thalamic nuclei, D value was significantly lower in the group 1 compared to group 2 both pre- and post-TT (p = 0.002 and p = 0.007 respectively). Post-TT, the positive response group exhibited a notably reduced D* value (p = 0.012) and significantly higher f values (p = 0.028). In the corona radiata and centrum semiovale, a significant post-TT reduction in D* was observed in the positive response group (p = 0.017). Within groups, the positive response cohort showed a significant post-TT increase in ADC (p < 0.001) and a decrease in D* (p = 0.007). CONCLUSION: IVIM permits the acquisition of important non-invasive information about tissue and vascularization in iNPH patients. Enhanced perfusion in the lenticular and thalamic nuclei may suggest the role of re-established microvascular and glymphatic pathways, potentially elucidating the functional improvement in motor function after TT in iNPH patients.

Effects of age and gender on neural correlates of emotion imagery.

Mental imagery is part of people's own internal processing and plays an important role in everyday life, cognition and pathology. The neural network supporting mental imagery is bottom-up modulated by the imagery content. Here, we examined the complex associations of gender and age with the neural mechanisms underlying emotion imagery. We assessed the brain circuits involved in emotion mental imagery (vs. action imagery), controlled by a letter detection task on the same stimuli, chosen to ensure attention to the stimuli and to discourage imagery, in 91 men and women aged 14-65 years using fMRI. In women, compared with men, emotion imagery significantly increased activation within the right putamen, which is involved in emotional processing. Increasing age, significantly decreased mental imagery-related activation in the left insula and cingulate cortex, areas involved in awareness of ones' internal states, and it significantly decreased emotion verbs-related activation in the left putamen, which is part of the limbic system. This finding suggests a top-down mechanism by which gender and age, in interaction with bottom-up effect of type of stimulus, or directly, can modulate the brain mechanisms underlying mental imagery.

Multisensory mental imagery of fatigue: Evidence from an fMRI study.

Functional imaging experimental designs measuring fatigue, defined as a subjective lack of physical and/or mental energy characterizing a wide range of neurologic conditions, are still under development. Nineteen right-handed healthy subjects (9 M and 10 F, mean age 43.15 ± 8.34 years) were evaluated by means of functional magnetic resonance imaging (fMRI), asking them to perform explicit, first-person, mental imagery of fatigue-related multisensory sensations. Short sentences designed to assess the principal manifestations of fatigue from the Multidimensional Fatigue Symptom Inventory were presented. Participants were asked to imagine the corresponding sensations (Sensory Imagery, SI). As a control, they had to imagine the visual scenes (Visual Imagery, VI) described in short phrases. The SI task (vs. VI task) differentially activated three areas: (i) the precuneus, which is involved in first-person perspective taking; (ii) the left superior temporal sulcus, which is a multisensory integration area; and (iii) the left inferior frontal gyrus, known to be involved in mental imagery network. The SI fMRI task can be used to measure processing involved in mental imagery of fatigue-related multisensory sensations.

Risk Factors of Persistent Hydrocephalus in Children with Brain Tumor: A Retrospective Analysis.

OBJECT: Hydrocephalus is one of the main complications of brain tumors in children, being present in about 50% of cases at the time of the tumor diagnosis and persisting up to 10-40% of cases after surgical resection. This is a single-institution retrospective study on the variables that may predict the need for treatment of persistent hydrocephalus in pediatric patients presenting with a brain tumor. METHODS: Retrospective case note review of 43 newly diagnosed brain tumors in children referred between April 2012 and January 2018 to our regional pediatric neuro-oncology service was carried out. Diagnosis of hydrocephalus was carried out using both preoperative and postoperative MRI to determine Evans' index (EI) and the fronto-occipital horn ratio (FOHR) from each scan. Simple logistic regression was used to analyze categorical variables as appropriate. A p value <0.05 was considered significant. RESULTS: Forty-three children were analyzed, 26 males and 17 females with a median age at diagnosis 10.4 years (IQR: 5.2-13.5). Hydrocephalus was present in 22/43 children (51%) preoperatively; in 8/22 children (36%) with hydrocephalus undergoing tumor resection, hydrocephalus persisted also in the postoperative period. An EI >0.34 (p = 0.028) and an FOHR >0.46 (p = 0.05) before surgery were associated with a higher prevalence of persistent hydrocephalus and therefore to the need for a cerebrospinal fluid drain device in the postoperative phase. CONCLUSION: Preoperative identification of children at risk for developing persistent hydrocephalus would avoid delays in planning the permanent cerebrospinal fluid drain devices. This study finds that an EI >0.34 and an FOHR >0.46 at diagnosis could impact on the therapeutic management of children with hydrocephalus associated with brain tumors. Prospective and larger-scale studies are needed to standardize this approach.

Reduced cortical thickness and increased gyrification in generalized anxiety disorder: a 3 T MRI study.

BACKGROUND: Although the study of the neuroanatomical correlates of generalized anxiety disorder (GAD) is gaining increasing interest, up to now the cortical anatomy of GAD patients has been poorly investigated and still no data on cortical gyrification are available. The aim of the present study is to quantitatively examine the cortical morphology in patients with GAD compared with healthy controls (HC) using magnetic resonance imaging (MRI). To the best of our knowledge, this is the first study analyzing the gyrification patterns in GAD. METHODS: A total of 31 GAD patients and 31 HC underwent 3 T structural MRI. For each subject, cortical surface area (CSA), cortical thickness (CT), gray matter volume (GMV), and local gyrification index (LGI) were estimated in 19 regions of interest using the Freesurfer software. These parameters were then compared between the two groups using General Linear Model designs. RESULTS: Compared with HC, GAD patients showed: (1) reduced CT in right caudal middle frontal gyrus (p < 0.05, Bonferroni corrected), (2) hyper-gyrification in right fusiform, inferior temporal, superior parietal and supramarginal gyri and in left supramarginal and superior frontal gyri (p < 0.05, Bonferroni corrected). No significant alterations in CSA and GMV were observed. CONCLUSIONS: Our findings support the hypothesis of a neuroanatomical basis for GAD, highlighting a possible key role of the right hemisphere. The alterations of CT and gyrification in GAD suggest a neurodevelopmental origin of the disorder. Further studies on GAD are needed to understand the evolution of the cerebral morphology with age and during the clinical course of the illness.

Preoperative plasticity in the functional naming network of patients with left insular gliomas.

Plasticity could take place as a compensatory process following brain glioma growth. Only a few studies specifically explored plasticity in patients affected by a glioma invading the left insula; even more, plasticity of the insular cortex in task-based functional language network is almost unexplored. In the current study, we explored potential plasticity in a consecutive series of 22 patients affected by a glioma centered to the left insula, by comparing their preoperative object-naming functional network with that of a group of healthy controls. After having controlled for demographic variables, fMRI results showed that patients vs. controls activated a cluster in the right, contralesional pars triangularis including the Broca's area. On the other hand, controls did not significantly activate any brain region more than patients. At behavioral level, patients retained a generally preserved naming performance as well as a proficient language processing profile. These findings suggest that involvement of language-specific areas in the healthy hemisphere could help compensate for the left, affected insula, thus allowing preservation of the naming functions. Results are commented in relation to lesion site, naming performance, and potential relevance for neurosurgery.

Motor or non-motor speech interference? A multimodal fMRI and direct cortical stimulation mapping study.

We retrospectively analyzed data from 15 patients, with a normal pre-operative cognitive performance, undergoing awake surgery for left fronto-temporal low-grade glioma. We combined a pre-surgical measure (fMRI maps of motor- and language-related centers) with intra-surgical measures (MNI-registered cortical sites data obtained during intra-operative direct electrical stimulation, DES, while they performed the two most common language tasks: number counting and picture naming). Selective DES effects along the precentral gyrus/inferior frontal gyrus (and/or the connected speech articulation network) were obtained. DES of the precentral gyrus evoked the motor speech arrest, i.e., anarthria (with apparent mentalis muscle movements). We calculated the number of shared voxels between the lip-tongue and overt counting related- and silent naming-related fMRI maps and the Volumes of Interest (VOIs) obtained by merging together the MNI sites at which a given speech disturbance was observed, normalized on their mean the values (i.e., Z score). Both tongue- and lips-related movements fMRI maps maximally overlapped (Z = 1.05 and Z = 0.94 for lips and tongue vs. 0.16 and -1.003 for counting and naming) with the motor speech arrest seed. DES of the inferior frontal gyrus, pars opercularis and the rolandic operculum induced speech arrest proper (without apparent mentalis muscle movements). This area maximally overlapped with overt counting-related fMRI map (Z = -0.11 and Z = 0.09 for lips and tongue vs. 0.9 and 0.0006 for counting and naming). Interestingly, our fMRI maps indicated reduced Broca's area activity during silent speech compared to overt speech. Lastly, DES of the inferior frontal gyrus, pars opercularis and triangularis evoked variations of the output, i.e., dysarthria, a motor speech disorder occurring when patients cannot control the muscles used to produce articulated sounds (phonemes). Silent object naming-related fMRI map maximally overlapped (Z = -0.93 and Z = -1.04 for lips and tongue vs. -1.07 and 0.99 for counting and naming) with this seed. Speech disturbances evoked by DES may be thought of as selective interferences with specific recruitment of left inferior frontal gyrus and precentral cortex which are differentiable in terms of the specific interference induced.

Parietal/premotor lesions effects on visuomotor cognition in neuro-oncology patients: A multimodal study.

BACKGROUND: Assessing prior to surgery the functionality of brain areas exposed near the tumor requires a multimodal approach that combines the use of neuropsychological testing and fMRI tasks. Paradigms based on motor imagery, which corresponds to the ability to mentally evoke a movement, in the absence of actual action execution, can be used to test sensorimotor areas and the functionality of mental motor representations. METHODS: The most commonly used paradigm is the Limb Laterality Recognition Task (LLRT), requiring judgments about whether a limb belongs to the left or right side of the body. The group studied included 38 patients with high-grade (N = 21), low-grade (N = 11) gliomas and meningiomas (N = 6) in areas anterior (N = 21) and posterior (N = 17) to the central sulcus. Patients before surgery underwent neuropsychological assessment and fMRI. They performed the LLRT as an fMRI task. Accuracy, and neuroimaging data were collected and combined in a multimodal study. Structural MRI data analyses were performed by subtracting the overlap of volumes of interest (VOIs) plotted on lesions from the impaired patient group vs the overlap of VOIs from the spared group. The fMRI analyses were performed comparing the impaired patients and spared group. RESULTS: In general, patients were within normal limits on many neuropsychological screening tests. Compared with the control group, 17/38 patients had significantly different performance. The subtraction between the VOIs overlay of the impaired patients' group vs. the VOIs overlay of the spared group revealed that the areas maximally involved by lesions in the impaired patients' group were the right postcentral gyrus, right inferior parietal lobe, right supramarginal gyrus, right precentral gyrus, paracentral lobule, left postcentral gyrus, right superior parietal lobe, left inferior parietal lobe, and left superior and middle frontal gyrus. Analysis of the fMRI data showed which of these areas contributes to a correct LLRT performance. The task (vs. rest) in the group comparison (spared vs. impaired patients) activated a cluster in the left inferior parietal lobe. CONCLUSION: Underlying the altered performance at LLRT in patients with lesions to the parietal and premotor areas of the right and left hemispheres is a difference in activation of the left inferior parietal lobe. This region is involved in visuomotor processes and those related to motor attention, movement selection, and motor planning.

Cognitive reserve and individual differences in brain tumour patients.

The aim of the paper is to determine the effects of the cognitive reserve on brain tumour patients' cognitive functions and, specifically, if cognitive reserve helps patients cope with the negative effects of brain tumours on their cognitive functions. We retrospectively studied a large sample of around 700 patients, diagnosed with a brain tumour. Each received an MRI brain examination and performed a battery of tests measuring their cognitive abilities before they underwent neurosurgery. To account for the complexity of cognitive reserve, we construct our cognitive reserve proxy by combining three predictors of patients' cognitive performance, namely, patients' education, occupation, and the environment where they live. Our statistical analysis controls for the type, side, site, and size of the lesion, for fluid intelligence quotient, and for age and gender, in order to tease out the effect of cognitive reserve on each of these tests. Clinical neurological variables have the expected effects on cognitive functions. We find a robust positive effect of cognitive reserve on patients' cognitive performance. Moreover, we find that cognitive reserve modulates the effects of the volume of the lesion: the additional negative impact of an increase in the tumour size on patients' performance is less severe for patients with higher cognitive reserve. We also find substantial differences in these effects depending on the cerebral hemisphere where the lesion occurred and on the cognitive function considered. For several of these functions, the positive effect of cognitive reserve is stronger for patients with lesions in the left hemisphere than for patients whose lesions are in the right hemisphere. The development of prevention strategies and personalized rehabilitation interventions will benefit from our contribution to understanding the role of cognitive reserve, in addition to that of neurological variables, as one of the factors determining the patients' individual differences in cognitive performance caused by brain tumours.

Clinical applicability of arterial spin labeling magnetic resonance imaging in patients with possible idiopathic normal pressure hydrocephalus: A prospective preliminary study.

PURPOSE: idiopathic Normal Pressure Hydrocephalus (iNPH) patients have a global reduction of cerebral blood flow (CBF) and Arterial Spin Label (ASL) MRI allows a global evaluation of CBF without the injection of contrast agents. This work aims to assess the qualitative evaluation agreement of ASL CBF colored maps between different neuroradiologists and by correlating these data to the Tap Test. METHODS: Thirty - seven patients with the diagnosis of possible iNPH were consecutively submitted to a diagnostic MRI on a 1.5 Tesla Magnet before and after the lumbar infusion test and the Tap Test. Twenty - seven patients improved after the Tap Test and were addressed to surgery while 10 patients did not improve. All the MRI examinations included a 3D-Pulsed ASL sequence. Two different neuroradiologists independently reviewed all ASL images. They were asked to give a score (0 not improved; 1 improved) to global perfusion image quality by comparing ASL images obtained after the Tap Test to those obtained before. Comparison between inter- and intra-reader qualitative scores were performed with Cohen's kappa. RESULTS: Inter-reader agreement between the two neuroradiologists showed that qualitative scores were attributed similarly by two readers (k = 0.83). This technique has a good PPV (90.5 %; CI 95 %, 72.7-97.1 %), NPV (50 %; CI 95 %, 34.1-65.6 %), SN (70.37 %; CI 95 %, 49.8-86.2 %) SP (80 %; CI 95 %, 44.4-97.5 %) and accuracy (73 %; CI 95 %, 55.9-86.2 %) when considered in the setting of possible iNPH patients. CONCLUSION: ASL-MRI seems to be a promising non-invasive technique in the preoperative selection of patients affected by possible iNPH.

Neurological disorders in COVID-19: a case of Acute Disseminated Encephalomyelitis in an adult patient.

Different neurological complications associated with the severe acute respiratory syndrome coronavirus (SARS-CoV-2) infection have been widely documented. Acute disseminated encephalomyelitis (ADEM) is a rare immune-mediated demyelinating disorder, described within the spectrum of neurological manifestations of COVID-19. Herein, we describe a case of adult-ADEM presenting with diplopia and slowly progressive ataxia developed one month after SARS-CoV-2 infection. Brain magnetic resonance imaging (MRI) revealed acute multifocal demyelinating lesions throughout the brain. Other possible etiologies have been ruled out. After treatment with high-dose steroids, we observed a progressive clinical and radiological improvement. A 4-months follow-up showed complete clinical recovery. Although extremely rare, ADEM could be associated to SARS-CoV-2 infection and should be considered in the differential diagnosis. Early recognition of this COVID-19 neurological complication, even in the absence of pulmonary involvement, is important to start a prompt immune-modulatory treatment and, consequently, ensure a good outcome.

Incidental low grade glioma in young female: An indolent lesion? A case report and a literature review.

OBJECTIVE: The wide use of brain MRI has led to an increased diagnosis of incidental low-grade gliomas (LGGs). There is no consensus regarding the surgical treatment of incidental LGGs, nor even when we deal with a young woman who wants to plan a pregnancy. We performed a literature review on the topic of cognitive testing and pregnancy in LGGs. Results on the patients' cognitive status are poorly addressed: if, after surgery, neuropsychological deficits were to arise, this would greatly complicate the management of a child by a mother who is an oncological patient, and, moreover, has developed cognitive alterations that may compromise the abilities to look after a baby. We also report the case of a 30-years old woman with a diagnosis of incidental LGG who underwent a first surgery for a right-frontal oligodendroglioma METHODS: The patient underwent two awake surgeries and in both performed the Real Time Neuropsychological Testing (RTNT). We acquired clinical and MRI data. This paper also reports a literature review on the topic of cognitive testing and pregnancy in LGGs highlighting a lack of adequate data about this issue. RESULTS: No deterioration of neuropsychological performances was documented during surgery. During the follow-up, she became pregnant and, despite an increased growth rate of the lesion, she did not accuse any symptom or sign of evolution in high-grade glioma (HGG). She underwent a second awake surgery with RTNT. Performance was maintained within the normal range. CONCLUSIONS: We concluded that, in our experience, pregnancy could induce an increased growth rate of LGG, not influencing the prognosis.

Multidisciplinary Approach to Patients With Metastatic Spinal Cord Compression: A Diagnostic Therapeutic Algorithm to Improve the Neurological Outcome.

Introduction: The morbidity associated with metastatic spinal disease is significant because of spinal cord and/or nerve root compression. The purpose of this paper is to define a diagnostic-therapeutic path for patients with vertebral metastases and from this path to build an algorithm to reduce the devastating consequences of spinal cord compression. Materials and Methods: The algorithm is born from the experience of a primary care center. A spine surgeon, an emergency room (ER) physician, a neuroradiologist, a radiation oncologist, and an oncologist form the multidisciplinary team. The ER physician or the oncologist intercept the patient with symptoms and signs of a metastatic spinal cord compression. Once the suspicion is confirmed, the following steps of the flow-chart must be triggered. The spine surgeon takes charge of the patient and, on the base of the anamnestic data and neurological examination, defines the appropriate timing for magnetic resonance imaging (MRI) in collaboration with the neuroradiologist. From the MRI outcome, the spine surgeon and the radiation oncologist consult each other to define further therapeutic alternatives. If indicated, surgical treatment should precede radiation therapy. The oncologist gets involved after surgery for systemic therapy. Results: In 2021, the Spine and Spinal Cord Surgery department evaluated 257 patients with vertebral metastasis. Fifty-three patients presented with actual or incipient spinal cord compression. Among these, 27 were admitted due to rapid progression of symptoms, neurological deficits and/or spine instability signs. The level was thoracic in 21 cases, lumbar in 4 cases, cervical in 1 case, sacral in 1 case. Fifteen were operated on, 10 of these programmed and 5 in emergency. Discussion: Patients with a history of malignancy can present to the ER or to the oncology department with symptoms that must be correctly framed in the context of a metastatic involvement. Even when there is no previous cancer history, the patient's pain characteristics and clinical signs must be interpreted to yield the correct diagnosis of vertebral metastasis with incipient or current spinal cord compression. The awareness of the alert symptoms and the application of an integrated paradigm consent to frame the patients with spinal cord compression, obtaining the benefits of a homogeneous step-by-step diagnostic and therapeutic path. Early surgical or radiation therapy treatment gives the best hope for preventing the worsening, or even improving, the deficits. Conclusions: Metastatic spinal cord compression can cause neurological deficits compromising quality of life. Treatment strategies should be planned comprehensively. A multidisciplinary approach and the application of the proposed algorithm is of paramount importance to optimize the outcomes of these patients.

Pre-Surgery Cognitive Performance and Voxel-Based Lesion-Symptom Mapping in Patients with Left High-Grade Glioma.

(1) Background: The literature on the effects of high-grade glioma (HGG) growth on cognition is still scarce. (2) Method: A consecutive series of 85 patients with HGG involving the left hemisphere underwent an extended neuropsychological evaluation prior to surgery. Voxel-based lesion-symptom mapping (VLSM) was used to identify regions related to cognitive performance. (3) Results: The patients' mean level of pre-surgery accuracy was overall high. They showed the greatest difficulties in language with tasks such as naming (42.1% of patients impaired on nouns and 61.4% on verbs), reading (36.3% on words and 32.7% on pseudo-words), auditory lexical decisions (43.9%) and writing (41.3%) being most frequently impaired. VLSM analysis revealed anatomically separated areas along the temporal cortex and the white matter related to impairments on the different tasks, with voxels commonly shared by all tasks restricted to a small region in the ventral superior and middle temporal gyrus. (4) Conclusions: High-grade glioma affects cognition; nonetheless, lesions do not cause diffuse deficits but selectively impact the different language sub-domains along the ventral stream and the dorsal stream for language processing.

Acute disseminated encephalomyelitis after SARS-CoV-2 vaccination.

Several central and peripheral nervous system complications associated with the severe acute respiratory syndrome coronavirus (SARS-CoV-2) infection have been recently described. An effective mass vaccination program is necessary to effectively reduce infection spread and, consequently, limit long-term sequelae, including those affecting the nervous system. Nevertheless, as more patients gain access to coronavirus disease 2019 (COVID-19) vaccines, it is important to report potential adverse events. Herein, we report a patient with previous history of post-infectious rhombencephalitis who developed an acute disseminated encephalomyelitis (ADEM) two weeks after being vaccinated for COVID-19.

Stroke in patients with SARS-CoV-2 infection: case series.

BACKGROUND: Italy is one of the most affected countries by the coronavirus disease 2019 (COVID-19). The responsible pathogen is named severe acute respiratory syndrome coronavirus (SARS-CoV-2). The clinical spectrum ranges from asymptomatic infection to severe pneumonia, leading to intensive care unit admission. Evidence of cerebrovascular complications associated with SARS-CoV-2 is limited. We herein report six patients who developed acute stroke during COVID-19 infection. METHODS: A retrospective case series of patients diagnosed with COVID-19 using reverse-transcriptase polymerase chain reaction (RT-PCR) on nasopharyngeal swabs, who developed clinical and neuroimaging evidence of acute stroke during SARS-CoV-2 infection. RESULTS: Six patients were identified (5 men); median age was 69 years (range 57-82). Stroke subtypes were ischemic (4, 67%) and hemorrhagic (2, 33%). All patients but one had pre-existing vascular risk factors. One patient developed encephalopathy prior to stroke, characterized by focal seizures and behavioral abnormalities. COVID-19-related pneumonia was severe (i.e., requiring critical care support) in 5/6 cases (83%). Liver enzyme alteration and lactate dehydrogenase (LDH) elevation were registered in all cases. Four patients (67%) manifested acute kidney failure prior to stroke. Four patients (67%) had abnormal coagulation tests. The outcome was poor in the majority of the patients: five died (83%) and the remaining one (17%) remained severely neurologically affected (mRS: 4). CONCLUSIONS: Both ischemic and hemorrhagic stroke can complicate the course of COVI-19 infection. In our series, stroke developed mostly in patients with severe pneumonia and multiorgan failure, liver enzymes and LDH were markedly increased in all cases, and the outcome was poor.

Sex differences in brain metabolites in anxiety and mood disorders.

Gender differences in mood and anxiety disorders are well-established. However, the neural basis of these differences is not clear yet, especially in terms of brain metabolism. Indeed, although several proton Magnetic Resonance Spectroscopy (¹H MRS) investigations reported different metabolic levels in both depression and anxiety disorders, which have been also linked to symptoms severity and response to treatment, the role of gender on these differences have not been explored yet. Therefore, this study aims at investigating the role of sex in neurometabolic alterations associated with both mood and anxiety disorders. A 3T single-voxel ¹H MRS acquisition of the dorsolateral prefrontal cortex was acquired from 14 Major Depressive Disorder, 10 Generalized Anxiety Disorder (GAD), 11 Panic Disorder (PD), patients and 16 healthy controls (HC). Among males, PD patients showed significantly lower GPC+PC (also observed in GAD+PD) and Glu levels compared to HC. Finally, a significant group x sex interaction effect was observed in the GPC+PC and Glu levels. We proved the presence of an association between sex and brain metabolites in anxiety spectrum.

Cortical bases of elementary deductive reasoning: inference, memory, and metadeduction.

Elementary deduction is the ability of unreflectively drawing conclusions from explicit or implicit premises, on the basis of their logical forms. This ability is involved in many aspects of human cognition and interactions. To date, limited evidence exists on its cortical bases. We propose a model of elementary deduction in which logical inferences, memory, and meta-logical control are separable subcomponents. We explore deficits in patients with left, medial and right frontal lesions, by both studying patients' deductive abilities and providing measures of their meta-logical sensitivity for proof difficulty. We show that lesions to left lateral and medial frontal cortex impair abilities at solving elementary deductive problems, but not so lesions to right frontal cortex. Furthermore, we show that memory deficits differentially affect patients according to the locus of the lesion. Left lateral patients with working memory deficits had defective deductive abilities, but not so left lateral patients with spared working memory. In contrast, in medial patients both deductive and meta-deductive abilities were affected regardless of the presence of memory deficits. Overall, the results are compatible with a componential view of elementary deduction, and call for the elaboration of more fine-grained models of deductive abilities.

The evolution of craniofacial resection: A new workflow for virtual planning in complex craniofacial procedures.

Complex craniofacial surgery has been later to take advantage of computerized planning than traditional maxillofacial procedures. Virtual reality, 3D model navigation, and bioengineering analyses have changed our approach to the surgical planning of craniofacial resection, increasing the benefits of surgery in terms of accuracy while decreasing complication rate. This study introduces a new workflow for 3D reconstruction, virtual model navigation, and alignment analyses, and demonstrates its successful application in a sample of four patients. A case of squamous cell carcinoma of the maxillary and ethmoid sinus in a 62-year-old patient is presented to evaluate the application of the workflow for a combined transfacial and transcranial resection. Results demonstrate that virtual surgical planning was successfully translated into navigational coordinates and reproduced in the operating room. While the literature provides a wide range of applications of virtual planning for traditional maxillofacial procedures, its introduction for complex craniofacial procedures remains difficult. The presented case shows that it is worth investigating the correlation between virtual reality planning and surgical accuracy for craniofacial resection, and related advantages in terms of surgical safety and improved prognosis.

Endoscopically assisted computer-guided repair of internal orbital floor fractures: an updated protocol for minimally invasive management.

BACKGROUND: Performing accurate anatomical reconstruction is a challenging task in the treatment of internal orbital floor fractures. Compared with traditional transcutaneous incisions, endoscopic transmaxillary approaches have the advantage of avoiding complications related to external scars, and provide direct access to the orbital floor. Autogenous bone provides the ideal material for defect reconstruction, but determination of the correct size and shape of the graft is crucial for a stable support. This study introduces a new protocol for the treatment of internal orbital floor fractures that combines endoscopy, virtual reality, and 3D printing. The authors also investigated the impact of computer-aided surgery (CAS) on the overall accuracy of reconstruction in aiming to achieve the triple objective of restoring anatomy, volume, and function. MATERIALS AND METHODS: Fourteen patients with orbital floor fractures were recruited for this study. High-resolution CT scans provided appropriate imaging for detailed orbital floor defect visualization. A virtual reconstruction of the orbital floor defect was developed and a 3D printed template was fabricated to provide intraoperative guidance in the graft harvesting phase, according to the orbital defect. Virtual analyses were conducted to evaluate the accuracy of reconstruction both in terms of graft size and graft orientation. RESULTS: Postoperative CT scans showed that in all cases orbital floor reconstruction was successfully performed, resulting in restoration of the correct globe position. No intraoperative complications occurred. Correspondence of graft size was evaluated using color-coded maps and RMSE, while comparison of angular measurements allowed the authors to relate simulated and actual reconstruction. CONCLUSIONS: Orbital floor reconstruction performed via transmaxillary endoscopy is a safe technique, which allows for detailed visualization of the fracture rim, avoids external scars, and permits an easier reduction of the prolapsed orbital content into the overlying orbital cavity. Virtual planning plays an important role in defining the appropriate geometry of the bone graft and establishing the optimal reconstruction strategy. Our preliminary results indicate that virtual planning and 3D printing should become part of an integrated protocol for the endoscopic treatment of orbital floor fractures.