Hooper Visual Organization Test performance in lateralized brain injury.

The Hooper Visual Organization Test (VOT) is frequently used in measuring the cognitive functioning of brain-damaged patients. It is not clear, however, whether the VOT measures general or specific neurological dysfunction, specifically those resulting from right parietal lesions. The present study addressed this issue by examining archival data from 41 brain-damaged patients who were seen in a medical hospital's acute rehabilitation unit. Patients were selected on the basis of a diagnosis of either right or left hemisphere damage, and VOT scores on these two patient groups were compared. Additionally, lesion site, as measured primarily by CT scan, was compared with VOT scores. No significant hemispheric differences were found on VOT scores. However, VOT scores, when adjusted for age and education, were significantly lower in patients with lesions involving the right parietal lobe. The implications of the findings for the use of the VOT with brain-damaged individuals are discussed.     

Associations Between Performance on the Rey-Osterrieth Complex Figure and Regional Brain Volumes in Children with and without Velocardiofacial Syndrome

Ninety-two children with velocardiofacial syndrome (VCFS), a genetic disorder caused by a microdeletion of chromosome 22q11.2 and an age, race, and gender-ratio comparable sample of 59 control participants were included in the project. Participants received an MRI as well as a comprehensive neuropsychological battery; the primary outcome measure in the current report is the Rey-Osterrieth Complex Figure (ROCF). Children with VCFS performed less well on the ROCF and have lower whole brain volume compared to controls. After controlling for whole brain volume differences, children with VCFS have bilaterally less parietal lobe gray and white matter yet more frontal lobe white matter. Brain–behavior relationships include: (a) for both groups, parietal volumes (both gray and white matter) predicted ROCF Copy Organization performance and frontal volumes (both gray and white matter) predicted ROCF Copy Accuracy performance; (b) for controls, frontal white matter also predicted ROCF Copy Organization performance; (c) ROCF Recall Organization performance was best predicted by frontal gray matter volume only in our controls; ROCF Recall Accuracy performance was best predicted by frontal gray matter volume in both groups; and (d) in children with VCFS, performance on the ROCF-Copy Structural Elements Accuracy scale was predicted by right hemisphere white matter volume. Our hypotheses were also retested using IQ-matched and whole brain volume-matched subsamples. Identical results were obtained in these analyses. Assumptions about the organization of and the localization of the brain structures that subserve specific cognitive functions in the typically developing brain may not apply in the abnormally developing brain.     

Associations between performance on the Rey-Osterrieth Complex Figure and regional brain volumes in children with and without velocardiofacial syndrome

Ninety-two children with velocardiofacial syndrome (VCFS), a genetic disorder caused by a microdeletion of chromosome 22q11.2 and an age, race, and gender-ratio comparable sample of 59 control participants were included in the project. Participants received an MRI as well as a comprehensive neuropsychological battery; the primary outcome measure in the current report is the Rey-Osterrieth Complex Figure (ROCF). Children with VCFS performed less well on the ROCF and have lower whole brain volume compared to controls. After controlling for whole brain volume differences, children with VCFS have bilaterally less parietal lobe gray and white matter yet more frontal lobe white matter. Brain-behavior relationships include: (a) for both groups, parietal volumes (both gray and white matter) predicted ROCF Copy Organization performance and frontal volumes (both gray and white matter) predicted ROCF Copy Accuracy performance; (b) for controls, frontal white matter also predicted ROCF Copy Organization performance; (c) ROCF Recall Organization performance was best predicted by frontal gray matter volume only in our controls; ROCF Recall Accuracy performance was best predicted by frontal gray matter volume in both groups; and (d) in children with VCFS, performance on the ROCF-Copy Structural Elements Accuracy scale was predicted by right hemisphere white matter volume. Our hypotheses were also retested using IQ-matched and whole brain volume-matched subsamples. Identical results were obtained in these analyses. Assumptions about the organization of and the localization of the brain structures that subserve specific cognitive functions in the typically developing brain may not apply in the abnormally developing brain.     

皮质下缺血性脑血管病的磁共振波谱研究

目的:检测皮质下缺血性脑血管病(SIVD)患者和正常对照组不同脑区脑组织的代谢水平,探讨其与认知功能损害的关系。方法:采用多体素磁共振波谱(1 H-MRS)技术评测SIVD患者(SIVD组,n=32例)和体检健康人(对照组,n=21)额叶及顶叶皮质、白质的代谢物N-乙酰天门冬氨酸(NAA)、胆碱(Cho)、肌酸(Cr);计算有关比值NAA/Cr、Cho/Cr,分析有无认知功能损害SIVD患者上述比值的变化。结果:(1)SIVD组额叶皮质、白质及顶叶皮质、白质各体素NAA/Cr比值明显低于对照组(P0.01);(2)SIVD组顶叶皮质及白质的Cho/Cr比值明显高于对照组(P0.01);(3)SIVD组有认知功能损害患者的额叶皮质和顶叶皮质、白质NAA/Cr比值显著低于无认知功能损害者(P值分别0.01、0.01、0.05),Cho/Cr比值的两者间差异无统计学意义(P0.05)。结论:SIVD患者脑组织存在NAA/Cr、Cho/Cr比值改变,且额叶皮质和顶叶皮质、白质NAA/Cr的下降与认知损害有关。     

Higher Gait Variability is Associated with Decreased Parietal Gray Matter Volume Among Healthy Older Adults

The objectives of this study were to examine the association of stride time variability (STV) with gray and white matter volumes in healthy older adults, and to determine the specific location of any parenchymal loss associated with higher STV. A total of 71 participants (mean age 69.0 ± 0.8 years; 59.7 % female) were included in this study. All participants had a 1.0 Tesla 3D T₁-weighted MRI of the brain to measure gray and white matter volumes. STV was measured at steady-state self-selected walking speed using an electronic footswitch system. We found an association between higher STV and lower gray matter volume in the right parietal lobe (e.g., angular gyrus, Brodmann area 39, cluster corrected pFWE = 0.035). There were no significant associations between STV and higher gray matter volume or change in white matter volume. To the best of our knowledge this study is the first to identify a significant association of higher STV with lower right parietal gray matter volume in healthy older adults.     

Stereoscopic visual impairment in vascular dementia.

Binocular depth perception is mediated by neural pathways that involve thalamic nuclei, the posterior parietal lobe and adjacent gyri, and white matter projections connecting these regions. Vascular dementia results from a variety of pathologic syndromes that can affect these areas, and in the current study is shown to produce associated impairment of stereoacuity or complete stereoblindness. Stereoacuity was relatively more impaired by right than left hemisphere pathology, by cortical than subcortical vascular processes, and by lesions that involved the parietal lobe. The extent of impairment was related to dementia severity as reflected by measures of intelligence, memory, and visual-spatial function. Stereoacuity was unimpaired in age-matched patients with depressive disorders.     

Sex dimorphism in gray/white matter volume and diffusion tensor during normal aging

The purpose of this study is to elucidate sex differences in global and regional gray/white matter volume, mean diffusivity (MD), and fractional anisotropy (FA) during normal aging using voxel‐based analysis. We studied 245 healthy right‐handed subjects with a wide range of ages (115 women, 22–70 years; 130 men, 21–71 years). Regarding global effects, inclusion of a quadratic age term improved the fit to data for white matter fraction and MD, but not for global gray matter volume/fraction or FA. Regarding regional effects, we found anterior‐dominant volume loss, FA decrease predominantly in the anterior white matter, and MD increase predominantly in perisylvian regions and periventricular white matter against age for both sexes. Compared with women, we found a steeper FA decline for men in the right inferior fronto‐temporal areas, extending to the anterior cingulate cortex, and an accelerated MD increase for men in the bilateral frontal, temporal, and parietal areas. There was no area in which interaction of sex with age was significant for regional volume, or in which a steeper FA decline or accelerated MD increase for women was significant. Our results provide strong evidence of sex dimorphism in global and focal diffusion characteristics during normal aging. Copyright © 2010 John Wiley & Sons, Ltd.     

Neural correlates of performance on the different scoring systems of the clock drawing test

The aim of this study was to identify brain regions associated with performance on various measures of the clock drawing test (CDT) using magnetic resonance imaging (MRI).We recruited 48 participants (four healthy, eight with mild cognitive impairment and 36 with Alzheimer's disease). Multiple regression analyses identified relationships between each CDT scoring system (Shulman CDT, Rouleau CDT and CLOX1) and regional gray matter (GM) volume.CDT scores were positively correlated with regional GM volume in the right parietal lobe for all three CDT scoring systems. In addition, CDT scores were positively correlated with regional GM volume in the bilateral posterior temporal lobes for the Shulman CDT, in the right posterior inferior temporal lobe for the Rouleau CDT and in the right posterior superior temporal lobe for the CLOX1.Although the scoring systems share commonalities, each CDT scoring system may reflect different areas of brain damage.     

The segmented regional volumes of the cerebrum and cerebellum in boys with Tourette syndrome

Neuropathological deficits are an etiological factor in Tourette syndrome (TS), and implicate a network linking the basal ganglia and the cerebrum, not a particular single brain region. In this study, the volumes of 20 cerebral and cerebellar regions and their symmetries were measured in normal boys and TS boys by brain magnetic resonance imaging. Brain magnetic resonance images were obtained prospectively in 19 boys with TS and 17 age-matched normal control boys. Cerebral and cerebellar regions were segmented to gray and white fractions using algorithm for semi-automated fuzzy tissue segmentation. The frontal, parietal, temporal, and the occipital lobes and the cerebellum were defined using the semiautomated Talairach atlas-based parcellation method. Boys with TS had smaller total brain volumes than control subjects. In the gray matter, although the smaller brain volume was taken into account, TS boys had a smaller right frontal lobe and a larger left frontal lobe and increased normal asymmetry (left>right). In addition, TS boys had more frontal lobe white matter. There were no significant differences in regions of interest of the parietal, temporal, or the occipital lobes or the cerebellum. These findings suggest that boys with TS may have neuropathological abnormalities in the gray and the white matter of the frontal lobe.     

The COMT val158met polymorphism and brain morphometry in healthy young adults

Catechol-O-methyltransferase (COMT) is the most important mechanism for dopamine degradation in the prefrontal cortex and contains a functional polymorphism (val(158)met) influencing enzyme activity. The low-activity met allele has been associated with better performance on cognitive tasks relying on the prefrontal cortex. Whether COMT also affects brain structure, is still unclear. This study investigated the relationship between the COMT val(158)met polymorphism and brain anatomy in healthy young adults. In a cross-sectional study, structural MRI data and DNA for COMT genotyping were obtained from 154 healthy young adults. Statistical Parametric Mapping software (SPM2) and optimized voxel-based morphometry were used to determine total and regional gray and white matter density differences between genotype groups, as well as age-related gray and white matter density differences within the genotype groups. We found a significant effect of COMT genotype on age-related differences in gray and white matter density in females but not in males. In female val carriers increased gray matter in the temporal and parietal lobe and the cerebellum and increased white matter in the frontal lobes were positively correlated with age; in female met homozygotes decreased gray matter density in the parietal lobe and decreased white matter density in the frontal lobes, the parahippocampal gyrus and the corpus callosum were positively correlated with age. These results suggest that the COMT val(158)met polymorphism may affect age-related differences in gray and white matter density in females.     

Normal neuroanatomical variation due to age: the major lobes and a parcellation of the temporal region

We used high-resolution MRI to investigate gray and white matter aging in the major lobes of the cerebrum (frontal, parietal, temporal, occipital) and the major sectors of the temporal lobe (temporal pole, superior temporal gyrus, infero-temporal region, parahippocampal gyrus, amygdala, hippocampus). Subjects included 87 adults between the ages of 22 and 88 years. Regions of interest were hand-traced on contiguous 1.5mm coronal slices. For the cerebrum in general, gray matter decreased linearly with age, resulting in a decline of about 9.1-9.8% between the ages of 30 and 70 years, and a decline of 11.3-12.3% by the age of 80. In contrast, white matter volume increased until the mid-50s, after which it declined at an accelerated rate. At 70 years, white matter volume was only 5.6-6.4% less than at 30 years, but by age 80, a cubic regression model predicted that the decrease would be 21.6-25.0%. Multivariate analyses indicate that the frontal gray matter was most strongly associated with age, while occipital gray and white matter were least associated. Reduction in volume in the hippocampus was best modeled by a cubic regression model rather than a linear model. No sex differences in aging were found for any regions of interest.     

Aging, sexual dimorphism, and hemispheric asymmetry of the cerebral cortex: replicability of regional differences in volume

We examined age-, sex-, and hemisphere-related differences in the cerebral cortex. Volumes of the cerebral hemispheres and 13 regions of interest (ROIs) were measured on magnetic resonance images of 200 healthy adults. The strength of association between age and volume differed across ROIs. The lateral prefrontal cortex exhibited the greatest age-related differences, whereas significantly weaker associations were observed in the prefrontal white matter, sensory-motor, and visual association regions. The hippocampal shrinkage was significant in people in their mid-fifties. The primary visual, anterior cingulate, the inferior parietal cortices, and the parietal white matter showed no age-related differences. The pattern of age-related regional differences replicated the findings previously obtained on an independent sample drawn from the same population. Men evidenced larger volumes in all ROIs except the inferior parietal lobule, even after sexual dimorphism in body size was statistically controlled. In some regions (hippocampus and fusiform gyrus) men exhibited steeper negative age-related trends than women. Although a typical pattern of global hemispheric asymmetry was observed, the direction and magnitude of regional volumetric asymmetry was as inconsistent as in the previous reports. Thus, a pattern of age-related shrinkage suggesting increased vulnerability of the lateral prefrontal cortex to aging appears stable and replicable, whereas little consistency exists in sex-related and hemispheric differences in regional cortical volumes.     

Comparison of cognitive impairment associated with major depression following stroke versus traumatic brain injury

Several studies have reported an association between cognitive impairment and major depression following stroke but failed to find a similar association among patients with traumatic brain injury (TBI). This study examined the hypothesis that age differences between stroke and TBI patients would account for the differences in the effect of major depression on cognitive function. We examined subjects' cognitive function using the Mini-Mental State Examination and compared findings among patients with stroke or TBI. Results indicated that stroke patients with major depression (N = 73) were significantly older and more cognitively impaired than similar TBI patients (N = 35), even after matching patients for lesion volume and years of education. After matching for age, however, there was no association of major depression with cognitive impairment in this relatively young stroke population. These findings support the hypothesis that age, presumably related to physiological response to brain injury, accounts for differences in the effect of major depression on cognitive function between stroke and TBI patients.     

右颞顶叶脑出血表现为纯词聋及其心理学分析

目的：分折纯词聋的神经心理学特征及探讨可能的机制。方法：对一例纯词聋病例的神经心理学检查结果及影像学特征进行分析。结果：神经心理学检查主要特征为对词语声的听辨认及复述障碍，而对非词语声(音乐声、环境声等)的听辨认基本正常；头颅CT示单一的右侧颞顶叶出血灶累及皮质下及皮质。结论：对词语声和非词语声的辨别分离是纯词聋的一个突出的特征；纯词聋的可能机制为次级感觉皮质区即Wernicke区被孤立所致，本例的机制可能为右颞叶具有相当于Wernicke区的功能而被孤立所致或右侧半球听觉区的信息不能经胼胝体传递到左侧Wernicke区所致。     

A selective working memory impairment after transcranial direct current stimulation to the right parietal lobe

The role of the posterior parietal cortex in working memory (WM) is poorly understood. We previously found that patients with parietal lobe damage exhibited a selective WM impairment on recognition but not recall tasks. We hypothesized that this dissociation reflected strategic differences in the utilization of attention. One concern was that these findings, and our subsequent interpretation, would not generalize to normal populations because of the patients’ older age, progressive disease processes, and/or possible brain reorganization following injury. To test whether our findings extended to a normal population we applied transcranial direct current stimulation (tDCS) to right inferior parietal cortex. tDCS is a technique by which low electric current applied to the scalp modulates the resting potentials of underlying neural populations and can be used to test structure–function relationships. Eleven normal young adults received cathodal, anodal, or sham stimulation over right inferior posterior parietal cortex and then performed separate blocks of an object WM task probed by recall or recognition. The results showed that cathodal stimulation selectively impaired WM on recognition trials. These data replicate and extend our previous findings of preserved WM recall and impaired WM recognition in patients with parietal lobe lesions.     

Age and gender effects on human brain anatomy: a voxel-based morphometric study in healthy elderly

The adult human brain shrinks slowly with age, but the regional specificity and tissue class specificity of this loss is unclear. Subjects (n=122) were healthy aged participants in a longitudinal cohort who undergo periodic standardized cognitive and clinical examination. Multi-spectral segmentation of magnetic resonance images into grey matter (GM), white matter (WM) and CSF was performed on cross-sectional image data using a custom template and calculated prior probability maps. Global differences were evaluated by fitting a regression model for absolute and normalized subject GM, WM, and CSF values. Global and regional patterns of GM, WM and CSF differences were assessed using optimized voxel-based morphometry (VBM). GM volume decreased with age at a rate of 2.4 cm(3)/year (-0.18%/year); CSF increased by 2.5 cm(3)/year (0.20%/year). Regression analyses showed no significant decrease in WM volume, but a focal WM decrease with age was detected in the anterior corpus callosum using VBM. Diffuse reductions of GM volume were seen with age in the frontal, parietal, and temporal cortex, cerebellum and basal ganglia. Relative regional differences in cortical GM volume with age occurred in the frontal, parietal and temporal lobes, but not in medial temporal lobe or in posterior cingulate. We did not observe significant gender effects. These findings establish a baseline for comparison with pathologic changes in human brain volume between ages 58 and 95 years.     

Brain structure in asymptomatic FMR1 premutation carriers at risk for fragile X-associated tremor/ataxia syndrome

Fragile X-associated tremor/ataxia syndrome (FXTAS), a late-onset movement disorder affecting FMR1 premutation carriers, is associated with cerebral and cerebellar lesions. The aim of this study was to test whether computational anatomy can detect similar patterns in asymptomatic FMR1 premutation carriers (mean age 46.7 years) with qualitatively normal -appearing grey and white matter on brain MRI. We used a multimodal imaging protocol to characterize brain anatomy by automated assessment of gray matter volume and white matter properties. Structural changes in the hippocampus and in the cerebellar motor network with decreased gray matter volume in lobule VI and white matter alterations of the corresponding afferent projections through the middle cerebellar peduncles are demonstrated. Diffuse subcortical white matter changes in both hemispheres, without corresponding gray matter alterations, are only identified through age × group interactions. We interpret the hippocampal fimbria and cerebellar changes as early alterations with a possible neurodevelopmental origin. In contrast, progression of the diffuse cerebral hemispheric white matter changes suggests a neurodegenerative process, leading to late-onset lesions, which may mark the imminent onset of FXTAS.     

Does the Clock Drawing Test have focal neuroanatomical correlates?

The Clock Drawing Test (CDT) is widely used in clinical neuropsychological practice. The CDT has been used traditionally as a "parietal lobe" test (e.g., Kaplan, 1988), but most empirical work has focused on its sensitivity and specificity for detecting and differentiating subtypes of dementia. There are surprisingly few studies of its neuroanatomical correlates. The authors investigated the neuroanatomical correlates of the CDT, using 133 patients whose lesions provided effective coverage of most of both hemispheric convexities and underlying white matter. On the CDT, 30 subjects were impaired and 87 were unimpaired (16 were "borderline"). Impairments on the CDT were associated with damage to right parietal cortices (supramarginal gyrus) and left inferior frontal-parietal opercular cortices. Visuospatial errors were predominant in patients with right hemisphere damage, whereas time setting errors were predominant in patients with left hemisphere lesions. These findings provide new empirical evidence regarding the neuroanatomical correlates of the CDT, and together with previous work, support the use of this quick and easily administered test not only as a screening measure but also as a good index of focal brain dysfunction.     

Voxel-based assessment of gray and white matter volumes in Alzheimer's disease

Using the study-specific templates and optimized voxel-based morphometry (VBM), this study investigated abnormalities in gray and white matter to provide depiction of the concurrent structural changes in 13 patients with Alzheimer's disease (AD) compared with 14 age- and sex-matched normal controls. Consistent with previous studies, patients with AD exhibited significant gray matter volume reductions mainly in the hippocampus, parahippocampal gyrus, insula, superior/middle temporal gyrus, thalamus, cingulate gyrus, and superior/inferior parietal lobule. In addition, white matter volume reductions were found predominately in the temporal lobe, corpus callosum, and inferior longitudinal fasciculus. Furthermore, a number of additional white matter regions such as precentral gyrus, cingulate fasciculus, superior and inferior frontal gyrus, and sub-gyral in parietal lobe were also affected. The pattern of gray and white matter volume reductions helps us understand the underlying pathologic mechanisms in AD and potentially can be used as an imaging marker for the studies of AD in the future.     

Stereological Investigation of Age‐Related Changes of the Capillaries in White Matter

We, for the first time, investigated the age‐related changes of the capillaries in white matter using immunohistochemistry and stereological techniques. Ten young female (7 months) and 10 aged female (27 months) rats were used. The total length, total volume, and total surface area of the capillaries in white matter of aged rats were all significantly lower than those of young rats. The age‐related changes of the capillaries in white matter may have important implications for age‐related white matter atrophy and age‐related cognitive impairments. Anat Rec 293:1400–1407, 2010. © 2010 Wiley‐Liss, Inc.