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Query: UMLS:C0038454 (stroke)
 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

EEGs and short-latency somatosensory evoked potentials (SEPs) to median nerve stimulation were recorded during 151 carotid endarterectomies, performed under general anaesthesia. Carotid occlusion did not affect either EEG or SEP in 120 cases (group A). In 31 cases the EEG showed "ischaemic" abnormalities (group B). A temporary shunt was inserted only in 16 B patients showing also severely depressed cortical SEPs within 2 min after carotid occlusion (group B shunt). In 15 B patients in whom SEPs were less affected, the operation was completed without shunt (group B no shunt). One intraoperative stroke occurred in group A and two in group B shunt. No neurological complications occurred in group B no shunt. Overall stroke rate was 2%. On retrospective analysis, latency and amplitude of N20 and P25 waves proved to be uninfluenced by carotid occlusion in group A, but were significantly affected in group B shunt. P25 amplitude alone was reduced in B no shunt. An arbitrary index (need-for-shunt index, NSI) was made in order to rate changes of P25 latency and amplitude. Its mean values were significantly different in the 3 groups. A threshold value is suggested above which shunt is required, as a useful adjunct to EEG, in order to balance prevention of brain ischaemia against the risks of shunt.
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PMID:Role of SEP in identifying patients requiring temporary shunt during carotid endarterectomy. 138 51

The results from a topographic analysis of the early median nerve SEPs allowed to design a method for recording and analysing the SEPs in the routine laboratory. The detailed analysis of the topography of 50 normal subjects revealed: 1. An inter- and intraindividual variability of the location of the maximal amplitudes, 2. A significantly longer latency of the cortical potentials after left side stimulation, 3. A significantly higher amplitude of N20 after left side stimulation and 4. A significantly higher amplitude of the later potentials P25 and N30 after right side stimulation. It was shown that a 4-channel recording from the neck at C7 with a Fz-reference as well as from stimulus contralateral F3, CP3 and P3 or F4, CP4 and P4 with an stimulus contralateral earlobe reference provides all necessary parameters in comparison to an 20-channel recording. The definition of normal values has to take into account these results. Absolute maximum values were taken instead of the standard deviation because all amplitude values were proven to be not distributed normally. In 7 out of 30 MCA-stroke patients pathological SEP amplitudes were obtained using the 4-channel montage, whereas the 1-channel recording from CP3 and CP4 with a Fz-reference revealed normal amplitudes.
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PMID:[Topography of early cortical median nerve somatosensory evoked potentials: results for routine use of the method]. 148 25

We evaluated the effect of nicardipine, a calcium channel blocker, on somatosensory evoked potentials (SEP) in 26 patients with acute cerebral infarction. Post treatment, 58% (15/26) of the N20 and P25 latencies were prolonged in the affected hemispheres; 8% (2/26) were shortened; and 35% (9/26) did not change. The mean N20 and P25 latencies were significantly prolonged two hours post treatment in the affected hemisphere (N20, P less than 0.01, P25 P less than 0.01). Nicardipine (Ni) had no effect on SEP components in the intact hemispheres. Seventy five per cent of the 12 patients with hypertension had a decrease in blood pressure (BP) after taking nicardipine, but there were no undesirable side effects or worsening of neurological signs. Our study demonstrates that nicardipine prolongs the latencies of short-latency components of SEP in the affected hemisphere after acute ischaemic stroke and also decreases BP. These observations suggest that nicardipine therapy might impair neuronal function in the ischaemic zone.
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PMID:Effect of nicardipine on somatosensory evoked potentials in patients with acute cerebral infarction. 226 63

We have used and studied intraoperative cerebral monitoring in order to prevent intraoperative and early postoperative cerebral ischaemia. The techniques examined have included stump pressure measurement, the evaluation of somatosensory evoked potentials (SEPs) and completion intraoperative angiography. Stump pressure was measured in 920 patients and a safety level of 50 mmHg confirmed. Below this value, non-shunted patients were three times more likely to have cerebrovascular accident (CVA). SEPs were prospectively monitored in 72 patients and a mean decrease of N20-P25 in complex amplitude was seen in patients with a positive CT scan. In particular, pathological SEPs were found in 53% of patients with a positive CT scan, and in 54% of those with a contralateral carotid occlusion. In these patients, the N20-P25 amplitude fell progressively in the first 4 min. Using SEPs, the indication for shunting was 42% lower than with the measurement of back pressure and no patient with normal SEPs had a postoperative neurological deficit. The data obtained under local anaesthesia in 25 patients monitored by stump pressure and SEPs did not give better results. Intraoperative completion angiography performed routinely since 1978 has made it possible to reduce the need for immediate reoperation from 10-2%.
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PMID:Intraoperative cerebral monitoring in carotid surgery. 845 40

In order to compare the sensitivity of multichannel derived median nerve SEP with EEG in vascular cerebral lesions we examined 22 normals and 23 patients. SEP components within the first 50 ms could be divided into main waveform patterns: (1) a W-shaped parietal pattern consisting of N20, P25, N35 and P45 in most cases. (2) a frontal pattern with P20 and N30 as well as possibly detectible N24, P28, P33, N40 and P50. (3) a central P22. Two younger normals showed a V-shaped parietal pattern with N20 and P35, a frontal pattern with P20 and N36, and central P22 with a remarkably long latency. All components could be analysed sufficiently by means of three representative electrode positions (stimulation right/left): P3/P4, C3/C4, and F3/F4, which reduces the expense of recording and analysing considerably. 21 patients (91.3%) showed abnormal results in SEP, whereas 14 patients (60.9%) in EEG. A three channel electrode array can increase the usefulness of SEP and detect cerebral dysfunctions in cerebral lesions in spite of normal EEG under routine examination conditions. Analysis of multichannel derived SEPs during treatment and recovery after stroke and search for the prognostic value in the acute stage of the disease should be done in future.
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PMID:Multichannel derived median nerve SEP compared to EEG in patients with vascular cerebral lesions. 1144 39

The study aimed at investigation of clinical and neurophysiological features of pyramidal syndrome in patients with vascular damage of right- and left hemisphere in stroke. Forty patients with consequences of acute brain circulation damage were studied: 21 of them with right hemi-paresis (RHP) and 19--with left hemi-paresis (LHP). Cliniconeurological analysis, transcranial magnetic stimulation (TMS), evoked abdominal reflexes, movement motor potential method and somatosensory evoked potentials were used for the examination. Pronounced paresis, tone disturbance, Babinsky symptom, other extensor pathological feet signs, Zhukovsky hand reflex, pseudobulbar syndrome, gait disorder were determined more frequently in patients with LHP. Patients with RHP were characterized by more expressed distal hand paresis and pathological bending feet signs. Compared to RHP patients, those with LHP displayed significantly longer central conduction in TMS, increase of latent periods of components N20, P25, N30 of somatosensory evoked potentials and motor potential area reduction. Functional features of brain hemispheres may to play a certain role in pyramid syndrome formation, right hemisphere damage being characterized by more expressed pyramid disturbances. The data obtained allow to differentiate a great brain hemispheres role in descending motor control as to inhibiting and activating pyramid influences and hemisphere interactions.
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PMID:[Clinical and neurophysiological analysis of pyramidal syndrome in right and left hemisphere stroke]. 1244 60

The predictive values of early somatosensory evoked potentials (SSEPs) for the functional outcome after stroke are investigated. Ninety-four stroke patients (mean age: 61.2, S.D.: 11.8) with CT confirmed diagnoses of middle cerebral artery (MCA) infarction in 71 and supratentorial intracerebral hemorrhage in 23. Median and tibial SSEPs were recorded within 3 days of onset. SSEP parameters were compared to motor (MRC) and functional ability (Barthel index) followed up at 1, 3, 6 and 12 months. Upper limb MRC remains the strongest single predictor of functional outcome, determining 54.3% of Barthel index value at 12 months. The highest predictive value among SSEP parameters has N20-P25 amplitude ratio-34.5%. Combined application of upper limb MRC and N20-P25 amplitude ratio provided significantly stronger prognostic information-66%. Combined assessment of SSEP parameters and muscle power in acute stroke considerably improves prediction of functional outcome.
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PMID:Prognostic value of median and tibial somatosensory evoked potentials in acute stroke. 1585 59

The direct injection of endothelin-1 (ET-1) into brain parenchyma was recently suggested as a suitable model of stroke. The present study was designed to assess whether intrahippocampal injection of ET-1 in immature rats causes neurodegeneration and immediate seizures, and results in impairment of motor development, cognitive decline, epilepsy and chronic hippocampal lesion. ET-1 was injected unilaterally into the dorsal hippocampus in doses of 20 or 40 pmol at the age of 12 (P12) or 25 (P25) days. Video-electroencephalographic monitoring performed during 100 min after the injection of ET-1 demonstrated the development of convulsive epileptic seizures in 75-100% of animals of individual age-and-dose groups. Long-term behavioral follow-up did not reveal impairment of motor development in any dose-and-age group. At 2 months after ET-1 injection, impairment of spatial memory occurred only in rats with 40 pmol of ET-1 at P12. At 3 months after ET-1 injection spontaneous electrographic seizures occurred in 62.5-100% animals of both ages with no relation to the dose used. Seizures were always non-convulsive. The total seizure duration per 24 h was higher in the P12 than the P25 group, suggesting more severe epilepsy. The extent of the hippocampal lesion increased with the dose of ET-1 and was significantly higher in the P12 than the P25 group. The severity of the ET-1-induced lesion correlated positively with total seizure duration per 24 h at both ages. Our results document that early intrahippocampal injection of ET-1 results in lesion development and both immediate seizures and chronic epilepsy in either age group. Cognitive impairment occurred only in rats with ET-1 injection at P12.
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PMID:Intrahippocampal injection of endothelin-1 in immature rats results in neuronal death, development of epilepsy and behavioral abnormalities later in life. 1683 44

To explore the prognostic accuracy for unfavorable outcome with short-latency somatosensory evoked potential (SLSEP) and brainstem auditory evoked potential (BAEP) in patients with severe stroke, 100 acute severe supratentorial stroke patients [Glasgow Coma Scale, (GCS) <or=12] were monitored with SLSEP, BAEP, and GCS within 1 week after onset. All patients were evaluated with modified Rankin scale 6 months after onset-0 to 4 being favorable outcome, whereas 5 to 6 designated unfavorable outcome. Correlations between SLSEP, BAEP, or GCS and prognosis were analyzed respectively. Of all 100 patients, 92 suffered unfavorable outcome, only 8 had favorable outcome. GCS 3 to 8 was significantly correlated with unfavorable outcome (P < 0.01). Absence of cortical SLSEP (N20 response, at least one side), abnormal bilateral N20-P25 amplitude ratio, Cant grading 3, Judson grading 3, and Haupt grading 3 to 4 were all significantly correlated with unfavorable outcome (P < 0.01). Poor differentiation or absence of BAEP wave V, Cant grading 3, Hall grading 3 to 4, and Haupt grading 3 to 4 were all significantly correlated with unfavorable outcome (P < 0.01). Absence of SLSEP N20, poor differentiation or absence of BAEP wave V, and Hall and Haupt grading of BAEP were acceptably consistent with prognosis (kappa >0.4). Prognostic accuracy of SLSEP, BAEP, and GCS for unfavorable outcome was very high (94.3%-98.7%), among which BAEP is the highest (97.5%-98.7%). The overall prognostic accuracy of SLSEP (90.5%-93.7%) was higher than BAEP (83.0%-89.4%) and GCS (82%). The prognostic accuracy of SLSEP and BAEP for unfavorable outcome in patients with severe supratentorial stroke was high, whereas for favorable outcome, it was low. The overall prognostic accuracy was higher than GCS.
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PMID:Parameters and grading of evoked potentials: prediction of unfavorable outcome in patients with severe stroke. 2008 5

More than half of neonatal stroke survivors have long-term sequelae, including seizures and neurological deficits. Although the immature brain has tremendous potential for recovery, mechanisms governing repair are essentially unexplored. We investigated whether magnetic resonance imaging (MRI) early or late after transient middle cerebral arterial occlusion in postnatal day (P) 10 rats can serve as an intermediate endpoint for long-term studies. Injured animals selected by diffusion-weighted MRI during middle cerebral arterial occlusion were scanned using T2-weighted MRI at P18 and P25 (injury volumes on MRI and histology were compared) or were subjected to contrast-enhanced MRI at P13 to characterize cerebral microcirculatory disturbances and blood-brain barrier leakage. Injury volume during middle cerebral artery occlusion did not predict histological outcome at 2 weeks. Major reductions in injury volume occurred by P18, with no further changes by P25 and correlated with histological injury. Cerebral perfusion was significantly reduced in the injured caudate but blood-brain barrier leakage was small. Therefore, conventional T2-weighted MRI performed during a subchronic injury phase predicts a long-term histological outcome after experimental neonatal focal stroke.
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PMID:Magnetic resonance imaging (MRI) as a translational tool for the study of neonatal stroke. 2167 Mar 90


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