Ecchordosis physaliphora presenting as hypnic headache.

Ecchordosis physaliphora (EP) is a rare benign congenital hamartomatous lesion originating from remnants of the notochord. EP has never been associated with hypnic headache before. We report for the first time two cases of EP associated with an hypnic headache. The latter is a form of sleep-related nocturnal headache whose pathogenesis has not been fully elucidated. A 61-year-old woman and a 41-year-old man had been complaining of a dull headache that woke them up every night for many months. In both cases, an enlarged cystic lesion in the prepontine cistern, compatible with ecchordosis physaliphora, was found on brain MRI. A diagnosis of hypnic headache secondary to EP was made. Ecchordosis physaliphora presenting as hypnic headache had never been described before. The low prevalence of both conditions (EP and HH) and their presence in two cases might suggest a possible causal association between the two conditions.

Increased prefrontal volume in PD with levodopa-induced dyskinesias: a voxel-based morphometry study.

Levodopa-induced dyskinesias represent disabling complications from long-term therapy with dopaminergic drugs for treating Parkinson's disease (PD). Although several neuroimaging studies have reported altered striatofrontal function that contributes to the emergence of these motor complications, the neuroanatomical correlates of this disorder are still unknown. Optimized voxel-based morphometry (VBM) was applied to the MRI brain images of 36 PD patients with levodopa-induced dyskinesias, 36 PD patients without levodopa-induced dyskinesias, and 32 age- and sex-matched controls. The VBM analysis comparing dyskinetic and nondyskinetic groups provided evidence of increased gray matter volume of the bilateral inferior frontal gyrus in dyskinetic patients, a finding that was more evident in patients with early-onset PD. No significant differences were detected in the dyskinetic and nondyskinetic groups when compared with the controls. Our findings suggest that the presence of dyskinesias in patients with PD is characterized by an aberrant neural plasticity that could play a role in the pathophysiology of these motor complications.

Accuracy of magnetic resonance parkinsonism index for differentiation of progressive supranuclear palsy from probable or possible Parkinson disease.

BACKGROUND: Combined measurements on conventional magnetic resonance imaging (MRI), such as midbrain area/pons area or magnetic resonance parkinsonism index (MRPI) (pons area/midbrain area × middle cerebellar peduncle width/superior cerebellar peduncle width), have been proposed as powerful tools in the differential diagnosis between progressive supranuclear palsy (PSP) and Parkinson disease (PD). In this study, we evaluated the accuracy of MRPI, compared with midbrain/pons ratio, in distinguishing PSP from probable and possible PD. METHODS: Forty-two PSP patients, 170 probable PD patients, 132 possible PD patients, and 38 control subjects underwent MRI and, for each patient, midbrain/pons ratio and MRPI were calculated. RESULTS: Midbrain/pons ratio showed low accuracy in distinguishing PSP patients from those with probable PD (92.9% sensitivity; 85.3% specificity; 86.8% diagnostic accuracy) or those with possible PD (88.1% sensitivity, 88.3% specificity, and 88.2% diagnostic accuracy) and control subjects (97.6% sensitivity, 92.1% specificity, and 95% diagnostic accuracy). By contrast, MRPI showed higher accuracy to distinguish PSP from probable PD (100% sensitivity, 99.4% specificity, and 99.5% diagnostic accuracy), from possible PD (100% sensitivity, 99.2% specificity, and 99.4% diagnostic accuracy), and from control subjects (sensitivity, specificity, and diagnostic accuracy of 100%). CONCLUSIONS: Our study confirms that MRPI is a more accurate measure than midbrain/pons ratio for differentiation of patients with PSP from those with probable and possible PD.

An magnetic resonance imaging T2*-weighted sequence at short echo time to detect putaminal hypointensity in Parkinsonisms.

At 1.5 T, T2*-weighted gradient echo (GE) sequences are more sensitive in revealing mineral deposition in the basal ganglia than standard T2 weighted sequences. T2*-weighted GE sequences, however, may detect putaminal hypointensities either in patients affected by parkinsonian syndromes or in healthy subjects. The aim of this study was to identify the magnetic resonance imaging (MRI) T2*-weighted sequence which more specifically detected putaminal hypointensities differentiating atypical parkinsonian syndromes from Parkinson's disease (PD) and control subjects. In a sample of 38 healthy subjects, we performed three T2*-weighted GE sequences at increasing time echo (TE; TE = 15 millisecond, TE = 25 millisecond, and echoplanar at TE = 40 millisecond; T2* sequences study). The sequence not showing any putaminal abnormality in the healthy subjects was then used to assess putaminal signal intensity in 189 patients with PD, 20 patients with multiple system atrophy (MSA), 41 patients with progressive supranuclear palsy (PSP), and in 150 age and sex-matched control subjects. In the T2* sequences study, the T2*-weighted TE = 15 (T2*/15) did not show any putaminal abnormalities in the healthy subjects. This sequence detected putaminal hypointensities in a significantly higher proportion of patients with MSA (35%, P < 0.05) and PSP (24.4%, P < 0.05) than in patients with PD (5.3%), but in none of the controls. The sensitivity of putaminal hypointensity in T2*/15 sequence was 25.4% for PD, 43.9% for PSP, and 55% for MSA versus controls whereas the specificity was 93.2% for all groups. Despite the suboptimal sensitivity, the high specificity of the T2*/15 sequence performed on routine MRI suggests its usefulness in clinical practice for identifying putaminal hypointensities associated with parkinsonian disorders.

Neurofunctional correlates of personality traits in relapsing-remitting multiple sclerosis: an fMRI study.

Extraversion and Neuroticism are two fundamental dimensions of human personality that influence cognitive functioning in healthy subjects. Little is known about personality changes that may occur in patients with multiple sclerosis (MS) nor about, in particular, their neurofunctional basis. The aim of this study is to determine the impact of personality characteristics on brain activity in patients with MS. Eighteen patients with clinically definite relapsing-remitting MS without any evidence of psychiatric or cognitive disorders and thirteen healthy controls matched for age, gender and education were investigated using functional magnetic resonance imaging (fMRI) during the execution of an "n-back" task. No differences were detected on the behavioral tests between the two groups, although the MS patients had lower total IQ and showed a trend towards higher Extraversion and Neuroticism scores than did the controls. fMRI analyses demonstrated that Extraversion scores were positively associated with brain activity in the fronto-parietal network including the superior parietal lobule and dorsolateral prefrontal cortex in both groups during the high load condition of the n-back task. Given the overlapping neural systems found in the two groups, we suggest that the neural activity associated with specific personality dimension is a neurophysiological characteristic preserved in patients with MS at an early stage in the course of their disease.

MR imaging index for differentiation of progressive supranuclear palsy from Parkinson disease and the Parkinson variant of multiple system atrophy.

PURPOSE: To prospectively assess sensitivity and specificity of magnetic resonance (MR) imaging measurements of midbrain, pons, middle cerebellar peduncles (MCPs), and superior cerebellar peduncles (SCPs) for differentiating progressive supranuclear palsy (PSP) from Parkinson disease (PD) and Parkinson variant of multiple system atrophy (MSA-P), with established consensus criteria as reference standard. MATERIALS AND METHODS: All study participants provided informed consent; study was approved by the institutional review board. Pons area, midbrain area, MCP width, and SCP width were measured in 33 consecutive patients with PSP (16 possible, 17 probable), 108 consecutive patients with PD, 19 consecutive patients with MSA-P, and 50 healthy control participants on T1-weighted MR images. The pons area-midbrain area ratio (P/M) and MCP width-SCP width ratio (MCP/SCP) were also used, and an index termed MR parkinsonism index was calculated [(P/M).(MCP/SCP)]. Differences in MR imaging measurements among groups were evaluated with Kruskal-Wallis test, Mann-Whitney U test, and Bonferroni correction. RESULTS: Midbrain area and SCP width in patients with PSP (23 men, 10 women; mean age, 69.3 years) were significantly (P < .001) smaller than in patients with PD (62 men, 46 women; mean age, 65.8 years), patients with MSA-P (five men, 14 women; mean age, 64.0 years), and control participants (25 men, 25 women; mean age, 66.6 years). P/M and MCP/SCP were significantly larger in patients with PSP than in patients in other groups and control participants. All measurements showed some overlap of values between patients with PSP and patients from other groups and control participants. MR parkinsonism index value was significantly larger in patients with PSP (median, 19.42) than in patients with PD (median, 9.40; P < .001), patients with MSA-P (median, 6.53; P < .001), and control participants (median, 9.21; P < .001), without overlap of values among groups. No patient with PSP received a misdiagnosis when the index was used (sensitivity and specificity, 100%). CONCLUSION: The MR parkinsonism index can help distinguish patients with PSP from those with PD and MSA-P on an individual basis.

Apparent diffusion coefficient of the superior cerebellar peduncle differentiates progressive supranuclear palsy from Parkinson's disease.

The early diagnosis of progressive supranuclear palsy (PSP) may be challenging, because of clinical overlapping features with Parkinson's disease (PD) and other parkinsonian syndromes such as the Parkinsonian variant of multiple system atrophy (MSA-P). Conventional MRI can help in differentiating parkinsonian disorders but its diagnostic accuracy is still unsatisfactory. On the basis of the pathological demonstration of superior cerebellar peduncle (SCP) atrophy in patients with PSP, we assessed the SCP apparent diffusion coefficient (ADC) values in patients with PSP, PD, and MSA-P in order to evaluate its differential diagnostic value in vivo. Twenty-eight patients with PSP (14 with possible-PSP and 14 with probable-PSP), 15 PD, 15 MSA-P, and 16 healthy subjects were studied by using diffusion weighted imaging (DWI). ADC was calculated in regions of interest defined in the left and right SCP by two clinically blinded operators. Intrarater (r = 0.98, P < 0.001) and interrater reliability (r = 0.97; P < 0.001) for SCP measurements were high. Patients with PSP had higher SCP rADC values (median 0.98 x 10(-3)mm(2)/s) than patients with PD (median 0.79 x 10(-3) mm(2)/s, P < 0.001), MSA-P (median 0.79 x 10(-3) mm(2)/s, P < 0.001), and healthy controls (median 0.80 x 10(-3) mm(2)/s, P < 0.001). DWI discriminated patients with PSP from PD and healthy subjects on the basis of SCP rADC individual values (100% sensitivity and specificity) and from patients with MSA-P (96.4% sensitivity and 93.3% specificity). The higher values of rADC in SCP of patients with PSP correspond with the in vivo microstructural feature of atrophy detected postmortem and provide an additional support for early discrimination between PSP and other neurodegenerative parkinsonisms.

Impact of catechol-O-methyltransferase Val(108/158) Met genotype on hippocampal and prefrontal gray matter volume.

A variation in catechol-O-methyltransferase (COMT) gene (Val(108/158)Met) affects the physiological response of hippocampal-prefrontal circuits, predicts variation in human memory and is associated with increased risk for psychiatric disorders. Using optimized voxel-based morphometry we studied the effect of this functional polymorphism on the anatomy of the hippocampus, and the prefrontal cortex. Fifty-seven healthy participants were investigated (nine had Met/Met, 30 Val/Met, and 14 Val/Val). Voxel-based morphometry showed that individuals who are homozygous for the Val-COMT allele had greater gray matter volume of the prefrontal cortex bilaterally, whereas Met-COMT carriers were associated with increased tissue volume of the hippocampus bilaterally. This study provides evidence that the Val(108/158)Met polymorphism of the COMT gene might be responsible for individual variation in the human brain morphology.

MAO A VNTR polymorphism and variation in human morphology: a VBM study.

The X-linked monoamine oxidase A (MAO A) gene, coding for an enzyme especially involved in the serotonin catabolism, presents a well-characterized functional polymorphism (long and short variants) in the promoter region that alters the transcriptional activity of the gene and hence the function of the corresponding proteins. Using optimized voxel-based morphometry, we studied the effect of this functional polymorphism on brain morphology in normal individuals. Fifty-nine male healthy individuals (33 MAO A-high and 26 MAO A-low) were investigated. Voxel-based morphometry showed that the carriers of the long variant were significantly associated with loss of grey matter in orbitofrontal cortex, bilaterally. This study reveals pronounced genotype-related structural changes in a specific prefrontal region previously observed to mediate neurofunctional responses in behavioral tasks.

Ventro-lateral prefrontal activity during working memory is modulated by MAO A genetic variation.

Several lines of evidence have highlighted the role of the serotonergic system in working memory (WM) processes. The X-linked Mono-Amine Oxidase A (MAO A) gene, coding for an enzyme especially involved in the serotonin (5-HT) catabolism, presents a well-characterized functional polymorphism consisting in a variable number of tandem repeats (VNTR) in the promoter region with high activity and low activity variants. The high activity allele carriers have been associated with higher enzyme expression, lower amine concentration and altered prefrontal cortex (PFC) function during motor inhibition, but a direct effect of MAO A genotype on WM-related brain activity has not been demonstrated. We have studied the relationship of this polymorphism to brain activity elicited by a spatial working memory task (n-back) using blood oxygenation level-dependent functional magnetic resonance imaging in 30 healthy male individuals matched for a series of demographic and genetic variables (COMT Val108/158Met). We show that the high activity allele was significantly (p-level<0,001) associated with increased activity of the right ventro-lateral PFC (VLPFC, BA 47) during the high load condition of the n-back task. Our data reveal pronounced genotype-related functional changes in specific prefrontal region (VLPFC) subserving spatial working memory. Moreover, given the well-known role of this area in inhibitory control, our finding also provides new evidence for the involvement of 5-HT in PFC-mediated WM function.

A Cellular Neural Network methodology for the automated segmentation of multiple sclerosis lesions.

We present a new application based on genetic algorithms (GAs) that evolves a Cellular Neural Network (CNN) capable of automatically determining the lesion load in multiple sclerosis (MS) patients from magnetic resonance imaging (MRI). In particular, it seeks to identify brain areas affected by lesions, whose presence is revealed by areas of higher intensity if compared to healthy tissue. The performance of the CNN algorithm has been quantitatively evaluated by comparing the CNN output with the expert's manual delineation of MS lesions. The CNN algorithm was run on a data set of 11 MS patients; for each one a single dataset of MRI images (matrix resolution of 256×256 pixels) was acquired. Our automated approach gives satisfactory results showing that after the learning process the CNN is capable of detecting MS lesions with different shapes and intensities (mean DICE coefficient=0.64). The system could provide a useful support tool for the evaluation of lesions in MS patients, although it needs to be evolved and developed in the future.

Non-paraneoplastic limbic encephalitis characterized by mesio-temporal seizures and extratemporal lesions: a case report.

Limbic encephalitis (LE) can be either paraneoplastic or a non-paraneoplastic autoimmune disorder. Magnetic resonance imaging (MRI) of the brain on T2-weighted fluid-attenuated inversion recovery (FLAIR) classically shows hyperintensities of the temporal structures, but multifocal involvement of extratemporal cortex has also been described in paraneoplastic LE. Here we describe a 27-year-old woman whose idiopathic autoimmune (glutamic acid decarboxylase-antibody positive) LE debuted with multiple daily mesio-temporal seizures, amnesia and multifocal extratemporal cortical MRI abnormalities. Mesio-temporal MRI signal increase was found after 20 days. This case report highlights that early diagnosis of non-paraneoplastic LE may be considered in patients with multiple daily mesio-temporal seizures and amnesia even in the absence of early typical MRI abnormalities.