Smaller frontal lobe white matter volumes in depressed adolescents.

BACKGROUND: Prior studies have demonstrated reduced frontal lobe volumes in depressed adolescents. In this study, frontal lobe gray and white matter volumes in adolescents with major depressive disorder were evaluated. METHODS: Nineteen depressed and thirty-eight healthy comparison adolescents were recruited for a magnetic resonance imaging study. Images were segmented into gray matter, white matter, and cerebrospinal fluid. Morphometric measurements of the whole brain and frontal lobe region were completed. RESULTS: Whole brain volumes were significantly smaller in depressed subjects compared with the healthy comparison subjects. Significantly smaller frontal white matter volumes and significantly larger frontal gray matter volumes were found in the depressed subjects, after controlling for age and whole brain volume. CONCLUSIONS: These results are consistent with the hypothesis that a deficit in frontal volume exists during cortical development in adolescents with depression. Further studies are needed to assess whether volume differences resolve over time and the extent to which these differences influence response to treatment.     

MRI正常额叶癫(癎)患者的MR扩散张量成像研究

目的应用MR扩散张量成像（DTI）技术探讨MRI正常的额叶癫痢患者与运动相关白质是否存在隐匿性病变。方法对临床确诊的16例MRI正常的额叶癫痫患者发作间期和30例健康志愿者行常规MRI和DTI检查,定量测量额叶皮层下白质、胼胝体膝部和压部、内囊前肢和后肢及外囊的平均扩散系数（DCavg）和部分各向异性（FA）值,并进行统计学分析。结果MRI正常的额叶癫痴患者额叶皮层下白质、胼胝体膝部区域的DCavg值显著高于正常人（P〈0．01）,皮层下白质的FA值显著低于正常人（P〈0．01）,胼胝体膝部的FA与正常人无差异。结论MRI正常的额叶癫痫患者存在额叶隐匿性损害DTI为发现致痢灶提供理论依据,具有临床应用价值。     

Contributors to white matter damage in the frontal lobe in Alzheimer's disease

Abnormalities of cerebral white matter are present in a majority of patients with Alzheimer's disease (AD) and probably contribute to motor dysfunction and cognitive impairment. The white matter abnormalities are usually attributed to degenerative vascular disease and cerebral amyloid angiopathy (CAA) but the evidence is scanty or inconclusive. In the present study we examined sections of frontal lobe from 125 autopsy-confirmed cases of AD and assessed the relationship of degenerative large and small vessel disease, CAA, parenchymal Abeta load and APOE genotype, to several objective measures of white matter damage: extent of immunolabelling for glial fibrillary acidic protein (GFAP), axonal accumulation of amyloid precursor protein (APP), axon density in superficial and deep white matter, and intensity of staining for myelin. We found no association between atherosclerosis, arteriolosclerosis, CAA or APOE genotype and white matter damage. However, labelling of white matter for GFAP correlated strongly with the parenchymal Abeta load (P = 0.0003) and with APP accumulation (P = 0.008). Our findings suggest that severity of frontal white matter damage in AD is closely related to parenchymal Abeta load and that in most cases the contribution of degenerative vascular disease, CAA and APOE is relatively minor.     

Sex differences in frontal lobe white matter microstructure: a DTI study

There is evidence that the brains of men and women are structurally different, but there are few data regarding possible sex differences in white matter microstructure. Using diffusion tensor imaging we assessed fractional anisotropy (FA) in the frontal lobe white matter on contiguous 5 mm slices in nine healthy male and 11 healthy female adults. Overall, women had higher FA in the left frontal lobe compared to men and a leftward asymmetry of FA in contrast to men, who showed no hemispheric asymmetry. Among women, greater leftward asymmetry of frontal lobe FA correlated significantly with better verbal comprehension and memory functioning. Our findings may be indicative of increased directional coherence and/or density of left hemisphere white matter fibers and a leftward asymmetry of this structural integrity among women compared to men.     

Disproportionate atrophy of cerebral white matter in chronic alcoholics

Morphometric analysis of postmortem brains from chronic ethyl alcohol abusers and controls was performed to determine the regional distribution and extent of atrophy in the cerebral hemispheres of alcoholics. This study was performed by digitizing photographs of coronal slices of the brains to compute the cross-sectional area of the cerebrum, cerebral cortex, subcortical nuclei, cerebral white matter, and the ventricular system at five standardized levels. Although the alcoholics and controls had similar demographic features and mean brain weights, brains from the alcoholic group showed mild but consistent atrophy of the cerebral cortex (2.5% to 4.2% reductions in cross-sectional area at all five levels), moderate atrophy of cerebral white matter (6.1% to 17.5% reductions), and enlargement of the ventricular system (31.8% to 71.9% increases). There were no differences in the sizes of subcortical nuclei. The absolute increase in the size of the ventricles in the alcoholic group was roughly equal to the amount of tissue lost in cerebral white matter, thereby representing hydrocephalus ex vacuo. The disproportionate loss of cerebral white matter relative to cerebral cortex suggests that a major neurotoxic effect of chronic alcohol intoxication in the central nervous system is axonal degeneration.     

MRI parcellation of the frontal lobe in boys with attention deficit hyperactivity disorder or Tourette syndrome

Dysfunction of frontal-striatal-thalamic-frontal circuitry has been hypothesized to underlie both attention deficit hyperactivity disorder (ADHD) and Tourette syndrome (TS). Several research groups have therefore used anatomic magnetic resonance imaging (aMRI) to obtain volumetric measurements of subregions of the frontal lobe in these disorders. Most previous studies have relied on subparcellation methods that utilize callosal landmarks to derive subregions of the frontal lobe. In contrast, we present here an investigation of frontal lobe morphometry in ADHD and TS based on a reliable frontal subparcellation protocol that combines contiguous sulcal/gyral boundaries to derive frontal lobe modules based on prior functional studies. This highly reliable procedure subdivides the frontal lobe into five major modules: prefrontal, premotor, motor (precentral gyrus), anterior cingulate, and deep white matter. The first four modules are also segmented into gray and gyral white matter compartments. The protocol was applied to T1-weighted, SPGR coronal MRI images of 13 school-aged boys with ADHD, 13 boys with TS, and 13 age- and gender-matched controls. In ADHD, we found volumetric reductions in both the gray and white matter of the prefrontal cortex. These findings, in conjunction with previous reports on basal ganglia abnormalities, suggest that prefrontal-striatal pathways may be anomalous in ADHD. In TS, we found volumetric decreases in the left deep frontal white matter. Decreases in deep white matter suggest the presence of abnormalities in long associational and projection fiber bundles in TS. The findings of this study both confirm and extend our knowledge of the neurobiology of ADHD and TS, indicating that the reliable parcellation method presented has the potential of increasing our understanding of the role of the frontal lobe in developmental and psychiatric disorders.     

Semantic priming in patients with right frontal lobe lesions.

Patients with unilateral, right frontal lobe damage (N=13) and matched controls (N=20) performed a task of lexical ambiguity resolution in order to explore the contribution of right frontal regions to lexical-semantic priming. Word triplets consisting of balanced homographs were presented to participants in four conditions: concordant, discordant, neutral, and unrelated. Controls demonstrated facilitation for concordant meanings of homographs, as evidenced by their faster reaction times in the concordant relative to the unrelated (baseline) condition, as well as a lack of facilitation for the discordant meaning relative to the neutral and concordant conditions. Results in patients with right frontal lobe damage differed depending on the site of the lesion. Patients with lesions restricted to the right medial frontal lobe only showed facilitation in the neutral condition, while those with lesions encroaching upon the right dorsolateral region demonstrated facilitation of both discordant and concordant meanings relative to the baseline condition. These results support a role for the right frontal lobe in semantic priming and suggest possible specialization within the right prefrontal cortex for the processing of lexical-semantic information.     

Psychosis and epileptic seizures in Wilson's disease with predominantly white matter lesions in the frontal lobe

Although psychiatric symptoms are not rare in Wilson's disease (WD), their association with epileptic seizures has not been reported. We describe three patients with such clinical manifestations who had predominantly cerebral white matter lesions in the frontal lobe. There were two men and one woman with ages ranging from 20 to 26 yr. The early presentations were psychiatric symptoms and epileptic seizures with or without secondary generalization. The psychiatric features were usually misinterpreted as schizophrenia-like disease and the diagnosis was delayed. The cerebral white matter lesions on magnetic resonance imaging (MRI) were usually asymmetric and mainly restricted to the frontal lobes. The present observation suggests that early onset of psychiatric manifestations and seizures commonly occur in WD with frontal white matter lesions.     

Unilateral spatial neglect due to right frontal lobe haematoma.

Two patients with unilateral spatial neglect caused by right frontal lobe lesions underwent cerebral blood flow studies. A 54-year-old, right-handed woman developed left hemiplegia and frontal lobe neglect associated with cerebral haemorrhage after surgical excision of a frontal tumour. A 66-year-old, right-handed woman developed a haemorrhage in the right frontal lobe caused by rupture of an aneurysm. This was followed by left hemiplegia and frontal lobe neglect. In both cases, 123I-iodoamphetamine single photon emission CT disclosed a reduction in regional cerebral blood flow localised along the circumference of the haematoma in the frontal lobe, but did not reveal any lesions in the parieto-occipital junction. These findings suggest that, in these two cases, the frontal lobe neglect was caused by lesions confined to the frontal lobe.     

Increased microstructural white matter correlations in left,but not right,temporal lobe epilepsy

Microstructural white matter tract correlations have been shown to reflect known patterns of phylogenetic development and functional specialization in healthy subjects. The aim of this study was to establish intertract correlations in a group of controls and to examine potential deviations from normality in temporal lobe epilepsy (TLE). We investigated intertract correlations in 28 healthy controls, 21 left TLE (LTLE) and 23 right TLE (RTLE). Nine tracts were investigated, comprising the parahippocampal fasciculi, the uncinate fasciculi, the arcuate fasciculi, the frontoparietal tracts, and the fornix. An abnormal increase in tract correlations was observed in LTLE, while RTLE showed intertract correlations similar to controls. In the control group, tract correlations increased with increasing fractional anisotropy (FA), while in the TLE groups tract correlations increased with decreasing FA. Cluster analyses revealed agglomeration of bilateral pairs of homologous tracts in healthy subjects, with such pairs separated in our LTLE and RTLE groups. Discriminant analyses aimed at distinguishing LTLE from RTLE, revealing that tract correlations produce higher rates of accurate group classification than FA values. Our results confirm and extend previous work by showing that LTLE compared to RTLE patients display not only more extensive losses in microstructural orientation but also more aberrant intertract correlations. Aberrant correlations may be related to pathologic processes (i.e., seizure spread) or to adaptive processes aimed at preserving key cognitive functions. Our data suggest that tract correlations may have predictive value in distinguishing LTLE from RTLE, potentially moving diffusion imaging to a place of greater prominence in clinical practice. Hum Brain Mapp, 36:85–98, 2015. © 2014 Wiley Periodicals, Inc.     

Environmental reduplication associated with right frontal and parietal lobe injury.

Four patients with environmental reduplication, a specific form of spatial disorientation and confabulation are described. The patients maintained that their hospital rooms were located in their homes. Each patients had evidence of right frontal or right parietal injury based upon computed tomography, neurosurgery, and neuropsychological testing. The factors associated with environmental reduplication were: impaired spatial perception and visual memory, inability of the patients to recognise the inconsistency between their believed location and their actual location, confusion soon after admission to hospital, and a strong desire to be at home.     

Giant aneurysm causing frontal lobe syndrome

Summary A 67-year-old patient with a completely thrombosed giant aneurysm of the anterior communicating artery is described. The only neurological findings were a disturbance of stance and gait and slight bilateral grasp reflexes. He had had the features of a frontal lobe psychotic syndrome for more than 12 years. Computed tomography demonstrated a primarily hyperdense calcified suprasellar space-occupying lesion. Magnetic resonance imaging proved valuable in establishing the correct diagnosis, which was confirmed post mortem.     

Glial cell changes in the white matter in temporal lobe epilepsy.

Temporal lobe gliosis and neuronal loss are pathological hallmarks of complex partial seizures. However, the specificity of glial cell changes is not clear. To assess this we studied surgically resected temporal lobes containing either medial temporal sclerosis (MTS) or temporal lobe epilepsy with tumour (TLET) and compared them with idiopathic epilepsy cases and normal controls. We quantitatively assessed glial cell density and mean nuclear volume in the white matter of various temporal gyri and the deep white matter. There was an increase in mean glial cell nuclear volume in MTS and TLET cases in the white matter of superior temporal gyrus, parahippocampal gyrus and deep white matter but not in the white matter of the middle temporal gyrus. In contrast, the densities of glial cells immunopositive for glial fibrillary acidic protein in the MTS and TLET groups were reduced in all white matter regions when compared with the controls. These changes may indicate that glial cells in the white matter have an active role to play in epilepsy pathogenesis.     

Ictal kissing in a patient with right frontal lobe epilepsy

When performing pre‐surgical evaluation of patients with refractory epilepsy, the analysis of seizure semiology is one of the key elements used to generate a hypothesis about the location of the epileptogenic zone. Ictal kissing is a very rarely observed ictal automatism described in patients with temporal lobe epilepsy. We present a 62‐year‐old man who was referred to our epilepsy centre for comprehensive evaluation. During prolonged video‐EEG monitoring, six focal‐onset hyperkinetic seizures were registered. In five seizures, the patient repeatedly produced sonorous kisses “into the air”. Initial ictal EEG pattern consisted of rhythmic theta or alpha activity at the right fronto‐polar and fronto‐medial electrodes. MRI depicted focal cortical dysplasia located in the right prefrontal medial cortex. This case suggests that ictal kissing can also occur in the setting of right frontal lobe epilepsy; we therefore believe that this observation expands the anatomo‐clinical correlation for this rare ictal automatism. [Published with video sequences].     

Luria''s frontal lobe syndrome: psychological and anatomical considerations.

Luria has described a syndrome of disinhibited and impulsive behaviour, in which the patient is unable to follow sequential instructions. This he attributes to localised frontal lobe damage. However, group studies of patients with focal lesions of the frontal lobes fail to reveal such a syndrome. A patient is described who displayed a form of Luria's syndrome temporarily. Psychometric and post mortem evidence indicate that the syndrome arises only under conditions of more global cerebral dysfunction.     

Inferior frontal white matter volume and suicidality in schizophrenia

The neurobiology of suicidality in schizophrenia is largely unknown. We therefore assessed gray and white matter volumes associated with past suicidality and current self-aggression in schizophrenia. Fifty-five outpatients with schizophrenia (n=55) and healthy controls (n=55), matched for age, gender and handedness, were recruited. Ten patients had a life-time history of one or more suicide attempts. Current self-aggression was assessed using the Modified Overt Aggression Scale. High resolution structural magnetic resonance images were analyzed by voxel-based morphometry. We found significantly larger inferior frontal white matter volumes bilaterally in patients with a previous suicide attempt as compared with those patients without a history of suicidality. No other significant white or gray matter volume differences were observed. White matter volume in these regions did not differ between healthy controls and those patients without a previous suicide attempt. Furthermore, among patients, the level of current self-aggression showed a significant positive correlation with white matter volume in the same regions. Inferior frontal white matter alterations in fronto-temporo-limbic circuits may be associated with suicidality and self-aggression in schizophrenia.