To identify early cognitive and neuroimaging features of sporadic nonfluent/agrammatic variant of primary progressive aphasia (nfvPPA) caused by frontotemporal lobar degeneration (FTLD) subtypes.
We prospectively collected clinical, neuroimaging, and neuropathologic data in 11 patients with sporadic nfvPPA with FTLD-tau (nfvPPA-tau, n = 9) or FTLD–transactive response DNA binding protein pathology of 43 kD type A (nfvPPA-TDP, n = 2). We analyzed patterns of cognitive and gray matter (GM) and white matter (WM) atrophy at presentation in the whole group and in each pathologic subtype separately. We also considered longitudinal clinical data.
At first evaluation, regardless of pathologic FTLD subtype, apraxia of speech (AOS) was the most common cognitive feature and atrophy involved the left posterior frontal lobe. Each pathologic subtype showed few distinctive features. At presentation, patients with nfvPPA-tau presented with mild to moderate AOS, mixed dysarthria with prominent hypokinetic features, clear agrammatism, and atrophy in the GM of the left posterior frontal regions and in left frontal WM. While speech and language deficits were prominent early, within 3 years of symptom onset, all patients with nfvPPA-tau developed significant extrapyramidal motor signs. At presentation, patients with nfvPPA-TDP had severe AOS, dysarthria with spastic features, mild agrammatism, and atrophy in left posterior frontal GM only. Selective mutism occurred early, when general neurologic examination only showed mild decrease in finger dexterity in the right hand.
Clinical features in sporadic nfvPPA caused by FTLD subtypes relate to neurodegeneration of GM and WM in frontal motor speech and language networks. We propose that early WM atrophy in nfvPPA is suggestive of FTLD-tau pathology while early selective GM loss might be indicative of FTLD-TDP.
Histopathological studies in Alzheimer's disease (AD) suggest severe and region-specific neurodegeneration of the basal forebrain cholinergic system (BFCS). Here, we studied the between-center reliability and diagnostic accuracy of MRI-based BFCS volumetry in a large multicenter data set, including participants with prodromal (n = 41) or clinically manifest AD (n = 134) and 148 cognitively healthy controls. Atrophy was determined using voxel-based and region-of-interest based analyses of high-dimensionally normalized MRI scans using a newly created map of the BFCS based on postmortem in cranio MRI and histology. The AD group showed significant volume reductions of all subregions of the BFCS, which were most pronounced in the posterior nucleus basalis Meynert (NbM). The mild cognitive impairment-AD group showed pronounced volume reductions in the posterior NbM, but preserved volumes of anterior-medial regions. Diagnostic accuracy of posterior NbM volume was superior to hippocampus volume in both groups, despite higher multicenter variability of the BFCS measurements. The data of our study suggest that BFCS morphometry may provide an emerging biomarker in AD.
Atrophy; biomarker; cholinergic system; dementia; European DTI Study on Dementia
No established therapeutic protocol has been proposed to date for childhood-onset neuromyelitis optica (NMO) spectrum disorders (NMOSDs). We report the response of 5 NMO immunoglobulin (Ig)G–positive pediatric cases to a standardized B-cell–targeted first-line immunosuppressive protocol with rituximab for prevention of relapses.
Retrospective observational cohort study.
All patients included in the study showed disease remission after rituximab induction. Relapses always occurred in conjunction with CD19+ B-cell repopulation and appeared less severe than prior to treatment. At the end of follow-up, neurologic disability and MRI findings stabilized or improved in all the patients, with only minor and transient side effects. Oral steroid discontinuation was possible in all the patients.
Our protocol is well-tolerated and has provided encouraging results in terms of control of relapses and progression of disability. An early intervention with rituximab might affect the disease course in pediatric NMO-IgG–positive NMOSDs.
Classification of evidence:
This study provides Class IV evidence that for children with NMOSDs, rituximab is well-tolerated and stabilizes or improves neurologic disability.
In multiple sclerosis (MS), accurate, in vivo characterization of dynamic inflammatory pathological changes occurring in newly forming lesions could have major implications for understanding disease pathogenesis and mechanisms of tissue destruction. Here, we investigated the potential of ultrahigh-field MRI (7T), particularly phase imaging combined with dynamic contrast enhancement, to provide new insights in acute MS lesions.
Sixteen active MS patients were studied at 7T. Noncontrast, high-resolution T2* magnitude and phase scans, T1 scans before/after gadolinium contrast injection, and dynamic contrast-enhanced (DCE) T1 scans were acquired. T2*/phase features and DCE pattern were determined for acute and chronic lesions. When possible, one-year follow-up 7T MRI was performed.
Of 49 contrast-enhancing lesions, 44 could be analyzed. Centrifugal DCE lesions appeared isointense or hypointense on phase images, whereas centripetal DCE lesions showed thin, hypointense phase rims that clearly colocalized with the initial site of contrast enhancement. This pattern generally disappeared once enhancement resolved. On the other hand, in 43 chronic lesions also selected for the presence of hypointense phase rims, the findings were stable over time, and the rims were typically thicker and darker. These considerations suggest different underlying pathological processes in the two lesion types.
Ultrahigh-field MRI and, especially, phase contrast, are highly sensitive to tissue changes in acute MS lesions, which differ from the patterns seen in chronic lesions. In acute lesions, the hypointense phase rim reflects the expanding inflammatory edge and may directly correspond to inflammatory byproducts and sequelae of blood-brain barrier opening.
inflammatory process; 7T phase imaging; multiple sclerosis
A 10-year-old girl presented with subacute lower limb weakness and gait ataxia. MRI revealed a large multicystic spinal cord lesion with patchy enhancement (figure 1, A–B) and 3 small (<6 mm) periventricular and deep white matter brain lesions. The presence of serum anti-aquaporin-4 immunoglobulin G (AQP4) (ELISA assay) and compatible neuropathologic features from neurosurgical specimens1 (figure 2) suggested the diagnosis of a neuromyelitis optica spectrum disorder.2 Targeted immunotherapy was started with partial lesion resolution (figure 1C).
To investigate grey (GM) and white matter (WM) abnormalities and their effects on cognitive and behavioral deficits in a large, phenotypically and genotypically well-characterized cohort of classic adult (aDM1, age at onset ≥20 years) or juvenile (jDM1, age at onset <20 years) patients with myotonic dystrophy type 1 (DM1).
A case-control study including 51 DM1 patients (17 jDM1 and 34 aDM1) and 34 controls was conducted at an academic medical center. Clinical, cognitive and structural MRI evaluations were obtained. Quantitative assessments of regional GM volumes, WM hyperintensities (WMHs), and microstructural WM tract damage were performed. The association between structural brain damage and clinical and cognitive findings was assessed.
DM1 patients showed a high prevalence of WMHs, severe regional GM atrophy including the key nodes of the sensorimotor and main cognitive brain networks, and WM microstructural damage of the interhemispheric, corticospinal, limbic and associative pathways. WM tract damage extends well beyond the focal WMHs. While aDM1 patients had severe patterns of GM atrophy and WM tract damage, in jDM1 patients WM abnormalities exceeded GM involvement. In DM1, WMHs and microstructural damage, but not GM atrophy, correlated with cognitive deficits.
WM damage, through a disconnection between GM structures, is likely to be the major contributor to cognitive impairment in DM1. Our MRI findings in aDM1 and jDM1 patients support the hypothesis of a degenerative (premature aging) origin of the GM abnormalities and of developmental changes as the principal substrates of microstructural WM alterations in DM1.
Using resting state (RS) functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI), we identified the predictors of clinical improvement following constraint-induced movement therapy (CIMT) in pediatric patients with chronic hemiplegia.From 14 children with congenital or acquired brain injury and 10 sex- and age-matched healthy controls, brain dual-echo, DTI and RS fMRI sequences were acquired before CIMT. The Quality of Upper Extremities Skills Test and the Gross Motor Function Measure (GMFM) were administered at baseline, at the end of CIMT (10 weeks), and after 6 months. Mean diffusivity and fractional anisotropy (FA) were measured in the lesion responsible for the clinical symptomatology, the affected and unaffected corticospinal tract (CST), motor transcallosal fibers, and uncinate fasciculus (as an internal control). Independent component analysis was used to identify the sensorimotor RS network. The ability of baseline MRI variables to predict clinical changes over time was assessed using multivariate linear models. At baseline, patients had increased mean diffusivity in the symptomatic lesion and decreased FA in the symptomatic lesion, affected corticospinal tract, and motor transcallosal fibers. A reduced RS functional connectivity was found in the bilateral cerebellum, left precentral gyrus, and right secondary sensorimotor cortex. At follow up, Quality of Upper Extremities Skills Test and GMFM scales improved significantly. Baseline average lesion FA predicted clinical improvement at week 10, and baseline functional connectivity of the right secondary sensorimotor cortex and cerebellum predicted GMFM improvement at month 6. DTI and RS fMRI offer promising and objective markers to predict clinical outcomes following CIMT in pediatric patients with congenital or acquired hemiplegia.
Electronic supplementary material
The online version of this article (doi:10.1007/s13311-013-0189-2) contains supplementary material, which is available to authorized users.
MRI; DTI; Tractography; Resting-state functional connectivity; Brain injury; Constraint-induced movement therapy
We first tested the brain reserve (BR) hypothesis in multiple sclerosis (MS) by examining whether larger maximal lifetime brain volume (MLBV; determined by genetics) protects against disease-related cognitive impairment, and then investigated whether cognitive reserve (CR) gained through life experience (intellectually enriching leisure activities) protects against cognitive decline independently of MLBV (BR).
Sixty-two patients with MS (41 relapsing-remitting MS, 21 secondary progressive MS) received MRIs to estimate BR (MLBV, estimated with intracranial volume [ICV]) and disease burden (T2 lesion load; atrophy of gray matter, white matter, thalamus, and hippocampus). Early-life cognitive leisure was measured as a source of CR. We assessed cognitive status with tasks of cognitive efficiency and memory. Hierarchical regressions were used to investigate whether higher BR (ICV) protects against cognitive impairment, and whether higher CR (leisure) independently protects against cognitive impairment over and above BR.
Cognitive status was positively associated with ICV (R2 = 0.066, p = 0.017). An ICV × disease burden interaction (R2 = 0.050, p = 0.030) revealed that larger ICV attenuated the impact of disease burden on cognition. Controlling for BR, higher education (R2 = 0.047, p = 0.030) and leisure (R2 = 0.090, p = 0.001) predicted better cognition. A leisure × disease burden interaction (R2 = 0.037, p = 0.030) showed that leisure independently attenuated the impact of disease burden on cognition. Follow-up analyses revealed that BR protected against cognitive inefficiency, not memory deficits, whereas CR was more protective against memory deficits than cognitive inefficiency.
We provide evidence of BR in MS, and show that CR independently protects against disease-related cognitive decline over and above BR. Lifestyle choices protect against cognitive impairment independently of genetic factors outside of one's control.
This is a cross-sectional study aimed at investigating cognitive performances in patients with primary lateral sclerosis (PLS) and using diffusion tensor (DT) magnetic resonance imaging (MRI) to determine the topographical distribution of microstructural white matter (WM) damage in patients with or without cognitive deficits.
DT MRI scans were obtained from 21 PLS patients and 35 age- and sex-matched healthy controls. All PLS patients underwent a comprehensive neuropsychological battery. Tract-based-spatial-statistics (TBSS) was used to perform a whole-brain voxel-wise analysis of fractional anisotropy (FA), axial, radial (radD) and mean diffusivity (MD).
Ten PLS patients had abnormal scores in at least one neuropsychological test (PLS with cognitive deficits, PLS-cd). Compared with healthy controls and cognitively unimpaired PLS patients (PLS-cu), PLS-cd cases showed decreased FA and increased MD and radD in the corticospinal tract (CST), corpus callosum, brainstem, anterior limb of internal capsule, superior and inferior longitudinal fasciculi, fornix, thalamic radiations, and parietal lobes, bilaterally. Compared with healthy controls, PLS-cd patients showed further decreased FA and increased radD in the cerebellar WM, bilaterally. Compared with controls, PLS-cu patients showed decreased FA in the mid-body of corpus callosum. In PLS, executive and language test scores correlated with WM damage.
This is the first study evaluating the relationship between cognitive performance and WM tract damage in PLS patients. PLS can be associated with a multi-domain cognitive impairment. WM damage to interhemispheric, limbic and major associative WM tracts seem to be the structural correlate of cognitive abnormalities in these patients.
Diffusion tensor imaging (DTI) based assessment of white matter fiber tract integrity can support the diagnosis of Alzheimer’s disease (AD). The use of DTI as a biomarker, however, depends on its applicability in a multicenter setting accounting for effects of different MRI scanners. We applied multivariate machine learning (ML) to a large multicenter sample from the recently created framework of the European DTI study on Dementia (EDSD). We hypothesized that ML approaches may amend effects of multicenter acquisition. We included a sample of 137 patients with clinically probable AD (MMSE 20.6±5.3) and 143 healthy elderly controls, scanned in nine different scanners. For diagnostic classification we used the DTI indices fractional anisotropy (FA) and mean diffusivity (MD) and, for comparison, gray matter and white matter density maps from anatomical MRI. Data were classified using a Support Vector Machine (SVM) and a Naïve Bayes (NB) classifier. We used two cross-validation approaches, (i) test and training samples randomly drawn from the entire data set (pooled cross-validation) and (ii) data from each scanner as test set, and the data from the remaining scanners as training set (scanner-specific cross-validation). In the pooled cross-validation, SVM achieved an accuracy of 80% for FA and 83% for MD. Accuracies for NB were significantly lower, ranging between 68% and 75%. Removing variance components arising from scanners using principal component analysis did not significantly change the classification results for both classifiers. For the scanner-specific cross-validation, the classification accuracy was reduced for both SVM and NB. After mean correction, classification accuracy reached a level comparable to the results obtained from the pooled cross-validation. Our findings support the notion that machine learning classification allows robust classification of DTI data sets arising from multiple scanners, even if a new data set comes from a scanner that was not part of the training sample.
The role of biomarkers in predicting pathological findings in the frontotemporal dementia (FTD) clinical spectrum disorders is still being explored. We present comprehensive, prospective longitudinal data for a 66 year old, right-handed female who met current criteria for the nonfluent/agrammatic variant of primary progressive aphasia (nfvPPA). She first presented with a 3-year history of progressive speech and language impairment mainly characterized by severe apraxia of speech. Neuropsychological and general motor functions remained relatively spared throughout the clinical course. Voxel-based morphometry (VBM) showed selective cortical atrophy of the left posterior inferior frontal gyrus (IFG) and underlying insula that worsened over time, extending along the left premotor strip. Five years after her first evaluation, she developed mild memory impairment and underwent PET-FDG and PiB scans that showed left frontal hypometabolism and cortical amyloidosis. Three years later (11 years from first symptom), post-mortem histopathological evaluation revealed Pick’s disease, with severe degeneration of left IFG, mid-insula, and precentral gyrus. Alzheimer’s disease (AD) (CERAD frequent / Braak Stage V) was also detected. This patient demonstrates that biomarkers indicating brain amyloidosis should not be considered conclusive evidence that AD pathology accounts for a typical FTD clinical/anatomical syndrome.
Nonfluent primary progressive aphasia; PPA; apraxia of speech; Voxel-based morphometry; PiB-PET; Pick’s disease; Alzheimer disease; Frontotemporal dementia
T-cell vaccination (TCV) for multiple sclerosis (MS) refers to treatment with autologous anti-myelin T-cells, attenuated by irradiation. Previously published clinical trials have been all open-labeled.
To evaluate the safety and efficacy of TCV in progressive MS, in a double-blind, controlled clinical trial.
Twenty-six patients with relapsing-progressive MS were enrolled in the study (mean age: 39±9.8 years; mean EDSS: 4.4±1.7). T-cell lines reactive to 9 different peptides of the myelin antigens, MBP, MOG and PLP were raised from the patients' peripheral blood. The patients were randomized into two groups: 19 were treated with TCV (four subcutaneous injections of 10–30×106 T-cells, attenuated by irradiation, on days 1, 30, 90 and 180) and 7 patients were treated with sham injections. Twenty-four patients (17 in the TCV group and 7 in the placebo) were eligible for per-protocol analysis.
At one year following the inclusion, an increase in the EDSS (+0.50) and an increase in 10-meter walking time (+0.18 sec), were observed in the placebo group; in the TCV group there was a decrease in the EDSS (−0.44; p<0.01) and in the 10-meter walking time (0.84 sec; p<0.005). Sixteen of the 17 patients (94.1%) in the TCV group remained relapse-free during the year of the study, as compared to 42.9% in the placebo group (p = 0.01 and p = 0.03 with adjustment). The proportion of patients with any relapse during the year of the study in the TCV-group, was reduced by 89.6%., as compared to the placebo-treated group. MRI parameters did not change significantly.
This is the first controlled, double-blind trial with TCV in progressive MS. The results demonstrate the feasibility and safety of the procedure, and provide significant indications of clinical efficacy. Further studies with larger groups of subjects are warranted.
Primary progressive aphasia is a clinical syndrome that encompasses three major phenotypes: non-fluent/agrammatic, semantic and logopenic. These clinical entities have been associated with characteristic patterns of focal grey matter atrophy in left posterior frontoinsular, anterior temporal and left temporoparietal regions, respectively. Recently, network-level dysfunction has been hypothesized but research to date has focused largely on studying grey matter damage. The aim of this study was to assess the integrity of white matter tracts in the different primary progressive aphasia subtypes. We used diffusion tensor imaging in 48 individuals: nine non-fluent, nine semantic, nine logopenic and 21 age-matched controls. Probabilistic tractography was used to identify bilateral inferior longitudinal (anterior, middle, posterior) and uncinate fasciculi (referred to as the ventral pathway); and the superior longitudinal fasciculus segmented into its frontosupramarginal, frontoangular, frontotemporal and temporoparietal components, (referred to as the dorsal pathway). We compared the tracts’ mean fractional anisotropy, axial, radial and mean diffusivities for each tract in the different diagnostic categories. The most prominent white matter changes were found in the dorsal pathways in non-fluent patients, in the two ventral pathways and the temporal components of the dorsal pathways in semantic variant, and in the temporoparietal component of the dorsal bundles in logopenic patients. Each of the primary progressive aphasia variants showed different patterns of diffusion tensor metrics alterations: non-fluent patients showed the greatest changes in fractional anisotropy and radial and mean diffusivities; semantic variant patients had severe changes in all metrics; and logopenic patients had the least white matter damage, mainly involving diffusivity, with fractional anisotropy altered only in the temporoparietal component of the dorsal pathway. This study demonstrates that both careful dissection of the main language tracts and consideration of all diffusion tensor metrics are necessary to characterize the white matter changes that occur in the variants of primary progressive aphasia. These results highlight the potential value of diffusion tensor imaging as a new tool in the multimodal diagnostic evaluation of primary progressive aphasia.
primary progressive aphasia; progressive non-fluent aphasia; semantic dementia; logopenic progressive aphasia; diffusion tensor imaging
Resting state (RS) functional MRI recently identified default network abnormalities related to cognitive impairment in MS. fMRI can also be used to map functional connectivity (FC) while the brain is at rest and not adhered to a specific task. Given the importance of the anterior cingulate cortex (ACC) for higher executive functioning in MS, we here used the ACC as seed-point to test for differences and similarities in RS-FC related to sustained attention between MS patients and controls.
Block-design rest phases of 3 Tesla fMRI data were analyzed to assess RS-FC in 31 patients (10 clinically isolated syndromes, 16 relapsing-remitting, 5 secondary progressive MS) and 31 age- and gender matched healthy controls (HC). Participants underwent extensive cognitive testing.
In both groups, signal changes in several brain areas demonstrated significant correlation with RS-activity in the ACC. These comprised the posterior cingulate cortex (PCC), insular cortices, the right caudate, right middle temporal gyrus, angular gyri, the right hippocampus, and the cerebellum. Compared to HC, patients showed increased FC between the ACC and the left angular gyrus, left PCC, and right postcentral gyrus. Better cognitive performance in the patients was associated with increased FC to the cerebellum, middle temporal gyrus, occipital pole, and the angular gyrus.
We provide evidence for adaptive changes in RS-FC in MS patients compared to HC in a sustained attention network. These results extend and partly mirror findings of task-related fMRI, suggesting FC may increase our understanding of cognitive dysfunction in MS.
The aim of this study was to explore the pattern of regional cortical thickness in patients with non-familial amyotrophic lateral sclerosis (ALS) and to investigate whether cortical thinning is associated with disease progression rate. Cortical thickness analysis was performed in 44 ALS patients and 26 healthy controls. Group differences in cortical thickness and the age-by-group effects were assessed using vertex-by-vertex and multivariate linear models. The discriminatory ability of MRI variables in distinguishing patients from controls was estimated using the Concordance Statistics (C-statistic) within logistic regression analyses. Correlations between cortical thickness measures and disease progression rate were tested using the Pearson coefficient. Relative to controls, ALS patients showed a bilateral cortical thinning of the primary motor, prefrontal and ventral frontal cortices, cingulate gyrus, insula, superior and inferior temporal and parietal regions, and medial and lateral occipital areas. There was a significant age-by-group effect in the sensorimotor cortices bilaterally, suggesting a stronger association between age and cortical thinning in ALS patients compared to controls. The mean cortical thickness of the sensorimotor cortices distinguished patients with ALS from controls (C-statistic ≥0.74). Cortical thinning of the left sensorimotor cortices was related to a faster clinical progression (r = −0.33, p = 0.03). Cortical thickness measurements allowed the detection and quantification of motor and extramotor involvement in patients with ALS. Cortical thinning of the precentral gyrus might offer a marker of upper motor neuron involvement and disease progression.
Interferon-beta (IFNB) therapy for multiple sclerosis can lead to the induction of neutralizing antibodies (NAbs) against IFNB. Various methods are used for detection and quantification of NAbs.
Blood samples from 125 IFNB-1b–treated patients, which were tested NAb negative or NAb positive after conclusion of a clinical study, were retested three years after first being assessed in four different laboratories that offer routine NAb testing to practicing neurologists. The myxovirus protein A (MxA) induction assay, the cytopathic effect (CPE) assay (two laboratories), or the luciferase assay were used. Intra- and inter-laboratory agreement between assays with respect to NAb detection and NAb titer quantification were evaluated.
High agreement for NAb detection (kappa coefficient, 0.86) and for titer levels was observed for the intra-laboratory comparison in the laboratory using the MxA induction assay performed three years ago and now. A similarly high agreement for NAb detection (kappa coefficient, 0.87) and for titer quantification was noted for the MxA assay of this laboratory with one of two laboratories using the CPE assay. All other inter-laboratory comparisons showed kappa values between 0.57 and 0.68 and remarkable differences in individual titer levels.
There are considerable differences in the detection and quantification of IFNB-induced NAbs among laboratories offering NAb testing for clinical practice using different assay methods. It is important that these differences are considered when interpreting NAb results for clinical decision-making and when developing general recommendations for potentially clinically meaningful NAb titer levels.
Multiple sclerosis; Clinical trials randomized controlled; IFNB-1b; Interferon beta; Neutralizing antibodies; Round robin
A new semi-automatic method for segmenting the spinal cord from MR images is presented. The method is based on an active surface (AS) model of the cord surface, with intrinsic smoothness constraints. The model is initialized by the user marking the approximate cord center-line on a few representative slices, and the compact surface parametrization results in a rapid segmentation, taking on the order of one minute. Using 3-D acquired T1-weighted images of the cervical spine from human controls and patients with multiple sclerosis, the intra- and inter-observer reproducibilities were evaluated, and compared favorably with an existing cord segmentation method. While the AS method overestimated the cord area by approximately 14% compared to manual outlining, correlations between cord cross-sectional area and clinical disability scores confirmed the relevance of the new method in measuring cord atrophy in multiple sclerosis. Segmentation of the cord from 2-D multi-slice T2-weighted images is also demonstrated over the cervical and thoracic region. Since the cord center-line is an intrinsic parameter extracted as part of the segmentation process, the image can be resampled such that the center-line forms one coordinate axis of a new image, allowing simple visualization of the cord structure and pathology; this could find wider application in standard radiological practice.
BACKGROUND AND PURPOSE
To test whether the ~20% of multiple sclerosis (MS) patients exhibiting a clinically benign disease course also suffer minimal neural dysfunction as reflected by the global concentration of their MR marker - N-acetyl-aspartate (NAA).
MATERIALS AND METHODS
Global brain NAA amounts, QNAA, were obtained with non-localizing whole-head proton MR spectroscopy in 43 benign relapsing-remitting (RR) MS patients (30 female, 13 male) 44.7±7.3 years old (mean ± standard deviation) of 21.0±4.4 (range: 15 – 35) years of disease duration from first symptom and Expanded Disability Status Scale (EDSS) score of 1.9 (range: 0–3). QNAA was by divided by the brain volume (from MRI segmentation) to normalize into whole-brain NAA (WBNAA) concentration. All participants gave IRB approved written informed consent and the study was HIPAA compliant.
The patients' lesion load was 12.2±7.7 cm3. Their 8.3±1.8 mM WBNAA was 35% lower than controls (p<0.001). Individual average loss rates (absolute loss compared with control divided by disease duration) clustered around 0.22±0.09 mM/year (1.7%/year assuming monotonic decline). This rate could be extrapolated from that already reported for RR MS patients of much shorter disease duration. WBNAA did not correlate with lesion load or EDSS.
Normal WBNAA is not characteristic of benign MS, and is not an early predictor of its course. These patients, therefore, probably benefit from successful compensation and sparing of eloquent regions. Since they may ultimately suffer a rapid decline once their brain plasticity is exhausted, they may benefit from treatment options offered to more affected patients.
We assessed abnormalities within the principal brain resting state networks (RSNs) in patients with Leber's hereditary optic neuropathy (LHON) to define whether functional abnormalities in this disease are limited to the visual system or, conversely, tend to be more diffuse. We also defined the structural substrates of fMRI changes using a connectivity-based analysis of diffusion tensor (DT) MRI data. Neuro-ophthalmologic assessment, DT MRI and RS fMRI data were acquired from 13 LHON patients and 13 healthy controls. RS fMRI data were analyzed using independent component analysis and SPM5. A DT MRI connectivity-based parcellation analysis was performed using the primary visual and auditory cortices, bilaterally, as seed regions. Compared to controls, LHON patients had a significant increase of RS fluctuations in the primary visual and auditory cortices, bilaterally. They also showed decreased RS fluctuations in the right lateral occipital cortex and right temporal occipital fusiform cortex. Abnormalities of RS fluctuations were correlated significantly with retinal damage and disease duration. The DT MRI connectivity-based parcellation identified a higher number of clusters in the right auditory cortex in LHON vs. controls. Differences of cluster-centroid profiles were found between the two groups for all the four seeds analyzed. For three of these areas, a correspondence was found between abnormalities of functional and structural connectivities. These results suggest that functional and structural abnormalities extend beyond the visual network in LHON patients. Such abnormalities also involve the auditory network, thus corroborating the notion of a cross-modal plasticity between these sensory modalities in patients with severe visual deficits.
Cognitive deficits in semantic dementia have been attributed to anterior temporal lobe grey matter damage; however, key aspects of the syndrome could be due to altered anatomical connectivity between language pathways involving the temporal lobe. The aim of this study was to investigate the left language-related cerebral pathways in semantic dementia using diffusion tensor imaging-based tractography and to combine the findings with cortical anatomical and functional magnetic resonance imaging data obtained during a reading activation task. The left inferior longitudinal fasciculus, arcuate fasciculus and fronto-parietal superior longitudinal fasciculus were tracked in five semantic dementia patients and eight healthy controls. The left uncinate fasciculus and the genu and splenium of the corpus callosum were also obtained for comparison with previous studies. From each tract, mean diffusivity, fractional anisotropy, as well as parallel and transverse diffusivities were obtained. Diffusion tensor imaging results were related to grey and white matter atrophy volume assessed by voxel-based morphometry and functional magnetic resonance imaging activations during a reading task. Semantic dementia patients had significantly higher mean diffusivity, parallel and transverse in the inferior longitudinal fasciculus. The arcuate and uncinate fasciculi demonstrated significantly higher mean diffusivity, parallel and transverse and significantly lower fractional anisotropy. The fronto-parietal superior longitudinal fasciculus was relatively spared, with a significant difference observed for transverse diffusivity and fractional anisotropy, only. In the corpus callosum, the genu showed lower fractional anisotropy compared with controls, while no difference was found in the splenium. The left parietal cortex did not show significant volume changes on voxel-based morphometry and demonstrated normal functional magnetic resonance imaging activation in response to reading items that stress sublexical phonological processing. This study shows that semantic dementia is associated with anatomical damage to the major superior and inferior temporal white matter connections of the left hemisphere likely involved in semantic and lexical processes, with relative sparing of the fronto-parietal superior longitudinal fasciculus. Fronto-parietal regions connected by this tract were activated normally in the same patients during sublexical reading. These findings contribute to our understanding of the anatomical changes that occur in semantic dementia, and may further help to explain the dissociation between marked single-word and object knowledge deficits, but sparing of phonology and fluency in semantic dementia.
semantic dementia; semantic knowledge; diffusion tensor-based tractography; functional MRI; voxel-based morphometry
Whereas focal and diffuse brain damage on conventional MRI is seen in patients with neuropsychiatric systemic lupus erythematosus (NSLE), the spinal cord seems to be rarely involved. Diffusion tensor (DT) MRI provides information on the patterns of tissue disruption of the central nervous system, which may go undetected by conventional MRI.
To quantify the extent of otherwise “occult” injury of the cervical cord in NSLE, and to improve our understanding of its nature.
Subjects and methods
Conventional and DT MRI scans of the cervical cord and brain were acquired from 11 patients with NSLE and 10 healthy controls. Histograms of mean diffusivity (MD) and fractional anisotropy (FA) of the cervical cord and brain were analysed. Measures of cervical cord and brain atrophy and focal lesion loads were computed.
Only one patient had a single focal lesion of the cord whereas all had multiple brain lesions on conventional MRI scans. Cord and brain volumes did not differ between patients and controls. Mean peak height of the cervical cord MD histogram (p = 0.0001) and average brain FA (p = 0.001) were significantly lower in patients than in controls. Average cord MD was correlated with average brain MD (r = 0.69, p = 0.01) and FA (r = −0.81, p = 0.002).
DT MRI shows mild and otherwise “occult” cord damage in NSLE, which might be secondary to Wallerian degeneration of long tract fibres passing trough damaged areas of the brain.
Empathy and affective appraisals for conspecifics are among the hallmarks of social interaction. Using functional MRI, we hypothesized that vegetarians and vegans, who made their feeding choice for ethical reasons, might show brain responses to conditions of suffering involving humans or animals different from omnivores. We recruited 20 omnivore subjects, 19 vegetarians, and 21 vegans. The groups were matched for sex and age. Brain activation was investigated using fMRI and an event-related design during observation of negative affective pictures of human beings and animals (showing mutilations, murdered people, human/animal threat, tortures, wounds, etc.). Participants saw negative-valence scenes related to humans and animals, alternating with natural landscapes. During human negative valence scenes, compared with omnivores, vegetarians and vegans had an increased recruitment of the anterior cingulate cortex (ACC) and inferior frontal gyrus (IFG). More critically, during animal negative valence scenes, they had decreased amygdala activation and increased activation of the lingual gyri, the left cuneus, the posterior cingulate cortex and several areas mainly located in the frontal lobes, including the ACC, the IFG and the middle frontal gyrus. Nonetheless, also substantial differences between vegetarians and vegans have been found responding to negative scenes. Vegetarians showed a selective recruitment of the right inferior parietal lobule during human negative scenes, and a prevailing activation of the ACC during animal negative scenes. Conversely, during animal negative scenes an increased activation of the inferior prefrontal cortex was observed in vegans. These results suggest that empathy toward non conspecifics has different neural representation among individuals with different feeding habits, perhaps reflecting different motivational factors and beliefs.
We used tensor-based morphometry (TBM) to: 1) map gray matter (GM) volume changes associated with motor learning in young healthy individuals; 2) evaluate if GM changes persist three months after cessation of motor training; and 3) assess whether the use of different schemes of motor training during the learning phase could lead to volume modifications of specific GM structures. From 31 healthy subjects, motor functional assessment and brain 3D T1-weighted sequence were obtained: before motor training (time 0), at the end of training (two weeks) (time 2), and three months later (time 3). Fifteen subjects (group A) were trained with goal-directed motor sequences, and 16 (group B) with non purposeful motor actions of the right hand. At time 1 vs. time 0, the whole sample of subjects had GM volume increase in regions of the temporo-occipital lobes, inferior parietal lobule (IPL) and middle frontal gyrus, while at time 2 vs. time 1, an increased GM volume in the middle temporal gyrus was seen. At time 1 vs. time 0, compared to group B, group A had a GM volume increase of the hippocampi, while the opposite comparison showed greater GM volume increase in the IPL and insula in group B vs. group A. Motor learning results in structural GM changes of different brain areas which are part of specific neuronal networks and tend to persist after training is stopped. The scheme applied during the learning phase influences the pattern of such structural changes.
Background: Mycophenolate mofetil (MMF) is an oral DNA base synthesis inhibitor with immunomodulatory effects on B cells, T cells, and macrophages.
Objective: To conduct a safety and tolerability pilot study of interferon beta-1a (IFN-b1a) in combination with either placebo or oral MMF in multiple sclerosis (MS).
Methods: Twenty-four treatment-naïve R–RMS patients participated in a one-year prospective, placebo-controlled, blinded, safety pilot clinical trial. Every patient injected weekly intramuscular interferon beta-1a. The cohort was then randomized (1 : 1) to either active oral MMF or identical-appearing placebo tablets. Clinical evaluations were assessed every 3 months, along with brain MRI scans performed at baseline and repeated every 60 days for one year. Comprehensive laboratory assessments were monitored for safety, along with adverse events.
Results: In this small pilot investigation, no differences were identified between the two treatment groups with respect to patient-reported adverse events, MRI metrics, or laboratory abnormalities. Notwithstanding these observations, and the limited number of patients treated, trends appeared to favor the combination therapy regimen.
Conclusions: The combination treatment regimen of interferon beta-1a and MMF appeared to be well tolerated in this pilot study. Despite the small sample size, therapeutic trends were observed in favor of combination therapy. An adequately powered controlled trial of MMF in MS appears warranted.
CellCept; immunosuppression; mycophenolate mofetil; relapsing-remitting multiple sclerosis; treatment naïve
Many promising MRI approaches for research or clinical management of multiple sclerosis (MS) have recently emerged, or are under development or refinement. Advanced MRI methods need to be assessed to determine whether they allow earlier diagnosis or better identification of phenotypes. Improved post-processing should allow more efficient and complete extraction of information from images. Magnetic resonance spectroscopy should improve in sensitivity and specificity with higher field strengths and should enable the detection of a wider array of metabolites. Diffusion imaging is moving closer to the goal of defining structural connectivity and, thereby, determining the functional significance of lesions at specific locations. Cell-specific imaging now seems feasible with new magnetic resonance contrast agents. The imaging of myelin water fraction brings the hope of providing a specific measure of myelin content. Ultra-high-field MRI increases sensitivity, but also presents new technical challenges. Here, we review these recent developments in MRI for MS, and also look forward to refinements in spinal-cord imaging, optic-nerve imaging, perfusion MRI, and functional MRI. Advances in MRI should improve our ability to diagnose, monitor, and understand the pathophysiology of MS.