The syndrome of combined polar and paramedian thalamic infarction

BACKGROUND: Occlusion of the polar or the paramedian arteries of the thalamus usually leads to distinct infarcts with specific clinical and imaging correlates. However, vascular variation is such that in up to one third of humans, the polar artery is missing and its territory taken over by the paramedian arteries. OBJECTIVE: To provide attention to the corresponding stroke syndrome of combined polar and paramedian thalamic infarction. METHODS: We studied combined polar-paramedian thalamic infarction in 12 patients (6 right-sided lesions, 3 left-sided lesions, and 3 bilateral lesions) who were selected from 208 consecutively registered patients with thalamic strokes in the Lausanne Stroke Registry. RESULTS: The clinical manifestation included executive dysfunction, apathy, and memory impairment in all patients, with eye movement disturbances in 10 patients (5 with right-sided lesions, 2 with left-sided lesions, 3 with bilateral lesions); acutely impaired consciousness in 11 patients (5 with right-sided lesions, 3 with left-sided lesions, 3 with bilateral lesions); aphasic disturbances in 8 patients (2 with right-sided lesions, 3 with left-sided lesions, 3 with bilateral lesions), including nonfluent aphasia in 1 patient (with left-sided lesions); dysarthria in 5 patients (4 with right-sided lesions, 1 with bilateral lesions); constructional apraxia in 5 patients (with right-sided lesions); mild hemiparesis in 4 patients (2 with right-sided lesions, 2 with left-sided lesions); dyscalculia in 3 patients (1 with left-sided lesions,1 with right-sided lesions, 1 with bilateral lesions); limb dystonia or asterixis in 2 patients (1 with right-sided lesions, 1 with bilateral lesions); mild hemisensory loss in 2 patients (1 with right-sided lesions, 1 with left-sided lesions); hemiataxia in 1 patient (with right-sided lesions); and ideomotor apraxia in 1 patient (with left-sided lesions). Follow-up showed severely disabling, persistent amnesia in 7 patients (4 with right-sided lesions, 3 with bilateral lesions) and persistent eye movement dysfunction in 5 patients (2 with right-sided lesions, 1 with left-sided lesions, 2 with bilateral lesions). The most common etiology appeared to be cardioembolism, followed by artery-to-artery embolism and presumed small-artery disease. CONCLUSIONS: Key features of this syndrome included amnesia preceded by a period of altered consciousness, and vertical eye movement disturbances. The severe and persistent amnesia may be due to coexisting damage to the anterior and dorsomedial nuclei.     

Lesion lateralization in patients with epilepsy and precocious destructive insults

Destructive brain lesions that occur early in development are often unilateral or asymmetric. We analyzed the lateralization of lesions among a previously reported series of 51 patients with three kinds of destructive lesions based on their topography: specific arterial territory (AT), arterial borderzone territory (Bdz), hemispheric (H). Five patients (all from group Bdz) had bilateral nonlateralizing lesions. The distributions of left- and right-sided lesions were distinct among the groups (P=0.014): in group H, all patients except one presented with right-sided lesions (89%); in group Bdz, left-sided lesions (53%) were more frequent than right-sided lesions (17.7%); in group AT, left- and right-sided lesions were more equally distributed (56 and 44%). Our study suggests that there is a trend toward lesion lateralization among patients with different patterns of precocious destructive lesions. Differences in cerebral maturation and vulnerability between the hemispheres is a possible factor explaining lesion lateralization in early life insults.     

Morphological aspects of aetiology and the course of infantile spasms (West-syndrome)

The present study using the results of the postmortem examination of twenty-four children, who had infantile spasms (West-Syndrome), gives a view of the aetiology and course of the West-Syndrome. According to the time of occurrence of the lesions three groups could be established: one group of six cases with only embryofetal lesions, one group of ten cases with combined embryofetal and peri/postnatal lesions and one group of eight cases with only peri/postnatal lesions. It is significant, that the time of onset of infantile spasms depends on time of manifestation of lesions. In the groups with combined embryofetal and peri/postnatal lesions the seizures were manifested at the same time as in the cases with isolated embryofetal lesions. Even in the group with combined lesions, microdysgenesis was interpreted as being embryofetal. These embryofetal lesions, as opposed to the peri/postnatal lesions thus appear to dominate and thereby to be pathoplastic. From this correlation two thirds of the cases of infantile spasms can be regarded as fetal epilepsies. The question is open if the infantile spasms which are manifested later on and develop mostly a Lennox-Syndrome indeed should be classified as a separate group together with the isolated peri/postnatal lesions.     

Unilateral fimbria/fornix lesions attenuate behavioral symptoms induced by subsequent dorsal hippocampal lesions in rats

Adult rats were given a unilateral fimbria-fornix (5, 10, 15 micrograms colchicine or electrolytic) lesion 30 days before a restricted bilateral dorsal hippocampal lesion to assess the behavioral effects of temporally and structurally spaced lesions. The rats were tested 30 days after the second-stage surgery in the Hebb-Williams maze learning task. All rats with lesions were impaired in comparison with sham-operated control rats. However, those which sustained electrolytic or 5 micrograms colchicine fimbria-fornix lesions before hippocampal lesions were less impaired than rats which received hippocampal lesions alone or hippocampal lesions preceded by fimbria-fornix lesions with larger doses of colchicine.     

Neuropsychological impairment in multiple sclerosis patients: the role of (juxta)cortical lesion on FLAIR

In this study we evaluated the correlation between neuropsychological impairment (measured with the Brief Repeatable Battery Neuropsychological Tests) and (juxta)cortical lesions detected with FLAIR and the relative sensitivity of the FLAIR sequence compared to spin-echo MRI sequences in detecting (juxta)cortical MS lesions. A total of 39 patients with definite MS were evaluated by MRI with a conventional and fast spin echo sequence and fast FLAIR sequence, and neuropsychological tests of the Brief Repeatable Battery Neuropsychological tests were performed. The Z-score of all subtests were used to calculate a Cognitive Impairment Index. The results show that a high number of (juxta)cortical lesions is detected with thin slice FLAIR (30% of all lesions seen). This percentage was not superior to spin-echo, reflecting the thin slice thickness (3 mm) we used. The lesions detected with FLAIR were to a certain degree different ones than the lesions detected with the other techniques. While the number of non-cortical lesions correlated with the expanded disability status scale (r=0.32, P=0.045), the number of (juxta)cortical lesions detected with the FLAIR showed a correlation (r=0.34, P=0.035) with the Cognitive Impairment Index. Our study underlines the high number of (juxta)cortical lesions in MS and the value of thin slice FLAIR sequence to detect such lesions with MRI. It also stresses the importance of (juxta)cortical lesions on determining neuropsychological impairment. Multiple Sclerosis (2000) 6 280 - 285     

Dream recall in patients with focal cerebral lesions

Rare case reports have indicated that brain lesions may cause a loss of dream recall. We investigated reports of dream recallers with acute unilateral brain lesions who did not have clinical agnosia and examined 53 patients with such focal lesions clinically and radiologically. Patients with posterior lesions showed a frequent loss of dream recall while those with anterior lesions rarely did so. The cessation of dream recall was associated with defective performance in tests for visuoperceptive functions. We concluded that patients with acute posterior hemispheric lesions frequently lose their ability to recall dreams.     

Use of perfusion- and diffusion-weighted imaging in differential diagnosis of acute and chronic ischemic stroke and multiple sclerosis

OBJECTIVE: To investigate differences in lesions and surrounding normal appearing white matter (NAWM) by perfusion-weighted imaging (PWI) and diffusion-weighted imaging (DWI) in patients with acute and chronic ischemic stroke and multiple sclerosis (MS). METHODS: Study subjects included 45 MS patients, 22 patients with acute ischemic stroke and 20 patients with chronic ischemic stroke. All subjects underwent T2-weighted imaging (WI), flair attenuated inversion recovery (FLAIR), DWI and dynamic contrast enhanced PWI. Apparent diffusion coefficient (ADC) and mean transit time (MTT) maps were generated and values were calculated in the acute and chronic ischemic and demyelinating lesions, and in NAWM for distances of 5, 10 and 15 mm. Fifty-three acute ischemic and 33 acute demyelinating lesions, and 775 chronic ischemic and 998 chronic demyelinating lesions, were examined. Univariate, multivariate and data mining analyses were used to examine the feasibility of a prediction model between different lesion types. Correctly and incorrectly classified lesions, true positive (TP), false positive (FP) and precision rates were calculated. RESULTS: Patients with acute ischemic lesions presented more prolonged mean MTT values in lesions (p=0.002) and surrounding NAWM for distances of 5, 10 and 15 mm (all p<0.0001) than those with acute demyelinating lesions. In multinomial logistic regression analysis, 65 of 86 acute lesions were correctly classified (75.6%). The TP rates were 81.1% for acute ischemic lesions and 66.7% for acute demyelinating lesions. The FP rates were 33.3% for acute ischemic and 18.9% for acute demyelinating lesions. The precision was 79.6% for classification of acute ischemic lesions and 68.8% for prediction of acute demyelinating lesions. The logistic model tree decision algorithm revealed that prolonged MTT of surrounding NAWM for a distance of 15 mm (> or =7459.2 ms) was the best classifier of acute ischemic versus acute demyelinating lesions. Patients with chronic ischemic lesions presented higher mean ADC (p<0.0001) and prolonged MTT (p=0.013) in lesions, and in surrounding NAWM for distances of 5, 10 and 15 mm (all p<0.0001), compared to the patients with chronic demyelinating lesions. Data mining analyses did not show reliable predictability for correctly discerning between chronic ischemic and chronic demyelinating lesions. The precision was 56.7% for classification of chronic ischemic and 58.9% for prediction of chronic demyelinating lesions. DISCUSSION: We found prolonged MTT values in lesions and surrounding NAWM of patients with acute and chronic ischemic stroke when compared to MS patients. The use of PWI is a promising tool for differential diagnosis between acute ischemic and acute demyelinating lesions. The results of this study contribute to a better understanding of the extent of hemodynamic abnormalities in lesions and surrounding NAWM in patients with MS.     

A quantitative relationship between the extent of localized cerebral lesions and the intellectual and behavioural deficiency in children

Summary In an investigation of 51 children with localized forebrain lesions (25 left hemispheric, 15 right hemispheric and 11 bilateral) a significant relationship between the extent of the cerebral lesion (quantitatively determined by means of computerized tomography scans) and the IQ was found, but only in children with lesions after age 5: there was a diminution of 3 (British Ability Scales and Porteus Mazes) to 4 (Wechsler test) points of 10 for a 1% increased brain lesion. There was no correlation between the extent of the lesion and IQ in children with early lesions. The IQ of the children with early lesions (up to year 4) was significantly lower than that of children with later lesions of the same extent.There was a highly significant correlation between behavioural problems (assessed by Conners Teacher Rating Scale) and diminution of IQ. There was a significant correlation between the extent of lesion and behavioural problems in lesions after year 5, but not in early lesions. While the correlation between intellectual-behavioural impairment and the extent of cerebral lesions can be explained by multiple localisation of functions, the lack of this correlation in early lesions and the more severe impairment by earlier lesions may be due to an interaction of brain development with social and lesional factors. Since each part of the brain may act as a stimulus for the development of other parts, even small differences in the lesions (and/or in the environment) may result in large behavioural differences (hypothesis of the developing brain as an amplifier for differences in the stimuli).     

Differential effects of two visual cortical lesions in the rabbit

Acquisition and retention of brightness and pattern discrimination in rabbits with lesions of visual cortical areas Visual I or I + II was investigated. Rabbits with such lesions did not differ from normals in learning a brightness discrimination but those with Visual I + II lesions showed an impairment in retention of a preoperatively learned brightness discrimination. Rabbits with Visual I lesions were significantly impaired in acquisition of a pattern discrimination and rabbits with both lesions showed even more severe impairment on this task. The role of posterior thalamic nuclei and extrastriate cortex in visual discrimination is discussed.     

Dichotic listening ear preference after childhood cerebral lesions

Patients with unilateral (right or left) nonprogressive cerebral lesions acquired in infancy (before age one) or childhood (ages one to fifteen) were given a dichotic listening test. The two groups of patients with the childhood lesions showed the pattern of ear preference typically seen after hemispheric lesions in adults; loss of right ear preference after left hemisphere (LH) lesions, and enhanced right ear preference after right hemisphere (RH) lesions. The two groups of patients with the very early lesions failed to show any consistent ear preference or to differ from one another in ear preference. It is postulated that this lack of a consistent lesion effect following very early lateralized brain lesions is due to the greater degree of functional reorganization that takes place after such lesions.     

Temporal and spatial context memory in patients with focal frontal, temporal lobe, and diencephalic lesions

Patients with focal frontal, temporal lobe, or diencephalic lesions were investigated on measures of temporal (recency) and spatial (position) context memory, after manipulating exposure times to match recognition memory for targets (pictorial stimuli) as closely as possible. Patients with diencephalic lesions from an alcoholic Korsak off syndrome showed significant impairment on the temporal context (recency) task, as did patients with frontal lesions penetrating the dorsolateral frontal cortex, according to MRI (and PET) evidence. Patients with temporal lobe lesions showed only a moderate (non-significant) impairment on this task, and patients with medial frontal lesions, or large frontal lesions not penetrating the dorsolateral cortical margins, performed as well as healthy controls at this task. On the spatial context memory task, patients with lesions in the temporal lobes showed significant impairment, and patients with right temporal lesions performed significantly worse than patients with left temporal lesions. Patients with diencephalic lesions showed only a modest (non-significant) impairment on this task, and the frontal lobe group performed normally. When a group of patients with temporal lobe lesions resulting from herpes encephalitis were examined separately, an identical pattern of results was obtained, the herpes group being significantly impaired on spatial memory and showing a trend towards impairment for temporal context memory. There were strong correlations between anterograde memory quotients and context memory performance (despite the use of an exposure time titration procedure) and a weak association with one frontal/executive task (card-sorting perseverations). It is predicted that correlations between temporal context memory and frontal/executive tasks will be greater in samples of patients all of whom have frontal lesions invading the dorsolateral cortical margin.     

Severe learning impairment caused by combined immunotoxic lesion of the cholinergic projections to the cortex and hippocampus in monkeys

Monkeys with immunotoxic lesions of both the basal nucleus of Meynert and the vertical limb of the diagonal band of Broca (NBM+VDB) lost cholinergic innervation throughout the cortex and hippocampus. They were impaired at learning discriminations between objects differing in either few, or many, attributes and at learning visuospatial conditional discriminations. Monkeys with immunotoxic lesions of the NBM lost cholinergic innervation of the neocortex only. Initially, they were unable to learn a simple visual discrimination where the stimuli differed in a limited number of attributes but they were unimpaired at learning discriminations between objects that differed in more attributes. They were mildly impaired at learning a visuospatial conditional task. The impairment exhibited by monkeys with lesions of the NBM alone ameliorated with time but that following NBM+VDB lesions did not. Previous experiments have shown that monkeys with immunotoxic lesions of the VDB alone are impaired at learning visuospatial conditional discriminations but are unimpaired at learning simple visual discriminations. When monkeys with NBM lesions were given excitotoxic lesions of the CA1 field of the hippocampus the learning impairment on discriminations between objects which differed in few attributes was reinstated. Pretreatment with a cholinergic agonist improved learning ability on visual discrimination learning in all monkeys but this improvement was significantly greater in monkeys with lesions of the NBM. On conditional discrimination learning, which is particularly sensitive to hippocampal damage, pilocarpine produced a significant improvement in monkeys with NBM+VDB lesions (where the hippocampal dysfunction was cholinergic) but not in monkeys with NBM+CA1 lesions (where the hippocampal damage was structural).     

低场FLAIR技术在急性脊髓炎中的诊断价值

目的 探讨快速液体衰减反转恢复(FLAIR)技术在急性脊髓炎中的应用价值. 方法 用0.5T超导磁共振(MR)机对52例健康者和33例急性脊髓炎患者行MR检查,扫描序列为TlM.T2WI,FLAIR序列,33例患者中23例作了T1WI增强扫描,比较FLAIR和TSE-T2WI两种序列对病灶的显示能力. 结果 33例患者33处病灶,FLAIR发现病灶33处,检出率100%,TSE-T2WI发现病灶23处.检出率69.7%:在显示病灶边缘情况方面,FLAIR显示清楚者32例,T2WI显示清楚者13例.在发现病灶及显示病灶边缘方面两者差异有统计学意义(P<0.01). 结论 FLAIR技术在脊髓炎的诊断中有较高的临床应用价值.应作为本病检查的常规方法.     

Cerebellar lesions in the PICA but not SCA territory impair cognition

The authors sought to clarify whether lesions in different parts of the cerebellum result in differential cognitive and affective impairment. Six subjects with cerebellar lesions due to posterior inferior cerebellar artery (PICA) infarction, five subjects with lesions in the SCA vascular territory, and 11 matched controls were administered a battery of standard neuropsychological tests. PICA lesions but not SCA lesions resulted in cognitive and affective deficits pointing to a dominant role of posterior cerebellar regions in cognitive and affective processing.     

Magnetic resonance imaging in multiple sclerosis. Sensitivity and correlation with the clinical picture

The aim of imaging the brain in Multiple Sclerosis (MS) is to prove the dissemination of lesions, so critical for the diagnosis and so difficult to ascertain clinically. Our study included 21 patients with clinically definite (12) and probable (9) MS. A 21 patients underwent a neurological standard examination, a double-dose delayed CT scan and a Magnetic Resonance Imaging with a superconducting 0.5 Tesla magnet. Jointed slices were performed with a T2-weighted Spin-Echo sequence (TE 60, 120; TR 2000 msec). MRI detected 640 lesions in 20 patients while CT scan detected only 24 lesions in 9 patients. Technical limiting factors are discussed. Abnormalities in MRI were high-intense spots, blotches and streaks, located predominantly in the periventricular area. Capping lesions were common around the ventricular horns. "Plaques" were visualized in the posterior fossa. For each patient, the total surface of the lesions was calculated and was found to be related with the presence of lesions and with the cortical atrophy on CT scan. A correlation between the surface of lesions calculated by MRI and the disability scale was found especially in the group of patients with clinically proven cerebral lesions, while patients with predominantly spinal forms had a significantly lower surface of lesions. This finding could yield a new quantitative evaluation of the MS pathologic process which could be used to assess therapeutic efficacy.     

Cerebral white matter lesions and depressive symptoms in elderly adults

BACKGROUND: There is evidence for a vascular cause of late-life depression. Cerebral white matter lesions are thought to represent vascular abnormalities. White matter lesions have been related to affective disorders and a history of late-onset depression in psychiatric patients. Their relation with mood disturbances in the general population is not known. We investigated the relation between white matter lesions and the presence of depressive symptoms or a history of depression in a population-based study. METHODS: In a sample of 1077 nondemented elderly adults, we assessed the presence and severity of subcortical and periventricular white matter lesions using magnetic resonance imaging, presence of depressive symptoms, and history of depression. Using multiple regression analysis, we examined the relation among white matter lesions, depressive symptoms, and history of depression. RESULTS: Most of the subjects had white matter lesions. Persons with severe white matter lesions (upper quintile) were 3 to 5 times more likely to have depressive symptoms as compared with persons with only mild or no white matter lesions (lowest quintile) (periventricular odds ratio [OR] = 3.3; 95% confidence interval [CI], 1.2-9.5; subcortical OR = 5.4; 95% CI, 1.8-16.5). In addition, persons with severe subcortical but not periventricular white matter lesions were more likely to have had a history of depression with an onset after age 60 years (OR = 3.4; 95% CI, 1.1-10.7) compared with persons with only mild or no white matter lesions. CONCLUSION: The severity of subcortical white matter lesions is related to the presence of depressive symptoms and to a history of late-onset depression.     

Neuropathological study of severely handicapped children: relationships of cortical and subcortical destructive lesions

Neuropathological examinations were performed on 30 autopsy cases of severely handicapped children. Among them, 11 cases showed bilateral cerebral destructive lesions. The cerebral lesions were divided into three groups; six cases with dominantly grey matter lesions, three with dominantly white matter lesions and two with combined grey and white matter lesions. The cortical lesions were found in the fronto-parieto-occipital lobes and cingulate gyri, while undersurface of the temporal lobes showed less destruction. The white matter lesions, consisting of marked gliosis and atrophy accompanied by ventricular dilatation, were remarkable in the area extending from the periventricular region to the centrum semiovale. These changes were more apparent in the occipital lobes. Cerebellar lesions were found in nine cases, which also were classified into grey matter and white matter lesions. The extent and characteristics of these lesions resembled those of the cerebral lesions. The basal ganglia showed no remarkable destruction in the cases with severe cortical and subcortical damages. It was assumed that these nuclei had survived the disconnection from the cortex. Thalamic lesions were observed in six cases, mainly restricted to the dorsal and/or lateral nuclei. No relationship was found between these thalamic lesions and the extent or intensity of cerebral destruction. It is suggested that each of the thalamic nuclei has a different characteristic vulnerability to such destructive conditions.     

Effects of dorsal, mediobasal and laterobasal septal lesions in the rat: reflexive fighting and pain thresholds.

The experiments were carried out on adult male rats of the Wistar strain, quality SPF. These were divided into experimental groups so that each group contained siblings. The functional differentiation of the rat septum was examined using the method of reflexive fighting on successive exposure to stimulating impulses. Rats with septal lesions differed from intact ones in a higher level of reflexive fighting during the first to ninth sessions. During the tenth to eighteenth sessions this difference was preserved but, in addition, differences became manifested between rats with septal lesions according to the localization of their lesions. The rats with laterobasal lesions had a lower level of reflexive fighting than those with dorsal and mediobasal lesions. The application of the technique of reaction to electric current showed likewise a functional differentiation of the septum; however, of all experimental criteria, the differences were found only in vocalization where control rats exhibited a higher threshold than those with septal lesions. Among the latter, those with dorsal lesions had a lower threshold than either the rats with mediobasal or laterobasal lesions. The participation of conditioned and unconditioned components in the mechanism of these phenomena is discussed.     

Motor impersistence: a right-hemisphere syndrome

We studied motor impersistence with a standardized clinical test of sustained actions, both in patients with acute focal stroke lesions, who were matched for age and size of lesion, and normal controls. Patients with right-sided lesions had significantly more impersistence than did those with left-sided lesions. The most discriminating tests were eye-closure, mouth-opening, tongue-protrusion, and gaze to the left. Right central and frontal lesions seemed to be more responsible for motor impersistence than were posterior or left-sided lesions. Although motor impersistence is sometimes seen with diffuse cerebral disease, it is also a sign of right-hemisphere lesions; the phenomenon is probably related to mechanisms of directed attention that are necessary to sustain motor activity.     

Ipsilesional line bisection bias in patients with chronic parietal lesions

The current study investigated whether an ipsilesional bias in line bisection, a conventional measure for diagnosing hemispatial neglect, persists even in the absence of this syndrome in patients with chronic lesions restricted to posterior association cortex or dorsolateral prefrontal cortex. Both left and right hemisphere parietal lesions produced ipsilesional bisection errors, and to a comparable degree. Patients with lesions in frontal cortex, on the other hand, did not show a consistent bias. We conclude that chronic parietal lesions produce an ipsilesional bias in line bisection, even in the absence of other clinical signs of neglect, and that left hemisphere lesions can affect line bisection to the same degree as right hemisphere lesions.