Impairment in clock-time estimation following right hemisphere ischemic damage.

In order to assess clock-time estimation (CTE), we asked "what time is it in your opinion?" to 48 recent stroke in-patients, 21 with right (RH), 27 with left hemispheric (LH) lesions, and to 20 control in-patients without brain lesions (C). Errors were measured in terms of the number of minutes by which the estimated clock-time was later (advance errors) or earlier (delay errors) than the real clock-time. CTE was considered pathological when exceeding the mean advance or delay errors observed in control patients plus 2.5 standard deviations. The estimation of the duration of a short psychological interview was also assessed. CTE, and not duration estimation, was disturbed in patients. RH patients made significantly more pathological advance errors than LH patients (43% vs. 12%). This study points out the RH dominance for CTE in stroke patients.

Prediction of malignant middle cerebral artery infarction by diffusion-weighted imaging.

BACKGROUND AND PURPOSE: This study was designed to analyze whether early diffusion-weighted imaging (DWI) provides reliable quantitative information for the prediction of stroke patients at risk of malignant brain infarct. METHODS: We selected 28 patients with a middle cerebral artery (MCA) infarct and proven MCA or carotid T occlusion on DWI and MRI angiography performed within 14 hours after onset (mean 6.5+/-3.5 hours, median 5.2 hours). Of these, 10 patients developed malignant MCA infarct, whereas 18 did not. For the 2 groups, we compared the National Institutes of Health Stroke Scale (NIHSS) score at admission, site of arterial occlusion, standardized visual analysis of DWI abnormalities, quantitative volume measurement of DWI abnormalities (volume(DWI)), and apparent diffusion coefficient values. Univariate and multivariate discriminant analysis was used to determine the most accurate predictors of malignant MCA infarct. RESULTS: Univariate analysis showed that an admission NIHSS score >20, total versus partial MCA infarct, and volume(DWI) >145 cm(3) were highly significant predictors of malignant infarct. The best predictor was volume(DWI) >145 cm(3), which achieved 100% sensitivity and 94% specificity. Prediction was further improved by bivariate models combining volume(DWI) and apparent diffusion coefficient measurements, which reached 100% sensitivity and specificity in this series of patients. CONCLUSIONS: Quantitative measurement of infarct volume on DWI is an accurate method for the prediction of malignant MCA infarct in patients with persistent arterial occlusion imaged within 14 hours of onset. This may be of importance for early management of severe stroke patients.

[Unilateral benign episodic mydriasis]. / Mydriase épisodique unilatérale bénigne.

Ophthalmoplegic migraine is a rare phenomenon. In this setting, extrinsic as well as intrinsic fibers of the third nerve are involved. We report 2 cases of isolated, unilateral, remitting, mydriasis and describe 23 other cases already published. CT scan, MRI and angiogram were always normal when performed. The pathophysiology of this syndrome is probably related to a migrainous manifestation.

[Intramedullary epidermoid cyst. Contribution of magnetic resonance imaging]. / Kyste épidermoïde intra médullaire. Apport de l'imagerie par résonance magnétique.

Epidermoid tumors are seldom found as a cause of spinal cord compression; still fewer involve the spinal cord itself. We report a case of a thoracic intramedullary epidermoid tumor documented by MRI.

[Endoluminal dilatations and stenosis of symptomatic vertebral arteries]. / Dilatations endo-luminales des sténoses des artères vertébrales symptomatiques.

Surgical treatment of symptomatic atherosclerotic stenosis of vertebral arteries has been proposed for many years but this technique remains quite confidential due to technical difficulties and relatively high risks. Transluminal angioplasty has been proposed and we developed a simplified technique using coronary stent placement. The aim of this study was to evaluate the feasibility and efficacy of transluminal angiography with primary stenting for proximal stenosis for vertebral arteries. Eleven patients with symptomatic atherosclerotic stenosis of vertebral arteries were treated by trans luminal angioplasty with primary stent placement. Two patients, one with stenosis of the proximal vertebral artery and one with distal stenosis of the vertebral artery where only treated by transluminal angioplasty. In all cases transluminal angioplasty and stenting were feasible with restitution ad integrum of the diameter of the artery in 98 cases and with residual moderate stenose (<20%) in 5 cases. All patients were followed for more than one year, only one patient had recurrence of symptoms, but he stopped spontaneously the anti platteless drugs. Vertebro basilar symptoms disappeared completely in 12/13 cases and were improved in 1/13 cases. No restenose of the artery was observed on control (echodoppler) excepted in one case, where a tight stenose of pre vertebral sub clavian artery developed. Transluminal angioplasty for symptomatic stenosis of vertebral artery appears as a very successful technique with a low complication rate. It should be proposed in many cases of vertebrobasilar insufficiency related with tight vertebral artery stenosis.

DWI prediction of symptomatic hemorrhagic transformation in acute MCA infarct.

PURPOSE: Symptomatic hemorrhagic transformation is a severe complication of acute ischemic stroke which occurs at a higher frequency after thrombolysis. The present study was designed to analyze whether early DWI can be used for predicting the risk of hemorrhagic transformation with clinical worsening in MCA stroke patients. MATERIALS AND METHODS: Of 28 patients with a middle cerebral artery (MCA) infarct and proven MCA or carotid T occlusion on DWI and MR angiography performed within 14 hours after onset (mean 6.5 +/- 3.5 hours, median 5.2 hours), 4 developed hemorrhagic transformation with clinical worsening, while 24 did not. For the 2 groups, we compared admission NIHSS score, site of arterial occlusion, volume of DWI abnormalities, and several apparent diffusion coefficient (ADC) measurements: ADC(infarct) (mean ADC value of the whole infarct), ADC(core) (peak ADC decrease as calculated in a 57 mm(2) circular ROI, manually centered on the ischemic area with the lowest ADC value on the ADC maps), ADC(superficial) and ADC(deep). Discriminant function analysis was used to determine the most accurate predictors of symptomatic hemorrhagic transformation. RESULTS: The best predictor was the ADC(core) (F=5.34, p=2.9%, cut-off value=300 x 10(-6) mm(2)/s). This monovariate model allowed to correctly classify all 4 patients (ADC(core) 300 x 10(-6) mm(2)/s) with subsequent symptomatic hemorrhage, and 17 of the 24 patients without symptomatic hemmorrhage (ADC(core)>300 x 10(-6) mm(2)/s) (100% sensitivity, 71% specificity). CONCLUSION: Although preliminary, these results suggest that a simple measurement of minimum ADC values within an acute MCA stroke could be useful in targeting those patients with a high risk of severe hemorrhagic transformation.

[Asomatognosia and oral drive: a psychoanalytical perspective]. / Asomatognosie et troubles de l'oralité. Une lecture psychanalytique.

OBJECTIVE: The psychoanalytic concept of specular image refers to the complex construction that associates the body image with the language coordinates of the individual, thus making him/her a human subject. The acquisition of this specular image implies the loss of corporeal exchanges between mother and child, i.e., the "neutralization" of those body parts or extensions where these exchanges take place. These conceptions of body image and subjectivity lead to the hypothesis that neurological disturbances of body schema may alter the patients' subjectivity and their relation to the lost "object" insofar as they alter body image. MATERIAL: In the present paper, we present two patients aged under 50, with a unique first ever stroke due to ischemia in the right middle cerebral artery territory and asomatognosia. METHODS: On one hand, Bisiach's protocol was used to assess hemiplegia, sensory troubles, visual troubles, hemineglect and anosognosia, and adapted to assess asomatognosia. On the other hand, subjective data were gathered during a semistructured interview and a self-portrait test. RESULTS: This showed that asomatognosia was accompanied by a destructuration of body image and aberrant oral manifestations involving the paralyzed hand. DISCUSSION-CONCLUSION: The psychological positive phenomena accompanying asomatognosia might correspond to the intrusion of the lost object in the patients' psychic reality, due to the alteration of body schema and body image.

Grafting odorant binding proteins on diamond bio-MEMS.

Odorant binding proteins (OBPs) are small soluble proteins found in olfactory systems that are capable of binding several types of odorant molecules. Cantilevers based on polycrystalline diamond surfaces are very promising as chemical transducers. Here two methods were investigated for chemically grafting porcine OBPs on polycrystalline diamond surfaces for biosensor development. The first approach resulted in random orientation of the immobilized proteins over the surface. The second approach based on complexing a histidine-tag located on the protein with nickel allowed control of the proteins' orientation. Evidence confirming protein grafting was obtained using electrochemical impedance spectroscopy, fluorescence imaging and X-ray photoelectron spectroscopy. The chemical sensing performances of these OBP modified transducers were assessed. The second grafting method led to typically 20% more sensitive sensors, as a result of better access of ligands to the proteins active sites and also perhaps a better yield of protein immobilization. This new grafting method appears to be highly promising for further investigation of the ligand binding properties of OBPs in general and for the development of arrays of non-specific biosensors for artificial olfaction applications.

Evolving isolated hand palsy: a parietal lobe syndrome associated with carotid artery disease.

Six patients with cerebral ischaemia who presented evolving isolated hand palsy were studied, five prospectively and one retrospectively. The motor deficit involved only the hand and the wrist in some cases. In almost all cases the motor deficit was pseudo-ulnar. None of them had a Babinski sign, all had mild sensory symptoms or signs in the affected hand. CT and MRI disclosed recent infarctions contralateral to the affected hand, in the white matter of the angular gyrus, in a vascular borderzone. Five had a tight stenosis of the internal carotid artery. The pyramidal tract was anatomically spared in three cases, even considering its parietal origin. Consistent with previous data, our study suggests that the parietal lobe is involved in the control of the motor function of the hand. We propose the existence of a new entity, characterized by an evolving non-pyramidal motor deficit in the hand following infarction of the angular gyrus of the inferior parietal lobe.

Diagnosis of acute ischaemic stroke with fluid-attenuated inversion recovery and diffusion-weighted sequences.

We evaluated the feasibility and use of diffusion-weighted and fluid-attenuated inversion-recovery pulse sequences performed as an emergency for patients with acute ischaemic stroke. A 5-min MRI session was designed as an emergency diagnostic procedure for patients admitted with suspected acute ischaemic stroke. We reviewed routine clinical implementation of the procedure, and its sensitivity and specificity for acute ischaemic stroke over the first 8 months. We imaged 91 patients (80 min to 48 h following the onset of stroke). Clinical deficit had resolved in less than 3 h in 15 patients, and the remaining 76 were classified as stroke (59) or stroke-like (17) after hospital discharge. Sensitivity of MRI for acute ischaemic stroke was 98%, specificity 100%. MRI provided an immediate and accurate picture of the number, site, size and age of ischaemic lesions in stroke and simplified diagnosis in stroke-like episodes. The feasibility and high diagnostic accuracy of emergency MRI in acute stroke strongly support its routine use in a stroke centre.

Diffusion-weighted magnetic resonance imaging in a case of cerebral venous thrombosis.

BACKGROUND: Diffusion-weighted imaging (DWI) is the most sensitive MR sequence in acute arterial ischemic stroke but has not yet been evaluated in venous cerebral ischemia. We describe a patient with DWI performed at the acute phase of a venous ischemic stroke. CASE DESCRIPTION: A rapid cerebral MRI including DWI and fast fluid-attenuated inversion recovery (FLAIR) sequences was performed at the acute phase of a venous stroke confirmed by conventional angiography. DWI showed a slight decrease in apparent diffusion coefficient values 3 hours after onset (0.53+/-0.07x10(-3) mm2/s) and was normal 48 hours later (0.064+/-0.15x10(-3) mm2/s). Fast FLAIR sequences showed large left frontoparietal hyperintensities. The lack of a clear decrease in apparent diffusion coefficient values associated with marked FLAIR abnormalities may suggest prominent or early associated vasogenic edema. Physiopathological differences between arterial and venous ischemia may explain the different type of DWI FLAIR abnormalities during the acute phase as well as the better recovery of neurological deficit in venous stroke than in arterial ischemic stroke. CONCLUSIONS: In the context of an acute stroke, the contrast between marked FLAIR and subtle DWI abnormalities on MRI may reflect the venous mechanism of cerebral ischemia.