Cerebellar lesions: is there a lateralisation effect on memory deficits?

Summary: Background. Until recently, neurosurgeons eagerly removed cerebellar lesions without consideration of future cognitive impairment that might be caused by the resection. In children, transient cerebellar mutism after resection has lead to a diminished use of midline approaches and vermis transection, as well as reduced retraction of the cerebellar hemispheres. The role of the cerebellum in higher cognitive functions beyond coordination and motor control has recently attracted significant interest in the scientific community, and might change the neurosurgical approach to these lesions. The aim of this study was to investigate the specific effects of cerebellar lesions on memory, and to assess a possible lateralisation effect. Methods. We studied 16 patients diagnosed with a cerebellar lesion, from January 1997 to April 2005, in the "Centre Hospitalier Universitaire Vaudois (CHUV)”, Lausanne, Switzerland. Different neuropsychological tests assessing short term and anterograde memory, verbal and visuo-spatial modalities were performed pre-operatively. Results. Severe memory deficits in at least one modality were identified in a majority (81%) of patients with cerebellar lesions. Only 1 patient (6%) had no memory deficit. In our series lateralisation of the lesion did not lead to a significant difference in verbal or visuo-spatial memory deficits. Findings. These findings are consistent with findings in the literature concerning memory deficits in isolated cerebellar lesions. These can be explained by anatomical pathways. However, the cross-lateralisation theory cannot be demonstrated in our series. The high percentage of patients with a cerebellar lesion who demonstrate memory deficits should lead us to assess memory in all patients with cerebellar lesion

A 10-year experience in paediatric spontaneous cerebral hemorrhage: which children with headache need more than a clinical examination?

INTRODUCTION: When a child is seen in a clinic with a headache, stroke is certainly not the first on the list of differential diagnoses. In western countries, stroke is typically associated with adults and the elderly. Although rare, haemorrhagic strokes are not exceptional in the paediatric population, as their incidence is around 1/100 000/year. Prompt diagnosis is essential, since delayed treatment may lead to disastrous prognosis in these children. MATERIALS AND METHODS: This is a retrospective review of paediatric cases with spontaneous cerebral haemorrhage that presented in two university hospitals in the last ten years. The experience of these primary and tertiary referral centres comprises 22 consecutive cases that are analysed according to aetiology, presenting symptoms, treatment and outcome. RESULTS: 77% of the children diagnosed with haemorrhagic stroke presented with headaches. 41% of them had a sudden onset, while 9% developed headaches over a period of hours to weeks. While 9% presented only with headaches, the majority had either subtle (diplopia, balance problems) or obvious (focal deficits, unilateral weakness and decreased level of consciousness) concomitant neurological signs. 55% had an arteriovenous malformation (AVM), 18% had an aneurysm and 14% had a cavernous malformation. In 14% the aetiology could not be determined. The majority of haemorrhages (82%) were supratentorial, while 18% bled into the posterior fossa. All children underwent an emergency cerebral CT scan followed by specific investigations. The treatment was dependent on the aetiology as well as the mass effect of the haematoma. In 23% an emergent evacuation of the haematoma was performed. Two children (9%) died, and 75% had a favourable clinical outcome. CONCLUSION: Headaches in children are a common problem, and a small minority may reveal an intracranial haemorrhage with poor prognosis if not treated promptly. Although characterisation of headaches is more difficult in a paediatric population, sudden, unusual or intense headaches should lead to imaging work-up. Any neurological finding, even one as subtle as hemianopsia or dysmetria, should alarm the physician and should be followed by emergency imaging investigation. If the cerebral CT reveals a haemorrhage, the child should be referred immediately to a neurosurgical referral centre without further investigation. The outcome is grim for children presenting in coma with fixed, dilated pupils. The long-term result overall for children after spontaneous intracranial haemorrhage is not dismal and depends critically on specialised management

Automated registration and stitching of multiple 3D ultrasound images for monitoring neonatal intraventricular hemorrhage

Dilatation of the cerebral ventricles is a common condition in preterm neonates with intraventricular hemorrhage (IVH). Post Hemorrhagic Ventricular Dilatation (PHVD) can lead to lifelong neurological impairment caused by ischemic injury due to increased intracranial pressure, and without treatment can lead to death. Previously, we have developed and validated a 3D ultrasound (US) system to monitor the progression of ventricle volumes (VV) in IVH patients; however, many patients with severe PHVD have ventricles so large they cannot be imaged within a single 3D US image. This limits the utility of atlas based segmentation algorithms required to measure VV as parts of the ventricles are in separate 3D US images, and thus, an already challenging segmentation becomes increasingly difficult to solve. Without a more automated segmentation, the clinical utility of 3D US ventricle volumes cannot be fully realized due to the large number of images and patients required to validate the technique in a clinical trials. Here, we describe the initial results of an automated ‘stitching’ algorithm used to register and combine multiple 3D US images of the ventricles of patients with PHVD. Our registration results show that we were able to register these images with an average target registration error (TRE) of 4.25±1.95 mm

Posterior positional plagiocephaly treated with cranial remodeling orthosis.

Since the recommendation that infants sleep in the supine position, there has been an increase in cases of posterior positional plagiocephaly. Even though this condition is a purely cosmetic problem, if it is severe it may affect the child psychologically. Positioning may help in mild or moderate cases, but more active treatment may be necessary in severe cases. A prospective study of 260 children treated by dynamic orthotic cranioplasty for posterior positional plagiocephaly was conducted in Lausanne from 1995 to 2001. Construction of these cranial remodelling helmets is decribed in detail. The treatment lasted 3 months on average, was effective, well tolerated, and had zero morbidity. The ideal period for initiating this therapy is between the ages of 4 and 6 months. The remodelling helmet is a convincing option which can be recommended in infants with posterior positional plagiocephaly whose skull deformity is not satisfactorily corrected by physiotherapy. It should always be used before surgery is considered for patients with recognised positional plagiocephaly in the first year of life

Perceptual Enhancement of Arteriovenous Malformation in MRI Angiography Displays

The importance of presenting medical images in an intuitive and usable manner during a procedure is essential. However, most medical visualization interfaces, particularly those designed for minimally-invasive surgery, suffer from a number of issues as a consequence of disregarding the human perceptual, cognitive, and motor system\u27s limitations. This matter is even more prominent when human visual system is overlooked during the design cycle. One example is the visualization of the neuro-vascular structures in MR angiography (MRA) images. This study investigates perceptual performance in the usability of a display to visualize blood vessels in MRA volumes using a contour enhancement technique. Our results show that when contours are enhanced, our participants, in general, can perform faster with higher level of accuracy when judging the connectivity of different vessels. One clinical outcome of such perceptual enhancement is improvement of spatial reasoning needed for planning complex neuro-vascular operations such as treating Arteriovenous Malformations (AVMs). The success of an AVM intervention greatly depends on fully understanding the anatomy of vascular structures. However, poor visualization of pre-operative MRA images makes the planning of such a treatment quite challenging

Development of a 3D Ultrasound System to Investigate Post-Hemorrhagic Hydrocephalus in Pre-term Neonates

Clinical intracranial ultrasound (US) is performed as a standard of care on neonates at risk of intraventricular hemorrhaging (IVH) and is also used after a diagnosis to monitor for potential ventricular dilation. However, it is difficult to estimate the volume of ventricles with 2D US due to their irregular shape. We developed a 3D US system to be used as an adjunct to a clinical system to investigate volumetric changes in the ventricles of neonates with IVH. Our system has been found have an error of within 1% of actual distance measurements in all three directions and volume measurements of manually segmented volumes from phantoms were not statistically significantly different from the actual values (p\u3e0.3). Inter-observer volume measurements of the lateral ventricles in a patient with grade III IVH found no significant differences between measurements. There is the potential to use this system in IVH patients to monitor the progression of ventriculomegaly over time

Hes1 and Hes5 activities are required for the normal development of the hair cells in the mammalian inner ear.

The mammalian inner ear contains two sensory organs, the cochlea and vestibule. Their sensory neuroepithelia are characterized by a mosaic of hair cells and supporting cells. Cochlear hair cells differentiate in four rows: a single row of inner hair cells (IHCs) and three rows of outer hair cells (OHCs). Recent studies have shown that Math1, a mammalian homolog of Drosophila atonal is a positive regulator of hair cell differentiation. The basic helix-loop-helix (bHLH) genes Hes1 and Hes5 (mammalian hairy and Enhancer-of-split homologs) can influence cell fate determination by acting as negative regulators to inhibit the action of bHLH-positive regulators. We show by using reverse transcription-PCR analysis that Hes1, Hes5, and Math1 are expressed in the developing mouse cochleae. In situ hybridization revealed a widespread expression of Hes1 in the greater epithelial ridge (GER) and in lesser epithelial ridge (LER) regions. Hes5 is predominantly expressed in the LER, in supporting cells, and in a narrow band of cells within the GER. Examination of cochleae from Hes1(-/-) mice showed a significant increase in the number of IHCs, whereas cochleae from Hes5(-/-) mice showed a significant increase in the number of OHCs. In the vestibular system, targeted deletion of Hes1 and to a lesser extent Hes5 lead to formation of supernumerary hair cells in the saccule and utricle. The supernumerary hair cells in the mutant mice showed an upregulation of Math1. These data indicate that Hes1 and Hes5 participate together for the control of inner ear hair cell production, likely through the negative regulation of Math1

Preterm neonatal lateral ventricle volume from three-dimensional ultrasound is not strongly correlated to two-dimensional ultrasound measurements

The aim of this study is to compare longitudinal two-dimensional (2-D) and three-dimensional (3-D) ultrasound (US) estimates of ventricle size in preterm neonates with posthemorrhagic ventricular dilatation (PHVD) using quantitative measurements of the lateral ventricles. Cranial 2-D US and 3-D US images were acquired from neonatal patients with diagnosed PHVD within 10 min of each other one to two times per week and analyzed offline. Ventricle index, anterior horn width, third ventricle width, and thalamo-occipital distance were measured on the 2-D images and ventricle volume (VV) was measured from 3-D US images. Changes in the measurements between successive image sets were also recorded. No strong correlations were found between VV and 2-D US measurements (R-2 between 0.69 and 0.36). Additionally, weak correlations were found between changes in 2-D US measurements and 3-D US VV (R-2 between 0.13 and 0.02). A trend was found between increasing 2-D US measurements and 3-D US-based VV, but this was not the case when comparing changes between 3-D US VV and 2-D US measurements. If 3-D US-based VV provides a more accurate estimate of ventricle size than 2-D US measurements, moderate-weak correlations with 3-D US suggest that monitoring preterm patients with PHVD using 2-D US measurements alone might not accurately represent whether the ventricles are progressively dilating. A volumetric measure (3-D US or MRI) could be used instead to more accurately represent changes. (C) The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI

Meningeal solitary fibrous tumour in a child.

INTRODUCTION: Meningeal solitary fibrous tumour is a relatively recent pathological entity that has rarely been described in children. With radiological techniques, it cannot be distinguished from meningiomas, and the diagnosis has to be confirmed histologically. CASE REPORT: We discuss the possible histogenesis of this tumour and the need for recognizing this lesion as a separate entity. We report the case of a 12-year-old boy who developed a meningeal solitary fibrous tumour; the main clinical symptoms were progressive headaches for a long period and recent transient hemiparesis. CONCLUSION: This child presents an uneventful evolution without additional therapy 3.5 years after surgery