Subcortical neglect as a consequence of a remote parieto-temporal dysfunction. A quantitative EEG study.

In patients with a right-sided deep-seated lesion, a causal relationship between a cortical dysfunction in the right temporo-parietal region and the occurrence of neglect has been suggested. In the present study we tried to correlate clinical and quantitative EEG data from a sample of 33 right stroke patients divided into two subgroups according to the presence or absence of neglect. A 20-channel EEG cartography system was used for EEG mapping.

Mechanisms of functional restoration after brain injury.

The mechanisms accounting for clinical improvement after brain injury are still a matter of debate. Better knowledge of the recovery process is important for it might be influenced by therapy. This article reviews a number of studies devoted to the physiopathology of recovery from aphasia and visuo-spatial neglect after the acute stage, using various methods (cerebral blood flow and metabolism measurements, dichotic listening, transcranial Doppler ultrasonography, functional magnetic resonance imaging) with special reference to the contribution of methods using activation procedures.

[Communication with the aphasic patient].

The consequences of aphasia with reference to the WHO ICIDH classification are evoked. The role of the physician and the behaviour of the relatives are underlined as well as the main parameters to be taken into consideration to communicate with an aphasic patient. As a rule, a dialogue in quiet surroundings will make communication easier with an aphasic patient.

[Lower limb monoplegia and dissociated hypoesthesia after peridural anesthesia].

Neurological sequelae reported after epidural anesthesia include epidural hematoma, spinal cord ischemic injury and lumbosacral nerve root injury. We describe here a case of monoplegia of the right lower limb associated with an ipsilateral loss of perception of pain and temperature following an epidural anesthesia. MRI was compatible with a right centrolateral infarction in the gray matter of the spinal cord below D8.

Complete mutism after midbrain periaqueductal gray lesion.

Several neurophysiological studies have highlighted the role of the midbrain periaqueductal gray matter (PAG) in the initiation of vocalization in various animal species, from frogs to primates. With regard to humans, only two cases of complete mutism following a lesion to the PAG have been reported so far. This article describes a new case of a patient (GM) who, following an ischemic lesion to the periaqueductal gray region of the midbrain, presented with complete and irreversible mutism, though her language comprehension functions and her non-verbal expression capacity were preserved.

Quantitative EEG in subcortical neglect.

Right-sided capsulo-lenticular strokes may cause left visuo-spatial neglect. The neural mechanism most frequently evoked to account for the occurrence of related cognitive disorders is remote cortical dysfunction in the posterior part of the right hemisphere. We studied 33 patients with capsulo-lenticular stroke, with (n = 16) or without (n = 17) associated subcortical neglect.

Pathogenesis of subcortical visuo-spatial neglect. A HMPAO SPECT study.

The pathophysiology of neuropsychological disorders due to right deep-seated hemispheric lesions remains a debated point. We undertook this study to check the hypothesis according to which remote cortical dysfunction could be responsible for the occurrence of neglect. Twenty-eight patients presenting with a right-sided subcortical stroke were studied.

Subcortical aphasia: a specific clinical picture?

100 aphasic patients were examined with a scorable aphasia battery looking at the frequency of various aphasia types and the possible specificity of clinical pictures in deep-seated lesions. One month after onset, "atypical" aphasiological syndromes proved to be rare and to have the same frequency in patients with cortico-subcortical or capsulostriatal deep-seated lesions. In the latter condition, no specific clinical syndrome was brought out, although verbal comprehension disorders were usually less severe than in cortico-subcortical lesions.

Remote cortical dysfunction as a possible cause of subcortical neglect? A regional cerebral blood flow study.

Cortical remote effects of right deep-seated lesions were studied with two cerebral blood flow measurement methods (two-dimensional xenon-133 inhalation and 99mTc HMPAO SPECT) in a population of 13 right-handed stroke patients. A neuropsychological battery of tests suitable for assessment of possible visual neglect was performed. Neglect was present in 7 cases.

Functional dissociations following bilateral lesions of auditory cortex.

We present two patients with bilateral lesions of the superior temporal cortex who manifested a number of functional dissociations in the auditory domain. The perception of speech and environmental sounds were preserved; yet, the perception of tunes, prosody and voice was impaired. As the processing of melodic but not rhythmic variations in musical sequences was selectively disturbed, the deficit cannot be attributed to a general impairment in auditory memory or sequential processing.

Contribution of remote cortical dysfunction to the pathogenesis of subcortical aphasia: A (99m)Tc-HMPAO SPECT study.

Remote cortical effects of deep-seated lesions were studied by (99m)Tc-hexamethyl-propylenenamine oxime single-photon emission computed tomography at about 50 days after stroke in a population of 16 right-handed aphasic patients. A left-sided regional cortical hypoperfusion was present in all cases. Significant relations were observed between the severity of verbal expression disorders and the degree of regional cortical flow decrease, suggesting that, from a given level of remote dysfunction, the affected cortical areas no longer would be able to play their functional role in language elaboration.

Pure topographical disorientation due to a deep-seated lesion with cortical remote effects.

Lesions producing pure topographical disorientation syndromes are classically located either in the right parietal region either in the right parahippocampal gyrus. The patient described in the present study was admitted to hospital after sudden onset of a left hemiparesis. The lesion at CT scan was located in the posterior limb of the right internal capsule.

Seasonal variation of cerebral hemorrhage in 236 consecutive cases in Brussels.

Background And Purpose: Seasonal variation in the incidence of cerebral hemorrhage has been previously demonstrated. In this study, we sought to identify the climatological data best correlated with this seasonal variation.

Methods: In a retrospectively studied sequential series of 236 patients with nontraumatic cerebral hemorrhage observed in Brussels over a period of 8 years, we cumulatively grouped the dates of stroke occurrence into a single calendar year.

Remote cortical dysfunction in aphasic stroke patients.

We studied the effect of deep-seated left hemispheric lesions on cortical blood flow in 18 right-handed aphasic stroke patients. Regional cerebral blood flow was measured at rest and during the performance of a functional naming test using the two-dimensional xenon-133 inhalation method. Compared with 10 controls, at rest the patients showed regional cortical hypoperfusion in the left frontoparietal region.

Brain activation during a linguistic task in conduction aphasia.

In order to investigate functional cortical reorganization during recovery from conduction aphasia, regional cerebral blood flows (rCBF) were measured by the two-dimensional 133 Xenon inhalation method in ten stroke patients. rCBF measurements were performed at rest and during the performance of a linguistic task, one month and three months after onset. The analysis of flow changes from rest to test condition indicates an increasing contribution of the right hemisphere as time goes on.

Remote effect of deep-seated vascular brain lesions on cerebral blood flow.

We measured regional cerebral blood flow using the xenon-133 inhalation method, at approximately 1 month after onset, in 60 stroke patients who had no evidence of major carotid artery stenosis or occlusion. Their single lesions (43 infarcts and 17 hematomas) were located in the capsulothalamolenticular region, sparing the cortex. Hemispheric mean cerebral blood flow was reduced on the side of the lesion in 25 patients and on both sides in 20.

Pathogenesis of aphasia in deep-seated lesions: likely role of cortical diaschisis.

In order to study the pathophysiology of language disorders due to deep-seated left-hemisphere lesions not involving the cortex, a population of 43 right-handed stroke patients (29 aphasic) presenting with such lesions was studied clinically and by regional cerebral blood flow measurements (two-dimensional xenon-133 inhalation method). Most of the patients were studied sequentially between the 1st and 3rd months after stroke. Cortical diaschisis did not account for the whole clinical picture: the remote effect on the cortex could explain the occurrence of aphasia and its severity but not the type of aphasia.

Evidence of cortical reorganization in hemiparetic patients.

We studied the mechanisms underlying the recovery of motor function of the hand using a bidimensional xenon-133 inhalation technique to measure regional cerebral blood flow at rest and during the performance of a motor task (test condition). The regional cerebral blood flow patterns under rest and test conditions were compared in normal control and in stroke patients with either a cortico-subcortical or a deep-seated lesion. Functional recovery appears to depend upon cortical reorganization involving both hemispheres, particularly in both parietal regions in the subgroup of patients with cortico-subcortical lesions.

Assessment of hemispheric dominance for language in crossed aphasia by two atraumatic methods.

In a right handed patient with crossed aphasia, two atraumatic techniques (regional cerebral blood flow measurements during the performance of a linguistic task and dichotic listening test) were used to assess language lateralization. The prominence of rCBF activation patterns in the right hemisphere and the presence of a clear-cut right ear extinction on the dichotic listening test provide evidence that, is this case, the right hemisphere was dominant for language.

Prognostic value of computed tomography in aphasic stroke patients.

In order to evaluate the prognostic value of CT scan in aphasic stroke patients, a prospective study was performed during the first 3 months of the disease. The severity of the language disorders was assessed by means of a quantitative method. In cortico-subcortical lesions, the verbal expression recovery rate and the final verbal expression and comprehension status depended on the infarct size.

[Agraphia, cortical anarthria and planning disorders as a result of a lesion of the right hemisphere in a right-handed patient].

A right-hemisphere premotor cerebral infarct in a right-handed man from a largely left-handed family caused cortical anarthria and constructional agraphia. The effect of programming difficulties on impaired oral and written expression was demonstrated by the clinical picture of pure agraphia, which could thus be attributed to a primary disorder of programming. Measurements of cerebral blood flow three months after the accident showed that language representation was ambilateral.

Resting CBF sequential study during recovery from aphasia due to ischemic stroke.

Cerebral blood flow (133Xenon inhalation method) has been studied in 30 aphasic stroke patients at 15, 30, 60 and 90 days after onset. In total aphasia the CBF values are low and the regional hypoperfused areas are extensive. In Broca's, Wernicke's and nominal aphasias, resting CBF measurements do not provide the clinician with useful additional information and clinical improvement can by no means be attributed to a resting CBF rise during the observation period.

[Etiology of urinary sphincter disorders following cerebral vascular accidents].

Urological and neurological investigations were carried out in a homogeneous population of 77 hemiplegic patients treated in a neurological rehabilitation department, in an attempt to identify the etiology of secondary bladder dysfunction in such cases, with the aid of computerized data. The following conclusions were reached. Bladder retention was proved to result invariably from a mechanical obstacle.

Lack of evolution of the cerebral blood flow during clinical recovery of a stroke.

Cerebral blood flow and clinical parameters were studied in 30 stroke patients at 15th, 30th, 60th, 90th days after the cerebral insult (Xenon 133 inhalation method). The clinical improvement was not accompanied by a progressive normalization of the CBF at rest. No relationship was found between the clinical data and the CBF values; either on the affected hemisphere or on the contralateral one.