Voxel-based magnetic resonance imaging study of structural brain changes in patients with idiopathic REM sleep behavior disorder

PurposeRapid eye movement (REM) sleep behavior disorder (RBD) is considered to result from dysfunction of the brain stem structures that regulate REM sleep. In this study, we investigated structural brain changes using magnetic resonance imaging (MRI) in patients with idiopathic RBD (iRBD) to determine structural brain alterations associated with the disorder.MethodsVoxel-based MRI morphometry was applied to 20 patients with iRBD and findings were compared with those from 18 age-matched controls.ResultsCompared with the controls, the patients with iRBD had significant gray matter volume reduction in the anterior lobes of the right and left cerebellum, tegmental portion of the pons, and left parahippocampal gyrus.ConclusionThe present study provides in vivo evidence suggesting that structural lesions of the brain stem are responsible for the occurrence of iRBD. In addition, the pattern of gray matter loss is consistent with morphological changes commonly observed in patients with Lewy body disease and multiple system atrophy, indicating that iRBD can share a common morphological abnormality with alpha-synucleinopathies.     

Abnormal intrinsic brain activity of the putamen is correlated with dopamine deficiency in idiopathic rapid eye movement sleep behavior disorder

ObjectivesTo investigate the changes in spontaneous neuronal activity of the striatum in idiopathic rapid eye movement (REM) sleep behavior disorder (iRBD) patients using regional homogeneity (ReHo) and amplitude of low-frequency fluctuation (ALFF) analysis. Furthermore, we tested the association between abnormal spontaneous brain activity and dopamine deficit in patients with iRBD.MethodsFifteen iRBD patients and 15 matched healthy controls received resting state magnetic resonance imaging (MRI) and neuropsychological assessments. ReHo and ALFF in subregions of the striatum were calculated and compared between groups in a voxel-by-voxel manner. In addition, 15 iRBD patients and seven healthy controls underwent dopamine transporter single photon computed emission tomography (DAT-SPECT) imaging. Correlation analysis was also performed to investigate whether the altered spontaneous brain activity could be correlated with dopamine deficiency in iRBD patients.ResultsWe found that iRBD patients, compared with healthy controls, exhibited significantly reduced ReHo in the bilateral putamen. Patients also had significantly decreased tracer uptake in the bilateral putamen and left caudate. In addition, a significantly positive correlation was observed between the mean ReHo value and the tracer uptake ratio in the left putamen of iRBD patients.ConclusionsWe detected abnormal spontaneous brain activity of the bilateral putamen in iRBD patients. These findings could be complementary to the Braak staging model and could help to clarify the pathophysiology of iRBD.     

~(18)F-FDG PET显像观察特发性快眼动睡眠期行为障碍患者脑葡萄糖代谢特点的研究

目的探讨~(18)F-FDG PET显像观察特发性快眼动睡眠期行为障碍(iRBD)患者脑葡萄糖代谢改变和iRBD脑葡萄糖代谢改变与病程间的相关性。方法纳入多导睡眠监测(PSG)确诊的iRBD患者20例(iRBD组)和年龄、性别匹配的健康对照者19例(对照组)。两组均行~(18)F-FDG PET脑显像。基于自动解剖标记模板将大脑划分为90个左右对称的脑区,计算各脑区葡萄糖代谢半定量值。对iRBD组和对照组各脑区葡萄糖代谢半定量值进行独立样本t检验;并对iRBD组脑葡萄糖代谢改变与病程行Pearson相关分析。结果 (1)与对照组比较,iRBD组的双侧背外侧额上回、双侧眶部额上回、双侧眶部额中回、双侧海马、双侧海马旁回、双侧杏仁核、左侧眶部额下回、左侧岛叶、左侧内侧与旁扣带脑回、左侧中央旁小叶、左侧苍白球的葡萄糖代谢半定量值均增高(P0.05);双侧距状裂周围皮质、双侧楔叶、双侧舌回、双侧枕上回、双侧枕中回、双侧枕下回、双侧角回、双侧颞上回、双侧颞中回、右侧颞横回的葡萄糖代谢半定量值均降低(P0.05)。Pearson相关分析结果,iRBD组双侧杏仁核、双侧颞上回、右侧楔叶、右侧枕上回、右侧颞横回、左侧海马、左侧颞中回的葡萄糖代谢半定量值与病程呈正相关(P0.05);而双侧眶部额上回、双侧眶部额中回、左侧中央旁小叶、左侧眶部额下回、左侧内侧和旁扣带回、右侧背外侧额上回、右侧海马旁回的葡萄糖代谢半定量值与病程呈负相关(P0.05)。结论 iRBD患者脑内存在疾病相关的葡萄糖代谢水平改变,有助于客观评估iRBD病情的变化。     

Abnormal baseline brain activity in low-grade hepatic encephalopathy: a resting-state fMRI study

Resting-state functional magnetic resonance imaging (fMRI) has been used to detect the alterations of spontaneous neuronal activity in various neuropsychiatric diseases, but rarely in low-grade hepatic encephalopathy (HE), a common neuropsychiatric complication of liver cirrhosis. We conducted a resting-state fMRI in 19 healthy controls, 18 cirrhotic patients without HE, and 22 cirrhotic patients with low-grade HE. The amplitude of low-frequency fluctuations (ALFF) of fMRI signal was computed to measure the spontaneous neuronal activity. Several regions showing significant ALFF differences among three groups were the precuneus, occipital lobe, left frontal lobe and anterior/middle cingulate cortex, and left cerebellum posterior lobe. Compared to controls or patients without HE, patients with low-grade HE showed decreased ALFF in the precuneus and adjacent cuneus, visual cortex, and left cerebellum posterior lobe. Compared to controls, patients with low-grade HE showed higher ALFF in both cortical and subcortical regions, including the right middle cingulate gyrus, and left anterior/middle cingulate gyrus, inferior frontal gyrus, insula lobe, parahippocampal gyrus, middle temporal gyrus and lentiform nucleus; compared to patients without HE, patients with low-grade HE showed higher ALFF in the left medial frontal gyrus and anterior cingulate gyrus, bilateral superior frontal gyrus, and right middle frontal gyrus. Moreover, correlations between ALFF changes and poor neurocognitive performances were found in patients with low-grade HE. These results suggested the existence of aberrant brain activity at the baseline state in low-grade HE, which may be implicated in the neurological pathophysiology underlying HE.     

Brain volume in male patients with recent onset schizophrenia with and without cannabis use disorders

BackgroundSchizophrenia is highly comorbid with cannabis use disorders (CUDs), and this comorbidity is associated with an unfavourable course. Early onset or frequent cannabis use may influence brain structure. A key question is whether comorbid CUDs modulate brain morphology alterations associated with schizophrenia.MethodsWe used surface-based analysis to measure the brain volume, cortical thickness and cortical surface area of a priori–defined brain regions (hippocampus, amygdala, thalamus, caudate, putamen, orbitofrontal cortex, anterior cingulate cortex, insula, parahippocampus and fusiform gyrus) in male patients with schizophrenia or related disorders with and without comorbid CUDs and matched healthy controls. Associations between age at onset and frequency of cannabis use with regional grey matter volume were explored.ResultsWe included 113 patients with (CUD, n = 80) and without (NCUD, n = 33) CUDs and 84 controls in our study. As expected, patients with schizophrenia (with or without a CUD) had smaller volumes of most brain regions (amygdala, putamen, insula, parahippocampus and fusiform gyrus) than healthy controls, and differences in cortical volume were mainly driven by cortical thinning. Compared with the NCUD group, the CUD group had a larger volume of the putamen, possibly driven by polysubstance use. No associations between age at onset and frequency of use with regional grey matter volumes were found.LimitationsWe were unable to correct for possible confounding effects of smoking or antipsychotic medication.ConclusionPatients with psychotic disorders and comorbid CUDs have larger putamen volumes than those without CUDs. Future studies should elaborate whether a large putamen represents a risk factor for the development of CUDs or whether (poly)substance use causes changes in putamen volume.     

Voxel-based analyses of gray/white matter volume and diffusion tensor data in major depression

The purpose of this study is to use voxel-based analysis to simultaneously elucidate regional changes in gray/white matter volume, mean diffusivity (MD), and fractional anisotropy (FA) in patients with unipolar major depressive disorder. We studied 21 right-handed patients and 42 age- and gender-matched right-handed normal subjects. Local areas showing significant gray matter volume reduction in depressive patients compared with controls were observed in the right parahippocampal gyrus, hippocampus, bilateral middle frontal gyri, bilateral anterior cingulate cortices, left parietal and occipital lobes, and right superior temporal gyrus. Local areas showing an increase of MD in depressive patients were observed in the bilateral parahippocampal gyri, hippocampus, pons, cerebellum, left frontal and temporal lobes, and right frontal lobe. There was no significant difference between the two groups for FA and white matter volume in the entire brain. Although there was no local area where brain volume and MD were significantly correlated with disease severity, FA tended to correlate negatively with total days depressed in the right anterior cingulate and the left frontal white matter. These results suggest that the frontolimbic neural circuit might play an important role in the neuropathology of patients with major depressive disorder.     

早发精神分裂症静息态脑功能低频振幅研究

目的通过静息态功能磁共振研究早发未用药精神分裂症患者局部脑功能低频振幅(amplitude of low-frequency fluctuation,ALFF)的变化,探讨其静息态下功能异常的脑区。方法收集20例早发未用药精神分裂症患者与20名性别、年龄、受教育年限相匹配的正常对照,分别对其进行全脑静息态功能磁共振扫描,计算ALFF值。结果与对照组相比,患者组左侧额上回、左侧楔前叶、左侧扣带回、左侧枕叶、左侧海马旁回、左侧距状沟ALFF值增高(P0.05,Alpha Sim校正),右侧颞上回和右侧小脑后叶ALFF值降低(P0.05,Alpha Sim校正)。结论早发精神分裂症患者在静息态下有多处脑区ALFF值改变,提示其在静息态下存在脑功能异常。     

反社会人格障碍男性青年大脑白质异常改变： 证据来自于基于体素脑形态测量学的DARTEL分析

SPM8 DARTEL工具包对3D脑结构成像数据对男性青年反社会人格障碍者和正常组的大脑白质结构进行基于体素的形态学分析（VBM）。结果显示,与正常对照者比较,反社会人格障碍者主要表现为双侧前额叶、右岛叶、中央前回,左右颞上回、右中央后回、右侧顶下小叶、右侧楔前叶、右枕中叶、右海马旁回及双侧扣带回等多个脑区白质体积密度增加,左颞中叶、右小脑的白质体积密度减小。相关分析显示,额内侧回的白质体积密度增加与反社会行为的评分(PDQ)有正相关。提示反社会人格障碍者存在多个脑区的白质形态学明显异常,这些异常可能与其反社会行为有关。     

Altered resting-state thalamo-occipital functional connectivity is associated with cognition in isolated rapid eye movement sleep behavior disorder

ObjectiveIsolated rapid eye movement sleep behavior disorder (iRBD) patients are at risk of cognitive impairments, however the underlying mechanism is still unclear. This study aimed to evaluate thalamo-cortical functional connectivity (FC) using resting-state functional magnetic resonance imaging (fMRI) and its correlation with cognitive dysfunction in patients with iRBD.MethodsA total 37 polysomnographies (PSGs) confirmed iRBD patients and 15 age-sex matched controls underwent resting-state fMRI and comprehensive neuropsychological assessment. Thalamo-cortical FC was evaluated by using seed-to voxel analysis and was compared between the iRBD and controls. Correlation between the average value of significant clusters and cognitive function scores in iRBD were calculated.ResultsCompared to the control subjects, patients with iRBD patients showed cognitive decline in word list recognition (p = 0.016), and constructional recall (p = 0.044). The FC analysis showed increased FC between the left thalamus and occipital regions including the right cuneal cortex, left fusiform gyrus and lingual gyrus (cluster level p < 0.05, corrected for false discovery rate). The averaged thalamo-fusiform FC value positively correlated with word list recognition after adjusting for age and sex (adjusted r = 0.347, p = 0.041).ConclusionThalamic resting state FC is altered in iRBD patients and is associated with the cognitive function. Enhancement of the thalamo-occipital FC may reflect a compensatory mechanism for cognitive impairment in iRBD.     

Alterations of the amplitude of low-frequency fluctuations in treatment-resistant and treatment-response depression: A resting-state fMRI study

Background

Patients with treatment-resistant depression (TRD) and those with treatment-response depression (TSD) respond to antidepressants differently and previous studies have commonly reported different brain networks in resistant and nonresistant patients. Using the amplitude of low-frequency fluctuations (ALFF) approach, we explored ALFF values of the brain regions in TRD and TSD patients at resting state to test the hypothesis of the different brain networks in TRD and TSD patients.

Methods

Eighteen TRD patients, 17 TSD patients and 17 gender-, age-, and education-matched healthy subjects participated in the resting-state fMRI scans.

Results

There are widespread differences in ALFF values among TRD patients, TSD patients and healthy subjects throughout the cerebellum, the visual recognition circuit (middle temporal gyrus, middle/inferior occipital gyrus and fusiform), the hate circuit (putamen), the default circuit (ACC and medial frontal gyrus) and the risk/action circuit (inferior frontal gyrus). The differences in brain circuits between the TRD and TSD patients are mainly in the cerebellum, the visual recognition circuit and the default circuit.

Conclusions

The affected brain circuits of TRD patients might be partly different from those of TSD patients.     

Analysis of Altered Baseline Brain Activity in Drug-Naive Adult Patients with Social Anxiety Disorder Using Resting-State Functional MRI

Objective

We hypothesize that the amplitude of low-frequency fluctuations (ALFF) is involved in the altered regional baseline brain function in social anxiety disorder (SAD). The aim of the study was to analyze the altered baseline brain activity in drug-naive adult patients with SAD.

Methods

We investigated spontaneous and baseline brain activities by obtaining the resting-state functional magnetic resonance imaging data of 20 drug-naïve adult SAD patients and 19 healthy controls. Voxels were used to analyze the ALFF values using one- and two-sample t-tests. A post-hoc correlation of clinical symptoms was also performed.

Results

Our findings show decreased ALFF in the bilateral insula, left medial superior frontal gyrus, left precuneus, left middle temporal gyrus, right middle temporal pole, and left fusiform gyrus of the SAD group. The SAD patients exhibited significantly increased ALFF in the right inferior temporal gyrus, right middle temporal gyrus, bilateral middle occipital gyrus, orbital superior frontal gyrus, right fusiform gyrus, right medial superior frontal gyrus, and left parahippocampal gyrus. Moreover, the Liebowitz Social Anxiety Scale results for the SAD patients were positively correlated with the mean Z values of the right middle occipital and right inferior occipital but showed a negative correlation with the mean Z values of the right superior temporal gyrus and right medial superior frontal gyrus.

Conclusion

These results of the altered regional baseline brain function in SAD suggest that the regions with abnormal spontaneous activities are involved in the underlying pathophysiology of SAD patients.     

Cortical and Subcortical Grey Matter Abnormalities in White Matter Hyperintensities and Subsequent Cognitive Impairment

Grey matter (GM) alterations may contribute to cognitive decline in individuals with white matter hyperintensities (WMH) but no consensus has yet emerged. Here, we investigated cortical thickness and grey matter volume in 23 WMH patients with mild cognitive impairment (WMH-MCI), 43 WMH patients without cognitive impairment, and 55 healthy controls. Both WMH groups showed GM atrophy in the bilateral thalamus, fronto-insular cortices, and several parietal-temporal regions, and the WMH-MCI group showed more extensive and severe GM atrophy. The GM atrophy in the thalamus and fronto-insular cortices was associated with cognitive decline in the WMH-MCI patients and may mediate the relationship between WMH and cognition in WMH patients. Furthermore, the main results were well replicated in an independent dataset from the Alzheimer''s Disease Neuroimaging Initiative database and in other control analyses. These comprehensive results provide robust evidence of specific GM alterations underlying WMH and subsequent cognitive impairment.Supplementary InformationThe online version contains supplementary material available at 10.1007/s12264-021-00657-0.     

Asymmetric Gray Matter Volume Changes Associated with Epilepsy Duration and Seizure Frequency in Temporal-Lobe-Epilepsy Patients with Favorable Surgical Outcome

MethodsVBM analysis of brain MRI using statistical parametric mapping 8 (SPM8) was performed for 30 left MTLE (LMTLE) and 30 right MTLE (RMTLE) patients and 30 age- and sex-matched healthy controls. We also analyzed the correlations between GMV changes and clinical features of MTLE patients.ResultsIn SPM8-based analyses, MTLE patients showed significant GMV reductions in the hippocampus ipsilateral to the epileptic focus, bilateral thalamus, and contralateral putamen in LMTLE patients. The GMV reductions were more extensive in the ipsilateral hippocampus, thalamus, caudate, putamen, uncus, insula, inferior temporal gyrus, middle occipital gyrus, cerebellum, and paracentral lobule in RMTLE patients. These patients also exhibited notable reductions of GMV in the contralateral hippocampus, thalamus, caudate, putamen, and inferior frontal gyrus. We observed that GMV reduction was positively correlated with several clinical features (epilepsy duration and seizure frequency in RMTLE, and history of febrile seizure in LMTLE) and negatively correlated with seizure onset age in both the RMTLE and LMTLE groups.ConclusionsOur study revealed GMV decreases in the hippocampus and extrahippocampal regions. Furthermore, the GMV reduction was more extensive in the RMTLE group than in the LMTLE group, since it included the contralateral hemisphere in the former. This difference in the GMV reduction patterns between LMTLE and RMTLE may be related to a longer epilepsy duration and higher seizure frequency in the latter.     

Precuneus-related regional and network functional deficits in social anxiety disorder: A resting-state functional MRI study

BackgroundNeuroimaging findings suggest that social anxiety disorder (SAD) may be correlated with changes in regional- or network-level brain function. However, few studies have explored alterations in intrinsic resting cerebral function in patients with SAD at both the regional and network levels, particularly focusing on the theory of mind (ToM)-related regions. This study was performed to investigate changes in neural activity and functional connectivity (FC) in ToM-related regions during the resting state in SAD patients and to determine how these alterations are correlated with the clinical symptoms of SAD.MethodsForty-three SAD patients and 43 matched healthy controls underwent resting-state functional magnetic resonance imaging (rsfMRI) scans. First, the amplitude of low-frequency fluctuation (ALFF) approach was used to explore regional activity. Then, the ToM-related region, i.e., the left precuneus, which showed altered ALFF values, was adopted as a seed for further FC analyses to assess network-level alterations in SAD. Between-group differences were compared using voxel-based two-sample t-tests (P < 0.05, with Gaussian random field correction). Pearson's correlation analyses were performed to examine relationships between alterations in ALFF and FC and clinical symptoms.ResultsCompared with the healthy controls, SAD patients showed decreased ALFF in the bilateral putamen (PUT) and left supplementary motor area (SMA) and increased ALFF in the right inferior parietal lobule (IPL), left precuneus and right cerebellar posterior lobe. Moreover, SAD patients exhibited lower connectivity between the left precuneus and the cerebellar posterior lobe, right inferior temporal gyrus (ITG), right parahippocampal gyrus (PHG) and left medial prefrontal cortex (mPFC). The altered ALFF values in the left precuneus and the hypoconnectivity between the left precuneus and left cerebellar posterior lobe were correlated with the patients' clinical symptoms (P < 0.05).ConclusionThe precuneus, a ToM-related region, was altered at both the regional and network level in patients with SAD. Pathological fear and avoidance in SAD were correlated with abnormal regional function in the precuneus, whereas depression and anxiety were primarily correlated with functional deficits in the precuneus-related network. The altered FC within the precuneus-cerebellar region may reflect an imbalance in the neuromodulation of anxiety and depressive symptoms in SAD. These findings may facilitate a greater understanding of potential SAD neural substrates and could be used to identify potential targets for further treatment.     

Alterations in the Occipital Cortex of Drug-Naïve Adults With Major Depressive Disorder: A Surface-Based Analysis of Surface Area and Cortical Thickness

Objective Advances in surface-based morphometric methods have allowed researchers to separate cortical volume into cortical thickness (CTh) and surface area (SA). Although CTh alterations in major depressive disorder (MDD) have been observed in numerous studies, few studies have described significant SA alterations. Our study aimed to measure patients’ SAs and to compare it with their CTh to examine whether SA exhibits alteration patterns that differ from those of CTh in drug-naïve patients with MDD. Methods A total of 71 drug-naïve MDD patients and 111 healthy controls underwent structural magnetic resonance imaging, and SA and CTh were analyzed between the groups. Results We found a smaller SA in the left superior occipital gyrus (L-SOG) in drug-naïve patients with MDD. In the CTh analysis, the bilateral fusiform gyrus, left middle occipital gyrus, left temporal superior gyrus, and right posterior cingulate showed thinner cortices in patients with MDD, while the CTh of the bilateral SOG, right straight gyrus, right posterior cingulate, and left lingual gyrus were increased. Conclusion Compared with the bilateral occipito-temporal changes in CTh, SA alterations in patients with MDD were confined to the L-SOG. These findings may improve our understanding of the neurobiological mechanisms of SA alteration in relation to MDD.     

Smoking and structural brain deficits: a volumetric MR investigation

Growing evidence from animal studies indicates brain-damaging properties of nicotine exposure. Investigations in humans found a wide range of functional cerebral effects of nicotine and cigarette smoking, but studies focusing on brain damage are sparse. In 22 smokers and 23 never-smokers possible differences of the cerebral structures were investigated using magnetic resonance imaging and voxel-based morphometry. Significantly smaller grey matter volume and lower grey matter density (P = 0.05, corrected) were observed in the frontal regions (anterior cingulate, prefrontal and orbitofrontal cortex), the occipital lobe and the temporal lobe including parahippocampal gyrus, in smokers than in never-smokers. Group differences of either grey matter volume or grey matter density were also found in the thalamus, cerebellum and substantia nigra, among other regions. Smokers did not show greater volumes than never-smokers in any cerebral region. Magnitude of lifetime exposure to tobacco smoke (pack-years) was inversely correlated with volume of frontal and temporal lobes and cerebellum (P = 0.001, uncorrected). The data indicate structural deficits of several cortical and subcortical regions in smokers relative to never-smokers. The topographic profile of the group differences show some similarities to brain networks known to mediate drug reinforcement, attention and working memory processing. The present findings may explain in part the frequently reported cognitive dysfunctions in chronic cigarette consumers.     

Correlation between White Matter Hyperintensities Related Gray Matter Volume and Cognition in Cerebral Small Vessel Disease

Background and AimThe relationship between severity of cerebral small vessel disease, as defined by white matter hyperintensities classification, and gray matter volume of different brain regions has not been well defined. This study aimed to investigate brain regions with significant differences in gray matter volume associated with different degrees of white matter hyperintensities in patients with cerebral small vessel disease. Meanwhile, we examined whether correlations existed between gray matter volume in different brain regions and cognitive ability.Methods110 cerebral small vessel disease patients underwent 3.0T Magnetic resonance imaging scans and neuropsychological cognitive assessments. White matter hyperintensities of each subject was graded according to Fazekas grade scale and was divided into two groups: (A) White matter hyperintensities score of 1–2 points (n = 64), (B) White matter hyperintensities score of 3–6 points (n = 46). Gray matter volume was analyzed using voxel-based morphometry implemented in Statistical Parametric Mapping 12 software.ResultsBrain regions with significant differences in gray matter volume between groups were diffused throughout the brain. Patients with high white matter hyperintensities scores exhibited decreased gray matter volume in some subregions of the frontal lobes, the temporal lobes, the parahippocampal gyrus, hippocampus and thalamus (p < 0.05). Among them, gray matter volume in the ventrolateral area of right inferior temporal gyrus, together with the right posterior parietal and occipital thalamus were positively correlated with Montreal Cognitive Assessment scores (p < 0.05). Gray matter volume in the extreme ventrolateral area of right inferior temporal gyrus along with the entorhinal cortex of left parahippocampal gyrus were positively correlated with both Montreal Cognitive Assessment and Mini-Mental Status Examination scores (p < 0.05).ConclusionsCerebral small vessel disease is considered as a whole brain disease and local white matter lesions can influence the gray matter in remote areas. Reducing the severity and progression of white matter hyperintensities may help to prevent secondary brain atrophy and cognitive impairment.     

Grey matter alterations in patients with depersonalization disorder: a voxel-based morphometry study

Background

To our knowledge, no whole brain investigation of morphological aberrations in dissociative disorder is available to date. Previous region-of-interest studies focused exclusively on amygdalar, hippocampal and parahippocampal grey matter volumes and did not include patients with depersonalization disorder (DPD). We therefore carried out an explorative whole brain study on structural brain aberrations in patients with DPD.

Methods

We acquired whole brain, structural MRI data for patients with DPD and healthy controls. Voxel-based morphometry was carried out to test for group differences, and correlations with symptom severity scores were computed for grey matter volume.

Results

Our study included 25 patients with DPD and 23 controls. Patients exhibited volume reductions in the right caudate, right thalamus and right cuneus as well as volume increases in the left dorsomedial prefrontal cortex and right somatosensory region that are not a direct function of anxiety or depression symptoms.

Limitations

To ensure ecological validity, we included patients with comorbid disorders and patients taking psychotropic medication.

Conclusion

The results of this first whole brain investigation of grey matter volume in patients with a dissociative disorder indentified structural alterations in regions subserving the emergence of conscious perception. It remains unknown if these alterations are best understood as risk factors for or results of the disorder.     

White matter volume alterations in hair-pulling disorder (trichotillomania)

Trichotillomania (TTM) is a disorder characterized by repetitive hair-pulling resulting in hair loss. Key processes affected in TTM comprise affective, cognitive, and motor functions. Emerging evidence suggests that brain matter aberrations in fronto-striatal and fronto-limbic brain networks and the cerebellum may characterize the pathophysiology of TTM. The aim of the present voxel-based morphometry (VBM) study was to evaluate whole brain grey and white matter volume alteration in TTM and its correlation with hair-pulling severity. High-resolution magnetic resonance imaging (3 T) data were acquired from 29 TTM patients and 28 age-matched healthy controls (CTRLs). All TTM participants completed the Massachusetts General Hospital Hair-Pulling Scale (MGH-HPS) to assess illness/pulling severity. Using whole-brain VBM, between-group differences in regional brain volumes were measured. Additionally, within the TTM group, the relationship between MGH-HPS scores, illness duration and brain volumes were examined. All data were corrected for multiple comparisons using family-wise error (FWE) correction at p?<?0.05. Patients with TTM showed larger white matter volumes in the parahippocampal gyrus and cerebellum compared to CTRLs. Estimated white matter volumes showed no significant association with illness duration or MGH-HPS total scores. No significant between-group differences were found for grey matter volumes. Our observations suggest regional alterations in cortico-limbic and cerebellar white matter in patients with TTM, which may underlie deficits in cognitive and affective processing. Such volumetric white matter changes may precipitate impaired cortico-cerebellar communication leading to a reduced ability to control hair pulling behavior.

     

特发性快速眼动睡眠期行为障碍纹状体微结构磁共振成像研究

目的探讨帕金森病(PD)和特发性快速眼动睡眠期行为障碍(iRBD)患者纹状体结构和白质纤维束完整性。方法联合应用基于体素的形态学分析和扩散张量成像对12例特发性快速眼动睡眠期行为障碍患者、12例帕金森病患者及10例性别、年龄和受教育程度相匹配的正常对照者进行头部MRI检查,观察纹状体结构(灰质体积)和白质纤维束完整性[部分各向异性(FA)值]变化。结果与对照组相比,iRBD组左侧尾状核灰质体积缩小(P0.005),以及左侧(P0.005)和右侧(P0.001)尾状核、右侧壳核(P0.05)FA值降低;PD组仅右侧壳核FA值降低(P0.05)。与PD组相比,iRBD组左侧尾状核灰质体积缩小(P0.001),以及左侧(P0.01)和右侧(P0.005)尾状核FA值降低。结论特发性快速眼动睡眠期行为障碍患者存在纹状体灰质体积缩小和白质纤维束完整性损害,其白质纤维束完整性损害与帕金森病具有一致性,为特发性快速眼动睡眠期行为障碍是帕金森病的临床前期提供解剖学依据。