Central olfactory processing in patients with disorders of consciousness.

BACKGROUND AND PURPOSE: Previous studies have demonstrated that individuals suffering from disorder of consciousness (DOC) maintain some minor neural processing of percepts mediated by senses that early in their pathway intersect the thalamus, a key dysfunctional area in DOC patients. Here the degree of sensory preservation within the olfactory system, a system that lacks an obligatory thalamic relay, and its relationship to the consciousness level in DOC patients of various etiologies was assessed. METHODS: Clinical Coma Recovery Scale - Revised (CRS-R) as well as cerebral responses to odors by means of functional magnetic resonance were obtained in a group of vegetative state/unresponsive wakefulness syndrome (n = 26) patients, minimally conscious state (n = 7) patients and healthy controls (n = 25). RESULTS: A majority of vegetative state/unresponsive wakefulness syndrome patients (58%) and 100% of minimally conscious state patients demonstrated a significant preservation of olfactory neural processing, manifested by activation within the piriform cortex, an area considered as a primary olfactory region. Degree of preservation of olfactory processing differed linearly in line with the patients' etiologies where groups demonstrating greater conscious awareness demonstrated more significant processing. Viewed over all DOC patients, there was a significant negative association between odor-related activity in the orbitofrontal cortex and CRS-R scores. CONCLUSIONS: It is demonstrated that DOC patients exhibit a significant preservation of olfactory neural processing with a clear relationship to etiopathologies and clinical measures even years after of chronification of DOC.

Myxoid glioneuronal tumor: Histopathologic, neuroradiologic, and molecular features in a single center series.

BACKGROUND: Myxoid glioneuronal tumor (MGT) is a benign glioneuronal neoplasm recently introduced in the World Health Organization (WHO) classification of the central nervous system (CNS) tumors. MGTs are typically located in the septum pellucidum, foramen of Monro or periventricular white matter of the lateral ventricle. They were previously diagnosed as dysembryoplastic neuroepithelial tumors (DNT), showing histological features almost indistinguishable from classical cortical DNT. Despite that, MGTs have been associated with a specific dinucleotide substitution at codon 385 in the platelet-derived growth factor receptor alpha (PDGFRA) gene, replacing a lysine residue with either leucine or isoleucine (p. LysK385Leu/Iso). This genetic variation has never been described in any other CNS tumor. MATERIALS AND METHODS: Thirty-one consecutive tumors, previously diagnosed as DNTs at the Meyer Children's Hospital IRCCS between January 2010 and June 2021 were collected for a comprehensive study of their clinical, imaging, pathological features, and molecular profile. RESULTS: In six out of the thirty-one tumors we had previously diagnosed as DNTs, we identified the recurrent dinucleotide mutation in the PDGFRA. All six tumors were typically located within the periventricular white matter of the lateral ventricle and in the septum pellucidum. We then renamed these lesions as MGT, according to the latest WHO CNS classification. In all patients we observed an indolent clinical course, without recurrence. CONCLUSION: MGT represent a rare but distinct group of neoplasm with a typical molecular profiling, a characteristic localization, and a relative indolent clinical course.

Significance of multiple neurophysiological measures in patients with chronic disorders of consciousness.

OBJECTIVE: The aim of this study was to verify the value of multiple neurophysiological tests in classifying disorders of consciousness (DOCs) in patients in a chronic vegetative or minimal consciousness state categorised on the basis of the Coma Recovery Scale (CRS). METHODS: The study included 142 patients, all of whom underwent long (18h) EEG-polygraphic recordings including one night. The EEG was scored using the Synek scale and sleep patterns using an arbitrary scale. Absolute total power and relative EEG power were evaluated in different frequency bands. Multimodal evoked potentials (EPs), including auditory event-related potentials, were also evaluated and scored. RESULTS: The most information came from the combined multimodal EPs and sleep EEG scores. A two-step cluster analysis based on the collected information allowed a satisfactory evaluation of DOC severity. Spectral EEG properties seemed to be significantly related to DOC classes and CRS scores, but did not seem to make any significant additional contribution to DOC classification. CONCLUSIONS: Multiple electrophysiological evaluations based on EEG, sleep polygraphic recordings and multimodal EPs are helpful in assessing DOC severity and residual functioning in patients with chronic DOCs. SIGNIFICANCE: Simple electrophysiological measures that can be easily applied at patients' bedsides can significantly contribute to the recognition of DOC severity in chronic patients surviving a severe brain injury.

A number of schizencephaly patients including 2 brothers are heterozygous for germline mutations in the homeobox gene EMX2.

We report here that some patients affected by schizencephaly are heterozygous for mutations in EMX2, a homeobox gene implicated in the patterning of the developing forebrain. Schizencephaly is a very rare human congenital disorder characterized by a full-thickness cleft within the cerebral hemispheres. Large portions of these may be absent and replaced by cerebrospinal fluid. We previously reported the presence of EMX2 mutations in 7 out of 8 sporadic cases of schizencephaly. We now extend this analysis to 10 additional patients, including 2 brothers. Six patients were found to be heterozygous for de novo mutations in EMX2. In particular, the 2 brothers show the same mutation affecting the splicing of the first intron, while this mutation is absent in their parents and in the 2 unaffected siblings.

Familial schizencephaly associated with EMX2 mutation.

We describe two brothers aged 8 and 10 affected by severe bilateral schizencephaly, carrying an identical point mutation of the homeobox gene EMX2. Both children had severe neurologic deficits and mental retardation, although they differed in the anatomic extent of the brain malformation and in the severity of the clinical picture. The present findings, together with the reported cases of schizencephaly associated with EMX2 mutations, support the hypothesis that, at least in some cases, schizencephalies are determined by deleterious mutations of this homeobox gene. The different morphoclinical pictures suggest that, besides the EMX2 mutation, other factors are relevant in determining the severity of the brain malformation and clinical picture.

Sensitivities and predictive values of paraclinical tests for diagnosing multiple sclerosis.

The sensitivities and predictive values of visual, somatosensory, and brain auditory evoked potentials (EPs), cerebrospinal fluid oligoclonal banding (CSF-OB) and magnetic resonance imaging (MRI) were evaluated for the early diagnosis of clinically definite multiple sclerosis (CDMS). Paraclinical evidence of asymptomatic lesions allows a diagnosis of CDMS. Eighty-two patients in whom MS was suspected but diagnosis of CDMS was not possible entered the study prospectively. Paraclinical examinations were performed at entry. Patients were examined and underwent EPs every 6 months, and MRI yearly. After a mean follow-up of 2.9 years, 28 patients (34%) had developed CDMS (McDonald-Halliday criteria). The initial MRI was strongly suggestive of MS in 19 of these (68%), while 27 (96%) had at least one MS-like abnormality in the initial MRI. CSF-OB and EPs had lower sensitivities. CDMS developed during follow-up in 19 of the 36 patients (53%) who had an initial MRI strongly suggestive of MS but in only 1 of the 25 who had normal MRI when first studied. These results support previous conclusions that MRI is the most sensitive test for detecting white matter asymptomatic lesions, and the most predictive for the diagnosis of CDMS.

Hallervorden-Spatz disease: MR and pathologic findings.

PURPOSE: To compare the MR findings of eight cases with clinical diagnosis of Hallervorden-Spatz disease (HSD) with the pathologic findings of two other cases of HSD. MATERIALS AND METHODS: The eight imaged cases were studied with 0.5-T (seven cases) and/or 1.5-T (five cases) units. Six patients also had CT scans. The two other cases with proven HSD had detailed histologic evaluation. RESULTS: The 1.5-T findings showed abnormalities confined to the pallidum, which presented a diffuse low signal intensity in T2-weighted images, and an anteromedial area of high signal intensity (eye-of-the-tiger sign). In 0.5-T studies, low signal intensity was less evident and poorly detectable in spin echo, but gradient-echo images could enhance its demonstration; the area of high signal intensity was always well demonstrated. In three cases (three with 1.5 T, one with 0.5 T) a central spot of low signal intensity was seen in this area. The pathologic cases, in addition to neuroaxonal swellings and iron deposits, exhibited areas of "loose" tissue with vacuolization and lesser amounts of iron in the anteromedial part of the pallidum, in a location corresponding to the area of high signal intensity of the imaged cases. CONCLUSION: Comparison of MR findings with the pathologic studies demonstrates that the low signal intensity in T2-weighted images at 1.5 T corresponds to iron deposits in a dense tissue, and that the high signal intensity of the eye-of-the-tiger sign corresponds to an area of loose tissue with vacuolization. No correlation was found in the two pathologic cases for the central spot of low signal intensity.

A case of 3-methylglutaconic aciduria misdiagnosed as cerebral palsy.

3-Methylglutaconic aciduria is a rare hereditary metabolic disorder characterized by increased urinary excretion of 3-methylglutaconic and 3-methylglutaric acids. Four clinical forms are recognized. This study presents the case of a 5-year-old male with type IV 3-methylglutaconic aciduria, initially diagnosed as "static encephalopathy." The slow evolution and other clinical characteristics, together with cerebral magnetic resonance imaging (MRI) findings, eventually directed the diagnosis to organic aciduria that was confirmed by urine test. This study proposes that the clinical criteria for childhood cerebral palsy should be rigorously respected; neuroimaging studies, particularly MRI, should be conducted to confirm the diagnosis, especially in atypical cases.

Neurogenic arthrogryposis multiplex congenita: clinical and MRI findings.

A clinical and magnetic resonance imaging (MRI) study on a selected group of 11 children, with a diagnosis of neurogenic arthrogryposis multiplex congenita (AMC) based on clinical, electromyographic, and muscle biopsy findings, is presented to determine the extent of central nervous system involvement in AMC. Family history, pregnancy, perinatal problems, other abnormalities, and epileptic seizures were reviewed. Neurologic examination, electroencephalography, intellectual assessment, and MRI study both of spinal cord and brain were performed. The clinical and laboratory findings disclosed evidence of spinal cord lesions with involvement of anterior horn cell function in all patients, and impairment of cerebral function in 5 patients. MRI revealed spinal cord atrophy in 3 patients, diffuse atrophy in 2 patients, and involved thoraco-lumbar segments in 1 patient. Cranial MRI studies demonstrated features of developmental brain abnormalities in 3 patients, cortical frontal atrophy in 2, and was normal in 4. In neurogenic AMC patients, MRI examination of the spinal cord and brain may help to clarify the pathogenesis of the disease and is helpful for prognostic and therapeutic purposes.

Effect of bilateral subthalamic electrical stimulation in Parkinson's disease.

BACKGROUND: Bilateral high frequency subthalamic stimulation has been reported to be effective in the treatment of Parkinson's disease and levodopa-induced dyskinesias. To analyze the results of this surgical procedure we critically reviewed 17 parkinsonian patients with advanced disease complicated by motor fluctuations and dyskinesias. METHODS: Between January 1998 and June 1999 these 17 consecutive patients (age 48-68 years; illness duration 8-27 years) underwent bilateral stereotactically guided implantation of electrodes into the subthalamic nucleus in the Department of Neurosurgery of the Istituto Nazionale Neurologico "C. Besta." Parameters used for continuous high-frequency stimulation were: frequency 160 Hz, pulse width 90 microsec, mean amplitude 2.05 +/- 0.45 V. Parts II and III of the UPDRS were used to assess motor performance before and after operation by the neurologic team. The follow-up ranged between 6 and 18 months. RESULTS: At latest examination, mean UPDRS II and III scores had improved by 30% (on stimulation, off therapy) with mean 50% reduction in daily off time. Peak dyskinesias and early morning dystonias also improved in relation to therapy reduction. Side effects were persistent postoperative supranuclear oculomotor palsy and postural instability in one case, worsened off-medication hypophonia in three, and temporary nocturnal confusion episodes in three. Postoperative MRI revealed a clinically silent intracerebral haematoma in one case. One electrode required repositioning. CONCLUSIONS: Continuous high frequency STN stimulation is an effective treatment for advanced PD. A functionally useful and safe electrode placement can be performed without microrecording.

Costello syndrome: a cancer predisposing syndrome?

Costello Syndrome is a specific MCA/MR syndrome mainly characterized by dysmorphic facial features, peculiar biphasic growth pattern, motor and mental retardation, ectodermal anomalies involving skin and nails, and age dependent development of nasal and perianal papillomata. Heart malformations and/or hypertrophic cardiomyopathy are frequently observed. We report a 4-year-old girl with Costello syndrome who developed an intrathoracic ganglioneuroblastoma. In previous reports two patients with ectodermal tumours have been described, a ganglioneuroblastoma of the adrenal gland and an epithelioma. This third report suggests that neural crest neoplasia may be a significant risk factor for children with Costello syndrome.

Pendular nystagmus in hypomyelinating leukodystrophy.

We report the case of a 49-year old woman affected by hypomyelinating leukodystrophy. She presented with typical pendular nystagmus that was analyzed with video-oculography which is provided in the supplementary material of the report. The pendular nystagmus was accompanied by upper limb ataxia on the index-to-nose test. The video was partly recorded with a slow-motion technique in order to better demonstrate the ataxia and the pendular nystagmus. The brain MRI demonstrated a characteristic pattern of hypomyelination. Pendular nystagmus is a key clinical sign that contributes to the diagnosis of CNS hypomyelination when a leukodystrophic pattern is observed on brain MRI.

Preoperative language lateralization in temporal lobe epilepsy (TLE) predicts peri-ictal, pre- and post-operative language performance: An fMRI study.

In patients with temporal lobe epilepsy (TLE), assessment of language lateralization is important as anterior temporal lobectomy may lead to language impairments. Despite the widespread use of fMRI, evidence of its usefulness in predicting postsurgical language performance is scant. We investigated whether preoperative functional lateralization is related to the preoperative language performance, peri-ictal aphasia, and can predict language outcome one year post-surgery. We studied a total of 72 TLE patients (42 left, 30 right), by using three fMRI tasks: Naming, Verb Generation and Fluency. Functional lateralization indices were analyzed with neuropsychological scores and presence of peri-ictal aphasia. The key findings are:1)Both left and right TLE patients show decreased left lateralization compared to controls.2)Lateralization correlates with language performance before surgery. In left TLE, decreased left lateralization correlates with better fluency performance. In right TLE, increased left lateralization during the Naming task correlates with better naming.3)Left lateralization correlates with peri-ictal aphasia in left TLE patients.4)Lateralization correlates with language performance after surgery. In a subgroup of left TLE who underwent surgery (17 left), decreased left lateralization is predictive of better naming performance at 6 and 12 months after surgery. The present study highlights the clinical relevance of fMRI language lateralization in TLE, especially to predict language outcome one year post-surgery. We also underline the importance of using fMRI tasks eliciting frontal and anterior temporal activations, when studying left and right TLE patients.

CT and MRI of brain tumors.

Imaging plays a crucial role in the management of patients with brain tumors. The technical improvement of computed tomography (CT) and magnetic resonance (MRI) with the development of, new imaging techniques strongly improved the detection and characterization of brain tumors. For the optimal therapeutic management of the oncologic patient not only the recognition of the lesion is needed, but also the exclusion of other diseases that can mimic brain tumors. The preoperative assessment of malignancy and of relationships of the tumor with surrounding eloquent structures are also necessary to allow the correct choice of therapy and to warn surgeons of possible risks of the surgical approach. This article is an overview of the current state of neuroimaging of the most frequent brain tumors including CT and MRI, perfusion weighted imaging (PWI), diffusion weighted imaging (DWI), diffusion tensor imaging (DTI), proton magnetic resonance spectroscopy (1H-MRS) and functional MRI based on blood oxygen level (fMRI BOLD). Indeed, in the last years, a transition took place from a purely anatomy-based radiology to one that incorporates functional, hemodynamic, metabolic, cellular, and cytoarchitectural alterations. Neuroimaging has evolved into a comprehensive diagnostic tool that allows the characterization of morphologic as well as biologic alterations to diagnose and grade brain tumors and to monitor and assess treatment response and patient prognosis.

Combined 7-T MRI and histopathologic study of normal and dysplastic samples from patients with TLE.

OBJECTIVES: The purpose of the study was to investigate the abnormalities of cortical lamination observed in temporal lobe specimens obtained during surgery for intractable temporal lobe epilepsy (TLE) with hippocampal sclerosis. Specifically, we aimed to 1) correlate high-field ex vivo MRI with histopathologic analysis and 2) evaluate the effect of tissue fixation on image contrast. METHODS: A cohort of 13 specimens was considered. T2-weighted imaging and relaxometry were performed during and after fixation using a 7-T experimental scanner. After imaging, the specimens were studied with histopathologic (Black Gold myelin fiber staining) and immunohistochemical (NeuN neuronal staining) methods in order to explore the correspondence between MRI and histopathologic features. RESULTS: The principal findings of this study are that 1) superior MRI contrast is obtained among the cortical layers using completely fixed specimens as opposed to recently excised tissue, 2) the intensity of the T2-weighted MRI signal is lowest (hypointensity) at the site of highest fiber concentration and cellular density, and highest (hyperintensity) when the density of fibers and cells is lowest, and 3) the MRI signal is altered in presence of abnormal cortical lamination (focal cortical dysplasia type IA). CONCLUSIONS: High resolution ex vivo MRI enables the study of intracortical organization in normal and pathologic areas. Comparisons between MRI, NeuN, and Black Gold indicate that the differences apparent in T2-weighted images are mainly related to fiber concentration, although neuronal density might also play a role.

Bio-image warehouse system: concept and implementation of a diagnosis-based data warehouse for advanced imaging modalities in neuroradiology.

Advanced neuroimaging techniques, such as functional magnetic resonance imaging (fMRI), chemical shift spectroscopy imaging (CSI), diffusion tensor imaging (DTI), and perfusion-weighted imaging (PWI) create novel challenges in terms of data storage and management: huge amounts of raw data are generated, the results of analysis may depend on the software and settings that have been used, and most often intermediate files are inherently not compliant with the current DICOM (digital imaging and communication in medicine) standard, as they contain multidimensional complex and tensor arrays and various other types of data structures. A software architecture, referred to as Bio-Image Warehouse System (BIWS), which can be used alongside a radiology information system/picture archiving and communication system (RIS/PACS) system to store neuroimaging data for research purposes, is presented. The system architecture is conceived with the purpose of enabling to query by diagnosis according to a predefined two-layered classification taxonomy. The operational impact of the system and the time needed to get acquainted with the web-based interface and with the taxonomy are found to be limited. The development of modules enabling automated creation of statistical templates is proposed.

MRI in neuronal ceroid lipofuscinosis.

Magnetic resonance imaging in neuronal ceroid lipofuscinosis (NCL) demonstrates cerebral and cerebellar atrophy, T2-hyperintensity of the lobar white matter and thinning of the cerebral cortex. The association of these findings, although non specific, can be observed in all the different forms of NCL, narrows the differential diagnosis of the infantile progressive encephalopathies and may suggest the diagnosis.