Pierluigi Lanza

Essential Head Tremor Is Associated with Cerebellar Vermis Atrophy: A Volumetric and Voxel-Based Morphometry MR Imaging Study

BACKGROUND AND PURPOSE: Our aim was to investigate the presence of brain gray matter (GM) abnormalities in patients with different forms of essential tremor (ET). MATERIALS AND METHODS: We used optimized voxel-based morphometry (VBM) and manually traced single region-of-interest analysis in 50 patients with familial ET and in 32 healthy subjects. Thirty patients with ET had tremor of the arms (a-ET), whereas the remaining 20 patients had both arm and head tremor (h-ET). RESULTS: VBM showed marked atrophy of the cerebellar vermis in the patients with h-ET with respect to healthy subjects (Pcorrected < .001). Patients with a-ET showed a trend toward a vermal GM volume loss that did not reach a significant difference with respect to healthy controls (Puncorrected < .01). The region-of-interest analysis showed a reduction of the cerebellar volume (CV) in the h-ET group (98.2 ± 13.6 mm3) compared with healthy controls (110.5 ± 15.5 mm3, P < .012) as well as in the entire vermal area (790.3 ± 94.5 mm2, 898.6 ± 170.6 mm2, P < .04 in h-ET and control groups, respectively). CONCLUSIONS: Atrophy of the cerebellar vermis detected in patients with h-ET strongly supports the evidence for the involvement of the cerebellum in the pathophysiology of ET. The lack of a significant CV loss observed in patients with a-ET suggests that a-ET and h-ET might represent distinct subtypes of the same disease.

Diffusion tensor MRI changes in cerebellar structures of patients with familial essential tremor

Objective: The aim of our study was to investigate the microstructural integrity of brain regions functionally involved in the tremor loop in patients with familial essential tremor (FET), using diffusion tensor imaging (DTI). Methods: Twenty-five patients with FET, 15 patients with Parkinson disease (PD), and 15 healthy subjects were studied. DTI was performed to measure fractional anisotropy (FA) and mean diffusivity (MD) in various regions of interest: red nucleus, dentate nucleus (DN), cerebellar white matter, middle (MCP) and superior cerebellar peduncle (SCP), and ventrolateral thalamus. Results: In patients with FET, FA values in the DN (median 0.19, range 0.13–0.23) were reduced (p < 0.001) compared with patients with PD (median 0.37, range 0.32–0.58) and healthy controls (median 0.36, range 0.33–0.40). In patients with FET, FA was also reduced (p = 0.003) and MD values increased (p < 0.001) in the SCP compared with patients with PD and healthy controls. Among patients with FET, those with longer disease duration showed FA values in the DN lower than those with shorter disease duration (p = 0.018). Patients with FET could be completely distinguished from both patient with PD and healthy controls using FA values of the DN alone. Conclusion: Neuroimaging evidence of microstructural changes consistent with neurodegeneration was found in the dentate nucleus (DN) and SCP of patients with familial essential tremor. This suggests that neurodegenerative pathology of cerebellar structures may play a role in essential tremor. Further studies are needed to assess the role of fractional anisotropy and mean diffusivity changes in DN and SCP in the differential diagnosis of essential tremor and Parkinson disease, which may present similar clinical signs at the onset of disease.

Cerebellar Atrophy in Essential Tremor Using an Automated Segmentation Method

BACKGROUND AND PURPOSE: Essential tremor (ET) is a slowly progressive disorder characterized by postural and kinetic tremors most commonly affecting the forearms and hands. Several lines of evidence from physiologic and neuroimaging studies point toward a major role of the cerebellum in this disease. Recently, voxel-based morphometry (VBM) has been proposed to quantify cerebellar atrophy in ET. However, VBM was not originally designed to study subcortical structures, and the complicated anatomy of the cerebellum may hamper the automatic processing of VBM. The aim of this study was to determine the efficacy and utility of using automated subcortical segmentation to identify atrophy of the cerebellum and other subcortical structures in patients with ET. MATERIALS AND METHODS: We used a recently developed automated volumetric method (FreeSurfer) to quantify subcortical atrophy in ET by comparing results obtained with this method with those provided by previous evidence. The study included T1-weighted MR images of 46 patients with ET grouped into those having arm ET (n = 27, a-ET) or head ET (n = 19, h-ET) and 28 healthy controls. RESULTS: Results revealed the expected reduction of cerebellar volume in patients with h-ET with respect to healthy controls after controlling for intracranial volume. No significant difference was detected in any other subcortical area. CONCLUSIONS: Volumetric data obtained with automated segmentation of subcortical and cerebellar structures approximate data from a previous study based on VBM. The current findings extend the literature by providing initial validation for using fully automated segmentation to derive cerebellar volumetric information from patients with ET.

MRI evidence of mesial temporal sclerosis in sporadic "benign" temporal lobe epilepsy.

Objective: To determine whether there is MRI-detectable mesial temporal sclerosis (MTS) in patients with sporadic benign temporal lobe epilepsy (BTLE). Methods: Brain MRIs were obtained from 101 consecutive, unrelated patients (51 women; mean age 37.3 ± 17.5 years; range 10 to 83 years) with BTLE, who reported rarely or never having had seizures at the time of long-term (>2 years) follow-up. The mean age at seizure onset was 22.3 ± 17.4 years; the mean duration of epilepsy was 16.4 ± 14.1 years. MRI diagnosis of MTS was based on the occurrence of hippocampal formation atrophy on T1 slices, an increased mesial temporal signal intensity alteration on fluid-attenuated inversion-recovery (FLAIR) or T2 images, or both. Results: Thirty-nine of 101 patients (38.6%) had MRI evidence of unilateral MTS (19/39 left MTS, 20/39 right MTS), which correlated with the epileptiform activity. Hyperintense FLAIR and T2 signal with or without atrophy was observed in 24 of 39 individuals. There was no difference between patients with or without MRI-detected MTS in age at onset and duration of epilepsy. Family history of epilepsy or febrile convulsions (FCs) was more frequent in patients with MRI-detected MTS (36%) as compared with patients with normal MRI (22.7%), but the difference was not significant. Antecedent FCs were more frequent (p = 0.03) in patients with MRI-detected MTS (9/39; 23%) vs those with normal MRI (5/62; 8%). Conclusions: MRI-detected mesial temporal sclerosis is often encountered in patients with sporadic benign temporal lobe epilepsy.

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 Parkinsons 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 × 10−3mm2/s) than patients with PD (median 0.79 × 10−3 mm2/s, P < 0.001), MSA‐P (median 0.79 × 10−3 mm2/s, P < 0.001), and healthy controls (median 0.80 × 10−3 mm2/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 Val108/158 Met genotype on hippocampal and prefrontal gray matter volume

A variation in catechol-O-methyltransferase (COMT) gene (Val108/158Met) 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 Val108/158Met polymorphism of the COMT gene might be responsible for individual variation in the human brain morphology.

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

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.

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 Parkinsons 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.

Abnormal pressure waves in headache sufferers with bilateral transverse sinus stenosis

Introduction: Bilateral transverse sinus stenosis (BTSS) has been reported to be associated with idiopathic intracranial hypertension without papilloedema in headache sufferers. Subjects and methods: To test the accuracy of short-term cerebrospinal fluid (CSF) pressure monitoring through a lumbar needle for detection of elevated intracranial pressure in headache sufferers with BTSS, we prospectively performed lumbar puncture in order to measure lumbar CSF opening pressures and to monitor, for 1 h, the CSF pressure in 48 consecutive headache sufferers with BTSS and in 50 consecutive headache sufferers with normal appearance of transverse sinuses or stenosis of one transverse sinus. Results: Of the 48 headache sufferers with BTSS, 18 (37.5%) had elevated CSF opening pressure and abnormal pressure waveforms, but short-term CSF pressure monitoring revealed abnormal pressure waves associated with elevated mean CSF pressure also in 26 (86.6%) out of 30 patients who had normal opening pressures. None of the 50 headache sufferers with normal appearance of transverse sinuses or stenosis of one transverse sinus had abnormal pressure waves and elevated CSF pressures. Conclusions: In this study, short-term CSF pressure monitoring through a lumbar needle revealed abnormal pressure waves and elevated mean CSF pressures in the majority of headache sufferers with BTSS who had normal CSF opening pressures. These findings demonstrate the accuracy of short-term CSF pressure monitoring through a lumbar needle in estimating CSF pressure; they also highlight that a single-spot opening pressure measurement has a low accuracy for recognition of increased intracranial pressure in headache sufferers with BTSS.

Cognitive deficits in multiple sclerosis patients with cerebellar symptoms

Background Cerebellar dysfunction is common in patients with multiple sclerosis (MS). However, neuropsychological studies of this clinical feature are lacking. Objective We investigate the neuropsychological features in relapsing-remitting MS (RR-MS) patients with and without cerebellar dysfunction. Methods Twenty-one RR-MS patients with cerebellar dysfunction (RR-MSc), characterized by prevalent ataxic gait and nystagmus, and 21 RR-MS patients without any cerebellar manifestation (RR-MSnc) pair-matched for demographical and clinical variables were studied. All patients from each group underwent an extensive battery of neuropsychological tests. Magnetic resonance imaging analysis included hyperintense fast fluid-attenuated inversion-recovery lesion load in the whole brain as well as in the four lobes separately. Results Any significant differences were detected in total and regional lesion load measurements between the two groups. RR-MSc group performed equally as well as the RR-MSnc group on many of the cognitive exploration measures. Nevertheless, the RR-MSc group performed more poorly than the RR-MSnc group on attention tests (Symbol Digit Modalities Test) and verbal fluency tests (Controlled Oral Word Association Test); neither of the test results proved to be affected by regional lesion loads. Conclusion These results highlight the importance of considering cognitive deficits associated with the presence of cerebellar symptoms in RR-MS.