Temporal differences and commonalities between hand and tool neural processing.

Object recognition is a complex cognitive process that relies on how the brain organizes object-related information. While spatial principles have been extensively studied, less studied temporal dynamics may also offer valuable insights into this process, particularly when neural processing overlaps for different categories, as it is the case of the categories of hands and tools. Here we focus on the differences and/or similarities between the time-courses of hand and tool processing under electroencephalography (EEG). Using multivariate pattern analysis, we compared, for different time points, classification accuracy for images of hands or tools when compared to images of animals. We show that for particular time intervals (~ 136-156 ms and ~ 252-328 ms), classification accuracy for hands and for tools differs. Furthermore, we show that classifiers trained to differentiate between tools and animals generalize their learning to classification of hand stimuli between ~ 260-320 ms and ~ 376-500 ms after stimulus onset. Classifiers trained to distinguish between hands and animals, on the other hand, were able to extend their learning to the classification of tools at ~ 150 ms. These findings suggest variations in semantic features and domain-specific differences between the two categories, with later-stage similarities potentially related to shared action processing for hands and tools.

[Cerebral venous thrombosis revealing neurosyphilis]. / Une thrombose veineuse cérébrale révélant une neurosyphilis.

INTRODUCTION: Syphilis is a bacterial infection which is increasing in France. Neurosyphilis is a rare manifestation of syphilis, mainly involving the meninges and the blood vessels. It is a rare cause of cerebral vascular stroke. Venous thrombosis of syphilitic origin is rarely described. OBSERVATION: We reported a case of a fifty-year-old patient hospitalized for bilateral non-painful decreased visual acuity with headache. The CT scan showed cerebral venous thrombosis from the right lateral sinus to the jugular gulf. Patient presented a bilateral papillar oedema on the ocular fundus. Lumbar puncture showed lymphocytic meningitis with blood and CSF serology suggestive of neurosyphilis. The patient received antibiotic therapy with penicillin G for 14days with curative anticoagulation for six months. The evolution was favorable. CONCLUSION: Cerebral venous thrombosis in neurosyphilis is a poorly described entity. This case report confirms the status of great simulator of syphilis. In the context of its worldwide recrudescence, syphilis must be evoked in front of an unexplained neurological disorder.

[Acid sphingomyelinase deficiency (Niemann-Pick disease type B) in adulthood: A retrospective multicentric study of 28 adult cases]. / Déficit en sphingomyélinase acide (maladie de Niemann-Pick B) : une étude rétrospective multicentrique de 28 patients adultes.

INTRODUCTION: Acid sphingomyelinase deficiency (ASMD) is an autosomal recessive disease with a clinical spectrum ranging from a neurovisceral infantile form (Niemann-Pick disease type A) to a chronic visceral form also encountered in adults (Niemann-Pick disease type B, NP-B). METHODS: Retrospective multicentric analysis of French adult patients with ASMD over the period 1985-March 2015. Clinical, biological, and imaging data were analyzed. RESULTS: Twenty-eight patients (19 males, 9 females) were analyzed. Diagnosis was made before the age of 10 years in 16 cases. Main symptoms at diagnosis were spleen/liver enlargement and interstitial lung disease. Biological abnormalities included: thrombocytopenia (platelet count <150 000/mm3) in 24 cases including 4 patients with platelet count <60 000/mm3, constantly low high-density lipoprotein (HDL) cholesterol, polyclonal hypergammaglobulinemia (n=6), monoclonal gammopathy of unknown significance (n=5), normal prothrombin level discordant with low factor V (n=5), elevated chitotriosidase level (n=11). The diagnosis was confirmed in all cases by deficient acid sphingomyelinase enzyme activity. SMPD1 gene sequencing was performed in 25 cases. The frequent p.R610del mutation was largely predominant, constituting 62% of the non-related alleles. During the follow-up period, three patients died before 50 years of age from cirrhosis, heart failure and lung insufficiency, respectively. CONCLUSION: ASMD in adulthood (NP-B) associates spleen/liver enlargement and interstitial lung disease. Early diagnosis and appropriate management are essential for reducing the risk of complications, improving quality of life, and avoiding inappropriate procedures such as splenectomy. To date, only symptomatic therapy is available. A phase 2/3 therapeutic trial with IV infusion of recombinant enzyme is on-going.

From face processing to face recognition: Comparing three different processing levels.

Verifying that a face is from a target person (e.g. finding someone in the crowd) is a critical ability of the human face processing system. Yet how fast this can be performed is unknown. The 'entry-level shift due to expertise' hypothesis suggests that - since humans are face experts - processing faces should be as fast - or even faster - at the individual than at superordinate levels. In contrast, the 'superordinate advantage' hypothesis suggests that faces are processed from coarse to fine, so that the opposite pattern should be observed. To clarify this debate, three different face processing levels were compared: (1) a superordinate face categorization level (i.e. detecting human faces among animal faces), (2) a face familiarity level (i.e. recognizing famous faces among unfamiliar ones) and (3) verifying that a face is from a target person, our condition of interest. The minimal speed at which faces can be categorized (∼260ms) or recognized as familiar (∼360ms) has largely been documented in previous studies, and thus provides boundaries to compare our condition of interest to. Twenty-seven participants were included. The recent Speed and Accuracy Boosting procedure paradigm (SAB) was used since it constrains participants to use their fastest strategy. Stimuli were presented either upright or inverted. Results revealed that verifying that a face is from a target person (minimal RT at ∼260ms) was remarkably fast but longer than the face categorization level (∼240ms) and was more sensitive to face inversion. In contrast, it was much faster than recognizing a face as familiar (∼380ms), a level severely affected by face inversion. Face recognition corresponding to finding a specific person in a crowd thus appears achievable in only a quarter of a second. In favor of the 'superordinate advantage' hypothesis or coarse-to-fine account of the face visual hierarchy, these results suggest a graded engagement of the face processing system across processing levels as reflected by the face inversion effects. Furthermore, they underline how verifying that a face is from a target person and detecting a face as familiar - both often referred to as "Face Recognition" - in fact differs.

New CT system architectures for high temporal resolution with applications to improved geometric dose efficiency and cardiac imaging.

PURPOSE: A new scalable computed tomography (CT) system architecture is introduced with the potential to achieve much higher temporal resolution than is possible with current CT designs while maintaining the flux per imaged slice near today's levels. The concept relies only on known technologies; in particular, effective rotation speeds several times higher than what is possible today can be achieved leveraging today's x-ray tube designs and capabilities. METHODS: The new CT architecture comprises the following elements: (1) decoupling of the source rotation from the detector rotation through the provision of two independent, coaxial and coplanar rotating gantries (drums), (2) observation of a source at a range of azimuthal angles with respect to a given detector cell, (3) utilization of a multiplicity of x-ray sources, (4) use of a wide-angle isocentered detector mounted on the independent detector drum, (5) the detector drum presents a wide angular aperture allowing x-rays from the various sources to pass through, with the active detector cells occupying about 240° in one configuration, and the wide aperture the complementary 120°, (6) antiscatter grids with absorbing lamellas oriented substantially parallel to the main gantry plane, and (7) optional sparse view acquisition in "bunches," a sparse sampling pattern potentially enabling further data-acquisition speedup for specific applications. Temporal resolution gains are achieved when K multiple sources are simultaneously in view of the extended detector. Accordingly, projection data relate to the sum of up to K line-integral terms; recovery of the individual line-integral estimates that form the input to the usual image reconstruction methods necessitates the inversion of a sparse linear system. When data for a tomographic slice are acquired during a full effective gantry rotation, the linear system is amenable to inversion; when high temporal resolution is sought, the system is underdetermined and a-priori information is useful in regularizing the problem. A regularization method is proposed whereby each sampling time interval is subdivided and individual projection data are acquired for each source during a subinterval. Other approaches involve spectral multiplexing. Thus, the use of an energy-discriminating detector such as a photon-counting detector will be advantageous to the proposed design. Recently developed volume-based scatter correction methods have the potential to apply to the proposed architectures. RESULTS: Mathematical modeling indicates acquisition of complete data for a given transaxial slice could be achieved in 50 ms or less, while delivering an x-ray exposure commensurate with that delivered by a system acquiring complete data in 200 ms. Applications include cardiac CT and the design of a CT system with nearly 100% geometric dose efficiency, whereby the effective rotation speed enables the use of a relatively narrow z-aperture detector, with no antiscatter grids. This represents a 33% dose reduction versus a system with 75% geometric dose efficiency. CONCLUSIONS: A new, scalable CT system architecture has been described that can potentially lead to large increases in temporal resolution. Potential applications include cardiac CT and the design of a system with 100% dose geometric dose efficiency. Future investigations will address the feasibility of the proposed approach.

[Cerebrotendinous xanthomatosis: a multicentric retrospective study of 15 adults, clinical and paraclinical typical and atypical aspects]. / Étude rétrospective multicentrique de 15 cas adultes de xanthomatose cérébrotendineuse : aspects cliniques et paracliniques typiques et atypiques.

INTRODUCTION: Cerebrotendinous xanthomatosis, a metabolic leukodystrophy with an autosomal recessive inheritance, is secondary to deficiency of sterol 27-hydroxylase, an enzyme involved in cholesterol catabolism. Classical symptoms include clinical or infraclinical xanthomas affecting the skin and tendons, early cataracts, neurological signs and diarrhea. Brain imaging reveals involvement of the dentate nuclei and periventricular white matter hyperintensities. The diagnosis is based on an increased cholestanol level in serum, confirmed by the presence of a mutation in the CYP27A1 gene. Treatment is based on chenodeoxycholic acid. METHOD: We report a retrospective multicentric study of 15 cases of cerebrotendinous xanthomatosis diagnosed in French adults. Clinical, molecular and MRI findings were recorded in all patients. RESULTS: The average age at diagnosis was 39years (range 27-65). Disease onset occurred in childhood in 73% of patients and in adulthood in 27%. All patients with a pediatric onset were diagnosed during adulthood (age range 28-65years). Clinical symptoms variably associated cerebellar syndrome, pyramidal syndrome, cognitive decline, epilepsy, neuropathy (sought in 10 of our patients, present in forms in 8), psychiatric disorders, cataract and xanthomas. One patient had an atypical presentation: monoparesis associated with xanthomas. Brain MRI was abnormal in all: findings consisted in T2-weighted hyperintensity of the dentate nuclei (47%), periventricular leuoencephalopathy (73%) which preferentially involved the posterior cerebral part (60%), leucoencephalopathy with a vascular pattern (7%), hyperintensity of the cortico-spinal tracts (53%), globi pallidi, corpus callosum and cerebral atrophy (33%). Serum cholestanol was elevated in 93% of patients. The most frequent mutation was 1183C>T (n=5/15). Under treatment with chenodeoxycholic acid, eight patients improved initially, followed by stabilization in five of them, and worsening in the others. Four patients died. CONCLUSION: Patients with the xanthoma-neurological disorder association should be tested for cerebrotendinous xanthomatosis. The disease often begins in childhood with a diagnostic delay but also in adulthood. Involvement of the dentate nuclei is specific but not sensitive and the supratentorial leucoencephalopathy is not specific but with an antero-posterior gradient. A vascular distribution and involvement of the corpus callosum are possible. Serum cholestanol assay is very reliable: an elevated level provides the diagnosis, which must nevertheless be confirmed by molecular biology.

[Vertex aplasia cutis congenita with bone defect: Management synthesis and review of the literature]. / Aplasia cutis congenita du vertex avec atteinte osseuse : synthèse sur la prise en charge et revue de la littérature.

Aplasia cutis congenita (ACC) of the vertex is a rare and potentially severe malformation. We report the case of a newborn boy presenting ACC of the vertex with a skull defect. Surgical closure of the skin was performed 5 days following birth, which allowed skin healing. The skull spontaneously remodelled perfectly 6 months later. When associated with skull defect, this rare malformation characterized by the absence of skin carries the risk of severe complications such as rupture of the superior sagittal sinus or infections. Based on a review of the literature, we purpose an overview of the medical and surgical management of vertex ACC, which depends on the size of the skin defect and the presence of a skull defect.

Acute bilateral mydriasis associated with anti-GQ1b antibody.

Miller Fisher syndrome (MFS) is an autoimmune neuropathy characterized by external ophthalmoplegia, ataxia and areflexia. Mydriasis is present in 35% of typical MFS. We report five patients with acute bilateral mydriasis, either isolated or associated with external ophthalmoplegia for which the presumed diagnosis of "atypical MFS" was confirmed by the positivity of anti-GQ1b antibodies. Acute bilateral mydriasis raises important differential diagnoses in clinical practice. This report demonstrates that acute mydriasis can be autoimmune mediated and that anti-GQ1b antibodies are useful to confirm the diagnosis in unexplained cases.

[Efficacy of replacement enzyme therapy on central nervous system manifestations in Fabry's disease]. / Efficacité de l'enzymothérapie substitutive sur le système nerveux central dans la maladie de Fabry.

INTRODUCTION: Fabry's disease (FD) an X-linked inherited lysosomal sphingolipidosis leads to a multisystemic disease. The efficacy of replacement enzyme therapy on the central nervous system manifestations has not been evaluated. OBSERVATION: A 38-year-old patient suffered from a Fabry's disease diagnosed at the age of 10. Since the age of 26, he suffered from repeated ischemic strokes. Since the age of 34, he was treated by enzyme replacement therapy (agalsidase beta, 1 mg/kg/14 days). He had a cerebral MRI evaluation 1 year and 4 years after the initiation of the enzyme therapy. No new clinical event occurred during the follow-up and the imaging did not evidence new lesion. DISCUSSION: We report the cerebral MRI follow-up under enzyme replacement therapy in a patient with Fabry's disease with central nervous system involvement. No new lesion appeared. CONCLUSION: Enzyme replacement therapy seems beneficial in Fabry's disease with central nervous system involvement.

[Chondrosarcomas of skull base treatment]. / Traitement des chondrosarcomes de la base du crâne.

BACKGROUND AND PURPOSE: Skull base chondrosarcomas are rare. Gross total removal is the treatment of choice, but can be difficult depending on the closeness of noble structures. Proton beam therapy can be associated in most cases. METHODS: Retrospective study of five cases treated in 13 years and study of the literature. RESULTS: Median age of patients was 34 years [28-46]. Cranial nerve palsy was the common clinical presentation. Tumor location was variable but always off midline. Treatment was surgical in all patients with a maximal resection and proton beam therapy associated for two cases. Surgical complications were rare with cranial nerve palsy as the main side effect. Outcomes were good with a median follow-up of 12.4 years [4.3-16.2]. DISCUSSION: The review of the literature showed that chondrosarcomas of skull base are rare. The best outcome is achieved with total surgical resection. Medical imaging can only give clues to the diagnosis. Pathology is required to obtain a precise immunohistochemistry diagnosis. Multidisciplinary treatment using proton beam therapy and surgical removal enables a good local control (90-100%) at 5 years with good quality-of-life. It is difficult to determine how many cases have been published (around 220 cases in the literature) since many surgical or radiotherapy series included the same patients.

[Sonography versus electrodiagnosis for the diagnosis of carpal tunnel syndrome in routine practice]. / Comparaison de l'échographie et de l'électroneurographie pour le diagnostic du syndrome du canal carpien en pratique courante.

INTRODUCTION: Many studies had been performed in the last years to prove the usefulness of ultrasonographic measurements of the median nerve in the diagnosis of carpal tunnel syndrome (CTS). We wanted to determine its reliability and to compare this technology with electromyography (EMG) in ordinary diagnostic conditions. METHODS: The study involved 90 wrists with suspected CTS, 35 controlateral wrists and 52 control wrists. The diagnosis of CTS was confirmed in 81 cases by the hand symptom diagram and the Tinnel and Phalen sign. The EMG examination evaluated medianulnar sensory latency difference to the ring finger and wrist-to-palm sensory conduction velocity. For the ultrasound diagnosis, the cross sectional area of the median nerve at the level of the pisiform bone, was considered. The sensitivity and specificity of the two techniques was calculated. RESULTS: Sensitive electroneurographic parameters showed a sensibility and specificity respectively of 79 and 80%. The cut-off point for ultrasound sensibility and specificity using ROC analysis was 11mm(2) for mean cross-sectional area. Sensitivity and specificity found in this way were 72% and 56%. Reliability was good with intra- and inter-reader intraclass correlation coefficients of 0.99, and interobserver coefficient of 0.88. Sonography found seven CTS among the 17 clinical CTS with normal electrophysiological findings. A statistically correlation was found between the cross-sectional section and the sensitive electrophysiologic parameters (r=0.43, p<0.001). CONCLUSIONS: In our study, ultrasonographic diagnostic value are not as good as electrophysiological value, like found in recent literature, probably because of the composition of our group of patients which is including many causes of acroparesthesias. This can mean that in clinical practice, sonography is a complementary tool instead, for example in cases of equivocal EMG.

[Anterior lumbar interbody fusion for treatment of failed back surgery syndrome: a retrospective study of 46 cases]. / Arthrodèses lombaires par voie antérieure dans le traitement des lombalgies et lomboradiculalgies récidivantes postchirurgicales : étude rétrospective de 46 cas.

BACKGROUND AND PURPOSE: Anterior lumbar interbody fusion (ALIF) has gained popularity for the treatment of degenerative disease of the lumbar spine. In this report, we present our experience with the ALIF procedure for treatment of failed back surgery syndrome following lumbar discectomy in a noncontrolled retrospective cohort. METHODS: From 1st January to 31 December 2005, we performed an ALIF in 46 patients presenting with low back pain with or without radiculopathy. All patients had a history of intractable pain resistant to conventional medical treatment and failed posterior lumbar surgery. Clinical and radiological outcomes were recorded. Neurological pain and functional outcomes were measured postoperatively (at 1, 3 and 12 months). Operative data, intraoperative complications, and the fusion rate were recorded. RESULTS: Forty-six patients with a preoperative diagnosis of failed back surgery syndrome underwent ALIF. The mean follow-up was 21 months. Back pain and leg pain completely disappeared in 60.9% of patients, decreased but required occasional medication in 28.3%, and 10.8% declared no benefit from ALIF surgery. CONCLUSION: On the basis of our results, we found ALIF to be a safe and effective procedure for the treatment of failed back surgery syndrome.

Chondrosarcoma of the skull base in Maffucci's syndrome.

We report a new case of skull base chondrosarcoma in Maffucci's syndrome. Maffucci's syndrome combining enchondromatosis with cutaneous haemangioma is rarely associated with chondrosarcoma. The review of literature highlights a small number of this pathological association.

[Transmaxillary approach to the skull base: surgical anatomy and guidelines]. / Voie d'abord transmaxillaire de la base du crâne : anatomie chirurgicale et repères.

BACKGROUND: A surgical and anatomic approach to the skull base using the transmaxillary route is presented. This route is well-known and used for a long time for sinus conditions. METHOD: This study was performed on injected cadavers. This study describes step by step this approach in microsurgical conditions following a vital lead: the infraorbital nerve. RESULTS: Anatomical landmarks are located in order to avoid complications. These complications are on one hand, hemorrhages by vascular lesions and on the other, definitive nerve palsy. CONCLUSION: Several skull base approaches exist, transfacial routes produce cosmetic damages. This route preserves the functional anatomy of the nose because it preserves the integrity of the lateral wall of the nasal cavity.

Causes of death amongst French patients with amyotrophic lateral sclerosis: a prospective study.

BACKGROUND AND PURPOSE: To prospectively investigate causes of death and the circumstances surrounding death in 302 patients with amyotrophic lateral sclerosis (ALS). The functional status of patients immediately before death was also determined. METHODS: Information was obtained from neurologists at ALS centres, patients' files, and, when deaths occurred outside a medical facility, attending physicians. RESULTS: Most patients (63%) died in a medical facility. The most frequently reported cause of death was respiratory failure (77%), including terminal respiratory insufficiency (58%), pneumonia (14%), asphyxia due to a foreign body (3%) and pulmonary embolism (2%). Ten per cent of patients died from other causes: post-surgical or traumatic conditions (5%), cardiac causes (3.4%), suicide (1.3%) and sudden death of unknown origin (0.7%). The cause of death could not be determined in 13% of cases (6% inside a medical facility and 25% outside). At the time of death, only 55% of patients were receiving riluzole, 33% were undergoing non-invasive ventilation, 3% had a tracheotomy and 37% a gastrostomy. CONCLUSION: The information provided by this study helps to improve our understanding of the natural history of the disease and may help optimize the quality of care we can offer patients at the end of life.