Matilda Papathanasiou

Optic nerve sonography in the diagnostic evaluation of adult brain injury

IntroductionThe optic nerve sheath diameter (ONSD) may be increased in brain-injured patients, especially children, with intracranial hypertension. We investigated whether measurements of ONSD correlated with simultaneous noninvasive and invasive measurements of the intracranial pressure (ICP) in brain-injured adults.MethodsSeventy-six critical care patients (58 males; 47 ± 18 years old) were included in the study. Fifty patients suffered from brain injury, whereas 26 had no intracranial pathology and served as control individuals. Initially, brain-injured patients were evaluated clinically (Glasgow Coma Scale) and using a semiquantitative (I to VI) neuroimaging scale (Marshall Scale). Thereafter, the patients were divided into those with moderate (Marshall Scale = I and Glasgow Coma Scale > 8 [n = 18]) and severe (Marshall Scale = II to VI and Glasgow Coma Scale ≤8 [n = 32]) brain injury. All patients underwent noninvasive measurement of the ICP (estimated ICP) by transcranial Doppler sonography, and synchronous ONSD measurements by optic nerve sonography. Finally, invasive ICP measurement using an intraparenchymal catheter was performed in patients with severe brain injury.ResultsONSD and estimated ICP were both significantly increased (6.1 ± 0.7 mm and 26.2 ± 8.7 mmHg, respectively; P < 0.0001) in patients with severe brain injury as compared with patients with moderate brain injury (4.2 ± 1.2 mm and 12.0 ± 3.6 mmHg) and compared with control individuals (3.6 ± 0.6 mm and 10.3 ± 3.1 mmHg). Furthermore, in patients with severe brain injury the ONSD measurements were strongly correlated with estimated ICP values (r = 0.80, P < 0.0001) as well as with the neuroimaging scale results (r = 0.82, P < 0.001). In the patients with severe brain injury, ONSD measurements correlated with invasive ICP values (r = 0.68, P = 0.002). The best cut-off value of ONSD for predicting elevated ICP was 5.7 mm (sensitivity = 74.1% and specificity = 100%).ConclusionONSD measurements correlate with noninvasive and invasive measurements of the ICP, and with head computed tomography scan findings in brain-injured adults. Hence, optic nerve sonography may serve as an additional diagnostic tool that could alert clinicians to the presence of elevated ICP, whenever invasive ICP evaluation is contraindicated and/or is not available. This trial is International Standard Randomised Controlled Trial Number registered (ISRCTN 91941687).

Lateralization of brain activity during lower limb joints movement. An fMRI study.

Studies of unilateral finger movement in right-handed subjects have shown asymmetrical patterns of activation in primary motor cortex and subcortical regions. In order to investigate the existence of an analogous pattern during lower limb joints movements, functional magnetic resonance imaging (fMRI) was used. Eighteen healthy, right leg dominant volunteers participated in a motor block design study, performing unilateral right and left repetitive knee, ankle and toes flexion/extension movements. Aiming to relate lower limb joints activation to the well-described patterns of finger movement, serial finger-to-thumb opposition was also assessed. All movements were auditory paced at 72 beats/min (1.2 Hz). Brain activation during movement of the nondominant joints was more bilateral than during the same movement performed with the dominant joints. Finger movement had a stronger lateralized pattern of activation in comparison with lower limb joints, implying a different functional specialization. Differences were also evident between the joints of the lower limb. Ankle and toes movements elicited the same extend of MR signal change in the majority of the examined brain regions, whereas knee joint movement was associated with a different pattern. Finally, lateralization index in primary sensorimotor cortex and basal ganglia was significantly affected by the main effect of dominance, whereas the lateralization index in cerebellum was significantly affected by the joint main effect, demonstrating a lateralization index increase from proximal to distal joints.

Anterior Cruciate Ligament Deficiency Causes Brain Plasticity A Functional MRI Study

Background The mechanoreceptors located in anterior cruciate ligament (ACL) constitute an afferent source of information toward the central nervous system. It has been proposed that ACL deficiency causes a disturbance in neuromuscular control, affects central programs and consequently the motor response resulting in serious dysfunction of the injured limb. Purpose The objective of this study was to investigate whether chronic anterior cruciate ligament injury causes plastic changes in brain activation patterns. Study Design Case control study; Level of evidence, 3. Methods Seventeen right leg–dominant male participants with chronic anterior cruciate ligament deficiency and 18 matched healthy male participants with no special sport or habitual physical activity participated in this study. Patient selection criteria comprised a complete right unilateral anterior cruciate ligament rupture ≥6 months before testing. Brain activation was examined by using functional magnetic resonance imaging technique (1.5-T scanner). Results Results show that patients with anterior cruciate ligament deficiency had diminished activation in several sensorimotor cortical areas and increased activation in 3 areas compared with controls: presupplementary motor area, posterior secondary somatosensory area, and posterior inferior temporal gyrus. Conclusion The current study reveals that anterior cruciate ligament deficiency can cause reorganization of the central nervous system, suggesting that such an injury might be regarded as a neurophysiologic dysfunction, not a simple peripheral musculoskeletal injury. This evidence could explain clinical symptoms that accompany this type of injury and lead to severe dysfunction. Understanding the pattern of brain activation after a peripheral joint injury such as anterior cruciate ligament injury lead to new standards in rehabilitation and motor control learning with a wide application in a number of clinical and research areas (eg, surgical procedures, patient re-education, athletic training, etc).

Lower limb sensorimotor network: Issues of somatotopy and overlap

Functional magnetic resonance imaging (fMRI) was used (1) to describe the pattern of whole brain activity during motion of isolated joints of the lower limb, (2) to examine the somatotopic organization of lower limb joint representations in the primary sensorimotor cortex and the anterior lobe of the cerebellum and 3) to quantify the degree of overlap between these lower limb joint activations. Eighteen healthy, right leg dominant volunteers participated in a motor block-design study, performing repetitive knee, ankle and toes flexion/extension movements. In order to relate lower limb joints activation to the well-described patterns of finger movement, serial finger-to-thumb opposition was also assessed. All movements were auditory paced at 72 beats/min (1.2 Hz). Isolated lower limb joints movement activated a distributed sensorimotor network, including primary and non-primary sensorimotor areas. Although a large overlap was evident in primary sensorimotor cortex (SM1) and cerebellum representations of the three lower limb joints, a somatotopic arrangement was recognizable with reference to center of mass coordinates of each individual joint in the above areas. Detection of active brain regions during movement of the lower limb joints is feasible with fMRI although a carefully optimized methodology protocol is required.

Cervical spine ROM measurements: optimizing the testing protocol by using a 3D ultrasound‐based motion analysis system

The aim of this study was to evaluate the intra- and inter-examiner reliability and validity of neck range of motion (ROM) measurements. Thirty-five healthy subjects were assessed in all neck movements from two initial positions, sitting and standing, actively (open and closed eyes) and passively by using a 3D ultrasound-based motion analysis device (Zebris). Three tests were employed to assess intra-examiner reliability and two examiners used for the inter-examiner reliability. X-rays in neck flexion and extension were used to validate the Zebris system. The standing position yielded higher intraclass correlation coefficient (ICC) values (>0.86) with less error [smallest detectable difference (SDD) < 13.8%] than sitting (ICC > 0.79, SDD < 14%). Passive assessment of neck ROM presented better reproducibility than active assessment with open or closed eyes in both positions. The inter-examiner reliability was moderate (ICC = 0.43-0.68). The correlation between the Zebris system and X-rays was high in both flexion and extension movements. The results showed that the most reliable protocol for assessment of neck ROM is a passive measurement in the standing position. The measurements were well validiated against X-rays and the experience of the investigators must be considered before any comparison among studies is employed.

Association of serum BDNF levels with hippocampal volumes in first psychotic episode drug-naive schizophrenic patients

Evidence suggests that hippocampal volumetric abnormalities are present in first-episode schizophrenia. The hippocampus contains the highest brain levels of neurotrophic factors, which are major determinants of neuronal plasticity. Brain-derived neurotrophic factor (BDNF) influences neuronal survival, differentiation, synaptogenesis, and maintenance and is also correlated with neuronal activation in the hippocampus. BDNF is also involved in the development and modulation of dopaminergic-related systems. Alterations of serum BDNF levels have been shown in a number of studies with first episode patients with schizophrenia, probably reflecting an association between BDNF and the pathogenesis of the disorder. In the present study we investigated the correlation between serum BDNF levels and hippocampal volumes in a sample of first episode drug-naïve patients with schizophrenia (FEP) and healthy control subjects. We found that hippocampal volume (HV) was decreased in FEP patients. Corrected right HV of FEP patients were significantly smaller compared to corrected right HVs of healthy subjects. The serum BDNF levels in the sample of FEP patients was significantly reduced compared to the healthy subjects. A significant positive association was found between serum BDNF and the corrected right HV in the group of patients such that the smaller the HV, the more reduced the serum BDNF levels. (Pearson r=0.452, p=0.045). Our findings indicate that low serum BDNF levels are associated with reduction in HV at the onset of schizophrenia and may further support the theory of a neuroprogressive-neurotoxic reaction associated with the onset of psychosis.

A magnetic resonance imaging study of hippocampal, amygdala and subgenual prefrontal cortex volumes in major depression subtypes: Melancholic versus psychotic depression

BACKGROUND Volumetric studies examining brain structure in depression subtypes are limited and inconclusive. The aim of the current study was to compare the volumes of brain regions previously implicated in depression among patients with melancholic major depressive disorder (MDD), patients with psychotic MDD and normal controls. METHODS Twenty two patients with melancholic MDD, 17 with psychotic MDD and 18 normal controls were included in the study. Hippocampal (HV), amygdala (AV), anterior (ASCV) and posterior (PSCV) subgenual cortex volumes were measured on magnetic resonance volumetric images. RESULTS There were no volumetric differences between patients with melancholic and psychotic subgroups. We identified larger AVs and smaller left ASCVs in both patient groups compared to controls with medium to large effect sizes. Regression analysis revealed that AVs were predicted by the presence of depression, late depression-onset, insomnia and left hippocampal tail volume in patients, but not in controls. There were no differences in HVs, right ASCVs and PSCVs across the 3 groups. LIMITATIONS Small sample size, a possible inclusion of paracingulate gyrus in ASCV and PSCV tracings, significant differences in education level and medication status are discussed as limitations. CONCLUSIONS Diagnostically delineated melancholic and psychotic MDD patients do not differ in medial temporal and cingulate volumes. However, significant volumetric differences were detected between both patient-groups and controls.

A Longitudinal Study of Alterations of Hippocampal Volumes and Serum BDNF Levels in Association to Atypical Antipsychotics in a Sample of First-Episode Patients with Schizophrenia

Background Schizophrenia is associated with structural and functional abnormalities of the hippocampus, which have been suggested to play an important role in the formation and emergence of schizophrenia syndrome. Patients with schizophrenia exhibit significant bilateral hippocampal volume reduction and progressive hippocampal volume decrease in first-episode patients with schizophrenia has been shown in many neuroimaging studies. Dysfunction of the neurotrophic system has been implicated in the pathophysiology of schizophrenia. The initiation of antipsychotic medication alters the levels of serum Brain Derived Neurotrophic Factor (BDNF) levels. However it is unclear whether treatment with antipsychotics is associated with alterations of hippocampal volume and BDNF levels. Methods In the present longitudinal study we investigated the association between serum BDNF levels and hippocampal volumes in a sample of fourteen first-episode drug-naïve patients with schizophrenia (FEP). MRI scans, BDNF and clinical measurements were performed twice: at baseline before the initiation of antipsychotic treatment and 8 months later, while the patients were receiving monotherapy with second generation antipsychotics (SGAs). Results We found that left hippocampal volume was decreased (corrected left HV [t = 2.977, df = 13, p = .011] at follow-up; We also found that the higher the BDNF levels change the higher were the differences of corrected left hippocampus after 8 months of treatment with atypical antipsychotics (Pearson r = 0.597, p = 0.024). Conclusions The association of BDNF with hippocampal volume alterations in schizophrenia merits further investigation and replication in larger longitudinal studies.

Large Diameter Limbs for Dilated Common Iliac Arteries in Endovascular Aneurysm Repair. Is It Safe

In this prospective study we examined whether dilated common iliac arteries (CIAs) can provide a safe distal seal in endovascular aneurysm repair (EVAR) with the use of bifurcated stent grafts with large diameter limbs. Sixteen patients with 26 dilated CIAs with a diameter of ≥6 mm who were offered EVAR using stent grafts with large diameter limbs were included in the study (Group A). Forty-two patients who also underwent EVAR without iliac dilatation, matched for age, sex and surgical risk were used for comparison (controls-Group B). In group A mean CIA diameter was 18.2 mm (16–28) and mean abdominal aortic aneurysm (AAA) diameter was 6.87 ± 1.05 cm; mean age was 77.2 ± 4.8 yrs (67–81). Mean follow-up was 33.6 months (2.8 yrs). CIA diameter changes and development of endoleaks were assessed by CT angiography (CTA). Overall iliac dilatation was present in 16/58 of our patients (27.6%). In 10 patients dilatation was bilateral (17.3%). Partial or complete flow to the internal iliac artery (IIA) territories was preserved in all patients post-EVAR. On follow-up, stable caliber of the dilated CIAs was observed in 21 patients (84%), enlargement of 1mm in 3 (16%), and failure of the distal attachment in 1 (6.2%). Compared to the control group there was no statistical significance in the incidence of complications. Dilated common iliac arteries provide a safe distal seal in patients who have undergone EVAR, thus obviating the need for additional endovascular procedures and sparing flow in the IIA vascular bed.

Porencephaly and psychosis: a case report and review of the literature

BackgroundMalformations of the cerebral cortex are often associated with developmental delay and psychoses. Porencephaly is a rare congenital disorder of central nervous system involving a cyst or a cavity filled with cerebrospinal fluid, in brains parenchyma.Case presentationWe present a 25 years old woman with her first psychotic episode. She also suffers from porencephaly in the frontotemporal lobes region. It is emphasized that the two consistently abnormal brain regions in schizophrenia research had significant damage in this patient since birth. There is a total of only five cases of schizencephaly or porencephaly associated with psychosis in the scientific literature. Their clinical characteristics as well as the imaging results are described.ConclusionIt is unclear if porencephaly and psychosis concur by chance or are causally related. The area where the porencephalic cysts appear seems to be of relevance. This case highlights the need for further research.