25 research outputs found

    Relative K-stability for Kähler manifolds

    Get PDF
    We study the existence of extremal Kähler metrics on Kähler manifolds. After introducing a notion of relative K-stability for Kahler manifolds, we prove that Kähler manifolds admitting extremal Kähler metrics are relatively K-stable. Along the way, we prove a general Lp lower bound on the Calabi functional involving test configurations and their associated numerical invariants, answering a question of Donaldson. When the Kähler manifold is projective, our definition of relative K-stability is stronger than the usual definition given by Székelyhidi. In particular our result strengthens the known results in the projective case (even for constant scalar curvature Kähler metrics), and rules out a well known counterexample to the "naïve" version of the Yau-Tian-Donaldson conjecture in this setting

    Whole-scalp EEG mapping of somatosensory evoked potentials in macaque monkeys

    Get PDF

    Whole-scalp EEG mapping of somatosensory evoked potentials in macaque monkeys

    Get PDF
    High-density scalp EEG recordings are widely used to study whole-brain neuronal networks in humans non-invasively. Here, we validate EEG mapping of somatosensory evoked potentials (SSEPs) in macaque monkeys (Macaca fascicularis) for the long-term investigation of large-scale neuronal networks and their reorganisation after lesions requiring a craniotomy. SSEPs were acquired from 33 scalp electrodes in five adult anaesthetized animals after electrical median or tibial nerve stimulation. SSEP scalp potential maps were identified by cluster analysis and identified in individual recordings. A distributed, linear inverse solution was used to estimate the intracortical sources of the scalp potentials. SSEPs were characterised by a sequence of components with unique scalp topographies. Source analysis confirmed that median nerve SSEP component maps were in accordance with the somatotopic organisation of the sensorimotor cortex. Most importantly, SSEP recordings were stable both intra- and interindividually. We aim to apply this method to the study of recovery and reorganisation of large-scale neuronal networks following a focal cortical lesion requiring a craniotomy. As a prerequisite, the present study demonstrated that a 300-mm2 unilateral craniotomy over the sensorimotor cortex necessary to induce a cortical lesion, followed by bone flap repositioning, suture and gap plugging with calcium phosphate cement, did not induce major distortions of the SSEPs. In conclusion, SSEPs can be successfully and reproducibly recorded from high-density EEG caps in macaque monkeys before and after a craniotomy, opening new possibilities for the long-term follow-up of the cortical reorganisation of large-scale networks in macaque monkeys after a cortical lesion

    Spinal epidural hematomas: personal experience and literature review of more than 1000 cases

    No full text
    OBJECTIVE The goal of this study was to identify factors that contribute to the formation of acute spinal epidural hematoma (SEH) by correlating etiology, age, site, clinical status, and treatment with immediate results and long-term outcomes. METHODS The authors reviewed their series of 15 patients who had been treated for SEH between 1996 and 2012. In addition, the authors reviewed the relevant international literature from 1869 (when SEH was first described) to 2012, collecting a total of 1010 cases. Statistical analysis was performed in 959 (95%) cases that were considered valid for assessing the incidence of age, sex, site, and clinical status at admission, correlating each of these parameters with the treatment results. Statistical analysis was also performed in 720 (71.3%) cases to study the incidence of etiological factors that favor SEH formation: coagulopathy, trauma, spinal puncture, pregnancy, and multifactorial disorders. The clinical status at admission and long-term outcome were studied for each group. Clinical status was assessed using the Neuro-Grade (NG) scale. RESULTS The mean patient age was 47.97 years (range 0-91 years), and a significant proportion of patients were male (60%, p < 0.001). A bimodal distribution has been reported for age at onset with peaks in the 2nd and 6th decades of life. The cause of the SEH was not reported in 42% of cases. The etiology concerned mainly iatrogenic factors (18%), such as coagulopathy or spinal puncture, rather than noniatrogenic factors (29%), such as genetic or metabolic coagulopathy, trauma, and pregnancy. The etiology was multifactorial in 11.1% of cases. The most common sites for SEH were C-6 (n = 293, 31%) and T-12 (n = 208, 22%), with maximum extension of 6 vertebral bodies in 720 cases (75%). At admission, 806 (84%) cases had moderate neurological impairment (NG 2 or 3), and only lumbar hematoma was associated with a good initial clinical neurological status (NG 0 or 1). Surgery was performed in 767 (80%) cases. Mortality was greater in patients older than 40 years of age (9%; p < 0.01). Sex did not influence any of these data (p > 0.05). CONCLUSIONS Factors that contribute to the formation of acute SEH are iatrogenic, not iatrogenic, or multifactorial. The treatment of choice is surgery, and the results of treatment are influenced by the patient's clinical and neurological status at admission, age, and the craniocaudal site

    Pain in Postsurgical Orthopedic Rehabilitation: A Multicenter Study

    No full text
    Objective.\u2002 The aim of this study was to quantify and characterize pain in patients undergoing lower limb postsurgical orthopedic rehabilitation and to investigate the impact of pain in slowing or interrupting their rehabilitation. Design.\u2002 The study was designed as a multicenter cross-sectional study. Setting.\u2002 The study was set in rehabilitation departments of the Don Gnocchi Foundation. Subjects.\u2002 The study subjects were the inpatients attending rehabilitation. Interventions.\u2002 There were no interventions used in the study. Outcome Measures.\u2002 Pain intensity was measured with a numeric rating scale (NRS); pain characteristics were assessed with the McGill Pain Questionnaire and the ID Pain (able to discriminate nociceptive from neuropathic pain). Quality of life (QoL) was measured with the Short Form 36 Health Status Survey. A semi-structured questionnaire on pain occurrence, impact, and management was administered by the physiotherapist in charge of the patients and by the physician. Results.\u2002 We studied 139 patients, 82% of whom complained of at least moderate pain (NRS 65 3). According to ID pain, 45.6% patients complained of probable (33.8%) or highly probable (11.8%) neuropathic pain. A higher pain intensity was significantly related to the probability of having neuropathic pain (P < 0.001). Patients with more severe pain reported lower physical and mental QoL scores. In 38.6% of cases, pain interfered with the rehabilitation process, and in 18.5% it was the cause of physical therapy discontinuation. Conclusions.\u2002 In light of the high occurrence and intensity of pain in the sample, and of the significant impact on the rehabilitation program, clinicians should pay more attention to pain, especially neuropathic pain, in postsurgical patients. Tailored pain pharmacological therapy could possibly improve patient compliance during the rehabilitation process and enhance long-term outcomes

    Occurrence and predictors of the fatigue in high-grade glioma patients

    No full text
    A better knowledge of the fatigue could be of the greatest importance for the high-grade glioma (HGG) patients, who are a unique and vulnerable population. The aim of this study was to evaluate the occurrence and the predictors of the fatigue in HGG patients, using a specific fatigue scale. The study was designed as a cross-sectional study. The study population included sixty-seven consecutive outpatients with HGG. We used these measures: Brief Fatigue Inventory, Karnofsky Performance Scale, Functional Independence Measure, Brief Psychiatric Rating Scale and Psychological Distress Inventory and SF-36, EORTC QLQ-30 and EORTC QLQ-BN20 for quality of life (QoL). Sixteen out of sixty-seven (23.9 %) patients were affected by Anaplastic Astrocytoma and 51/67 (76.1 %) by Glioblastoma Multiforme. About one-third (36.2 %) of patients had a clinically relevant fatigue (Brief Fatigue Inventory 653). In regression analysis, physical and mental aspects of QoL were statistically significant related with fatigue (p < 0.01 and p < 0.02, respectively). Our data underlined the relevant occurrence of fatigue in HGG patients and support the development of further studies exploring a tailored rehabilitation program
    corecore